A thermally insulating housing has one housing shell inside another. The two housing shells are at least largely vacuum-tight, they are spaced apart from one another by a thermal insulation layer, and they are connected to one another in a vacuum-tight fashion. A useful space inside the thermally insulating housing is accessible through a loading opening. The housing shells are tubular elements which are closed in a vacuum-tight fashion at one of their openings with a cover which is at least very largely vacuum-tight. The remaining opening serves as the loading opening of the housing.

The invention relates to a thermally insulating housing with two housing shells that are arranged one inside the other, that are at least largely vacuum-tight, that are spaced apart from one another by a thermal insulation layer, and that are connected to one another in a vacuum-tight fashion. The housing bounds in a thermally insulating fashion a useful space which is accessible through a loading opening.
In household appliances whose thermally insulating housing is based on vacuum insulation technology, the prior art joins together the vacuum-tight boundary walls, which serve as top layers, in wall pieces that are usually produced from stainless steel plate. The individual pieces are typically welded to one another. In this known manufacturing technology, the boundary walls are produced using a plate construction method, the individual wall sections being produced as planar sheet-metal blanks and welded to one another.
Furthermore, in the context of housings for domestic refrigerating appliances which are thermally insulating and are based on vacuum insulation technology, it has been known to assemble the boundary walls of the housing, which walls serve as the inner and outer enclosures, from preshaped profile sections that connect a plurality of wall sections to one another in one piece. Here, in each case one section which is formed in a U or L shape is used for one of the boundary walls, the base, the top and one side wall being produced by the U section and the rear wall and a further side wall being produced by the L section. In order to manufacture the inner and outer enclosures, the two sections are either butt welded to one another or welded to one another along joining flanges which are specially provided for this purpose.
The two housing construction techniques have in common that cutting tools which are complex in terms of tool technology and are thus cost-intensive have to be used in order to be able to ensure that the individual elements which are necessary to manufacture the top walls are joined together and connected in a vacuum-tight fashion in the case of mass-produced housing structures. Nevertheless, in both construction techniques, in particular if the individual elements are butt connected to one another, it is not possible to entirely exclude the possibility of leaks occurring which adversely affect the vacuum insulation. In order to be able to avoid this problem with the construction concept comprising a U section and an L section, the procedure has been adopted of providing the sections with so-called joining flanges at their connecting joints. The sections are then welded to one another along the flanges. However, this results in a situation in which the joining flanges project into the insulation volume generated by evacuation, and not only impede the insertion of insulation material which supports the two containers with respect to one another but also adversely affect the thermal insulation capacity of the vacuum insulation by reducing the possible insulation width in their region. Furthermore, for the boundary walls which serve as inner and outer containers, such manufacturing techniques result in the problem that, owing to the abrupt junctions which result when the individual elements are joined together, the welding procedure cannot be carried out continuously over the corner region of the components to be connected.
It is accordingly an object of the invention to provide a thermally insulating housing, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which uses simple structural measures.
With the foregoing and other objects in view there is provided, in accordance with the invention, a thermally insulating housing, comprising:
an outer housing shell and an inner housing shell disposed inside the outer housing shell, the inner and outer housing shells being at least largely vacuum-tight, spaced apart from one another by a thermal insulation layer, and vacuum-tightly connected to one another;
the housing shells bounding, in a thermally insulating fashion, a useful space accessible through a loading opening defined by the housing shells;
each of the housing shells being a tubular element having a first opening vacuum-tightly closed off with a substantially vacuum-tight cover and a second opening and the tubular element of the inner housing shell being formed with a second opening defining the loading opening of the housing.
In other words, the object of the invention are satisfied by the production of the housing shells from a tubular element which is closed in a vacuum-tight fashion at one of its openings with a cover which is of at least very largely vacuum-tight design, while the remaining opening of the inserted tubular element serves as a loading opening of the housing.
By using tubular elements for constructing the housing shells, it is possible not only easily to produce various housing cross sections by using semifinished products, for example, but also to make a housing structure in which only the rear wall has to be positioned with respect to the tubular elements by using clamping and joining devices and welding it thereto. In this way, not only is the expenditure on tools reduced but also particularly the length of the welding seams is made smaller to the benefit of a significantly increased vacuum-tightness owing to the welding seam-less wall junctions of the tubular element. In addition, such a housing manufacturing technique makes cornered areas on the tubular element possible, as a result of which the welding procedure with the cover which serves as a rear wall of the housing shell can progress continuously. In addition, the use of tubular elements which are equipped with radii in their corner regions makes it possible to use a connection section whose section elements which have to be inserted into the corner region are produced in one piece, for example by shaping a planar sheet-metal blank.
In accordance with an added feature of the invention, the tubular elements have a rectangular (e.g. square) base surface, and the cover sealing the first opening is a shell cover.
The shell-like design of the cover which serves as a rear wall avoids an abrupt junction with the tubular element which would entail a certain degree of processing unreliability in terms of production technology, since when the shell walls are joined together with the walls of the tubular element the cover is positioned with sufficient accuracy with respect to the tubular element. As a result, the expenditure in terms of clamping and positioning is significantly reduced.
In accordance with an additional feature of the invention, the shell cover engages over free edges defined around the first opening of the tubular element and is vacuum-tightly secured to the tubular element.
This method of connection between the cover and the tubular element produces a so-called overlap joint which, owing to the wall thicknesses of the shell walls and of the tubular element walls one on top of the other makes it possible to connect the two components in a vacuum-tight fashion with a high processing speed, for example in the event that the tubular element and the covers are produced from stainless steel plate or steel plate with a corrosion-protected surface. The engagement of the shell walls over the free edges of the openings in the tubular element forcibly centers the rear wall with respect to the tubular element.
In accordance with an alternative feature of the invention, the shell cover is insertible into the first opening of the tubular element and is vacuum-tightly secured in the first opening.
As a result, a stepless surface on both tubular elements is easily produced, the stepless shape of the inserted tubular element significantly facilitating the process of filling the element with thermal insulation material, such as open-celled polyurethane foam or polystyrene foams, for example, while the stepless implementation of the external housing shell can serve without any postprocessing as a visible surface for the thermally insulating housing. If the shell edges are turned toward the free edges of the tubular element, the cover and the tubular element can particularly easily be connected to one another in a vacuum-tight fashion, for example by seam welding, if they are produced for example from a stainless steel plate or corrosion-protected steel plate.
In accordance with a further feature of the invention, the shell cover is formed with a stepped recess defining a machine space in the insulating housing. A shell cover is particularly suitable with regard to the machine space recess. The machine space which serves as a recess can be manufactured particularly expediently and particularly dimensionally rigidly in terms of production technology if the shell-like cover is produced by deep drawing a stainless steel plate or a corrosion-protected steel plate.
In accordance with again an added feature of the invention, the shell cover is formed by deep drawing a stainless steel plate or a corrosion-protected steel plate.
In accordance with again an additional feature of the invention, the tubular elements are formed by bending a stainless or corrosion-protected steel plate and by vacuum-tightly welding the free ends of the steel plate to one another.
Such a solution makes it possible to dimension the tubular elements differently from the standardized tubes, in particular in terms of the shaping in their corner regions. As a result, the procedure of welding a connection section, connecting the two tubular elements to one another in a vacuum-tight fashion on the loading side, to the tubular elements can be carried out continuously with high processing reliability and high processing speed.
With the above and other objects in view there is also provided, in accordance with the invention, a refrigeration appliance, which comprises a thermally insulating housing as described in the foregoing.
A thermally insulating housing of a refrigerating appliance can be manufactured in a particularly reliable way in terms of processing and yet cost-effectively with the thermal-insulating housing as claimed.
In addition, a housing of a refrigerating appliance which can be disposed of in a particularly environmentally friendly way with a high thermal insulation capacity is produced.
A thermally insulating cooker muffle of a household oven can be manufactured in an equally particularly reliable way in terms of processing, robustly and with a high processing speed. Such an oven muffle can not only be disposed of in a particularly environmentally friendly way but is also thermally insulating to a high degree.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a thermally insulating housing, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.


An integrated circuit (I/C) assembly includes a dedicated voltage sensor line for determining with a high degree of accuracy the operating voltage at a predetermined sensor point on the IC die. The dedicated voltage sensor line connects the sensor point to an input/output (I/O) structure of the IC die, which in turn is connected to a voltage sense pin on the package of the IC assembly. In this manner, an end user can accurately monitor the operating voltage at the voltage sensor point on the IC. Additionally, an end user can connect a control circuit to the voltage sensor pin to control either the supply voltage or secondary parameters.

This invention relates to an integrated circuit (IC) assembly that permits a user to monitor the voltage applied at the core of the IC.
Programmable logic devices (PLDs) are user configurable integrated circuits (ICs) that implement digital logic functions. Field programmable gate arrays (FPGAs), one type of PLD, typically include configurable logic blocks (CLBs), input/output (I/O) blocks, and a programmable routing matrix for interconnecting the CLBs and I/O blocks. FPGAs, in general, are described in U.S. Pat. Re 34,363, reissued on Aug. 31, 1993 and incorporated by reference herein.
In the Virtex(trademark) family of FPGAs, the programmable routing matrix provides five types of routing resources. xe2x80x9cThe 1999 Xilinx Programmable Logic Data Bookxe2x80x9d, pages 3-10 to 3-12. The first type of routing resource, local routing, is used for interconnecting elements within each CLB and horizontally adjacent CLBs. The second type of routing resource, general purpose routing, is located in the horizontal and vertical routing channels associated with the rows and columns of CLBs. General purpose routing includes general routing matrices (GRMs) that provide CLBs access to the general purpose routing, single-length lines that connect adjacent GRMs, buffered Hex lines that connect GRMs six blocks away, and long lines that distribute signals across the FPGA. The third type of routing resource, I/O routing, provides an interface between the CLB array and the I/O blocks. The fourth type of routing resource, dedicated routing, is provided for on-chip tristate buses and for carry signals. In the Virtex FPGA, four partitionable tristate bus lines are provided for each CLB row and two nets per CLB propagate carry signals vertically to the adjacent CLB. Finally, the fifth type of routing resource, global routing, distributes clocks and other signals having high fanout throughout the device. Primary global routing includes four dedicated global nets for distributing clock signals. Secondary global routing includes 24 backbone lines, 12 lines at the top of the chip and 12 lines at the bottom, that can distribute clock or non-clock signals.
Other families of FPGAs provide different routing resources as well as different CLB and I/O block elements. Other types of PLDs, such as complex programmable logic devices. (CPLDs), also vary siginificantly in architecture.
Due to the variability of function generators, I/O blocks, and routing resources, PLDs have a wide range of power consumption. Moreover, typically because of system constraints, PLDs must also operate under a wide range of frequencies, which also affects their power consumption. Finally, as PLDs are being designed with reduced process geometries, PLDs have lower operating voltages, thereby also affecting their power consumption.
A PLD assembly typically experiences a voltage drop from the resistances corresponding to its various components. Ohm""s Law states that a voltage is equal to the product of the current flowing through a component and that component""s resistance (V=Ixc3x97R). Therefore, as current flow increases in the PLD, the voltage drop experienced in the PLD assembly increases proportionally. As a result, the voltage applied at the core of the IC die in the PLD assembly can be significantly lower than the supply voltage. Moreover, with the trend toward lower supply voltages, there is very little margin for voltage drop before reduced performance and/or functional errors may occur at the core of the IC die.
To address these concerns, those skilled in the art have proposed several solutions. For example, one typical solution is to provide a voltage regulator at a location on the printed circuit board (PCB) that is central to its destination ICs. In this manner, the resistive path to the PLD is reduced and any voltage drop on the path is minimized. Occasionally, centralized voltage regulators also use a sensor point located on the PCB to regulate voltage at that localized point. With such solutions, however, the voltage drop of the PLD itself is not monitored or reduced.
Another proposed solution is to add more power pins to the PLD, thereby reducing the effective length of resistive paths within the PLD. However, with increased functionality requirements, many PLDs are already pad limited. Therefore, the advantage of a possible reduced voltage drop is more than offset by the significant disadvantage of reduced input/output connectivity.
Therefore, a need has arisen for a structure and method that can accurately monitor the voltage at a particular location on the PLD as well as compensate for a voltage drop on the PLD, all without significantly affecting input/output connectivity.
The present invention addresses these problems by adding a sensor point on an integrated circuit (IC) die. In one embodiment, the sensor point is centrally located on the IC die and a dedicated sensor trace connects the sensor point to one of a plurality of input/output (I/O) structures located at the periphery of the IC die. A power bond wire connects that I/O structure to a dedicated voltage sensor pin provided on the IC""s package.
In this manner, the end user can accurately monitor the voltage at the sensor point on the IC die. This information can then be advantageously used to regulate the power supply on the IC die. Specifically, if the voltage is deviating from an acceptable range, the end user can provide a different external voltage, thereby ensuring a proper internal operating voltage on the IC die.
Moreover, information from the sensor point can also be used to improve various engineering features including circuit architecture, packaging, printed circuit board design, and other design areas. Additionally, information from the sensor point can be used to control secondary system parameters, such as clock speed, fan speed, software routines, and IC programming.

Direct current regulation on integrated circuits under high current design conditions


A coffee mug (60) with interchangeable accessories that include a coffee mug body (62) with a groove (70) around the upper outside surface and a lid (76) removably inserted into the body. A replaceable handle bracket (84) is attached to the groove in the body and a detachable handle (100) is connected to the bracket and held in place with a clip (102). A removable docking station (116) is rotatably attached to a base (72) on the bottom of the coffee mug The accessory lid, bracket, handle and docking station are individually selected to personalize the appearance and tactile qualities of the coffee mug.

The present invention relates to coffee mugs in general. More specifically to a mug with interchangeable accessories for personalizing its appearance and tactile qualities.
Previously, many styles and types of coffee mugs have been developed in endeavoring to achieve a pleasing appearance and handling qualities. Prior art has attempted to accomplish this quality by making a large number of individual mugs each having different characteristics however none have made these features interchangeable.
A search of the prior art did not disclose any patents that possess any of the novelty of the instant invention, however the following U.S. patents are considered related:
Letsch et al. in U.S. Pat. No. 4,754,888 discloses a carafe with an inner container surrounded by a casing. The inner container and the casing have an opening at the top which may be closed by a separate plug. The plug and opening in the container and casing are shaped such that it is possible to fill or empty the inner container while the plug is still in the opening. The plug and container both have mating grooves that provide opposed flow paths into and out of the container. The container also includes a basin around the top for receiving coffee from a coffee maker and the plug has openings to provide a flow path from the basin into the container interior.
Karp in U.S. Pat. No. 5,249,703 teaches a travel mug that includes a container and a lid in combination. The container has a handle and an annular lip that has an annulus capable of forming a seal with the top side of the annular lip. A cylindrical well in the lid has a vertical dividing wall such that the lid may be readily rotated by hand. The retaining arms extend from the underside of the lid and engage the underside of the annular lip to pull it into tight abutment. Diametrically opposed gaps in the lip act as passageway for the retaining arms. Similarly diametrically opposed notches in the lid align with the gaps to allow liquid to be poured from the container.
U.S. Pat. No. 5,918,761 issued to Wissinger is for an insulated container and cover combination that has an outer container shell terminating at an opening with a surrounding edge. An inner container shell is nested within the outer container shell and has an opening surrounded by a continuous edges in abutment with the surrounding edge. The inner container shell is spaced inwardly and is out of contact with the outer shell. A cover mounting assembly is attached to the outer shell adjacent to the opening. A single seal, made of elastomeric material, has a sealing surface disposed at the interface of the shells. Locating rings define the removable cover mounting assembly and locate the single sealing ring on the inner and outer shells.
For background purposes and as indicative of the art to which the invention is related reference may be made to the remaining cited design patents.
Coffee mugs are frequently used by many people and they are carried from place to place throughout the entire day becoming a rather personal item. Fairly recently stainless steel vacuum insulated or double wall coffee mugs have been introduced that have a very attractive appearance and they are popular in this country as well as throughout the world. Since these mugs have an advantage in there insulating qualities and are shaped pleasing to the eye, they can become a source of pride to the user. In an attempt to fill the needs of the public, many different shapes and styles of mugs have been developed and marketed. The problem of taste still remains, however, since what is attractive to one person may not look good to another.
Therefore a primary object of the invention is to have a mug with interchangeable accessories permitting the indivedual to select the combination of components that appears to be the best in their personal judgment. By marketing the accessory components separately individuals may not only select the combination that is pleasing in appearance to their taste but may choose a handle that has a good feel and is easy for the person to grip, therefore both the attractiveness and comfort may be simultaneously satisfied.
Another object of the invention is that the lid, handle and docking station may all be selected individually. The lid may have different color, surface finish and features such as a simple opening for pouring, a stopper for positive leak tight sealing or a convenient sliding cover. The handle includes a replaceable bracket that fits into a groove in the mug body which may have a number of shapes and colors with the handle itself varying in shape and size. The handle is attached to the bracket with a clip that blends into the shape of the handle and yet is removable per se. To assure a constant tight fit between the bracket and the mug body optionally a bracket may be selected, containing a number of radial grooves that are spaced around its periphery. The radial grooves retain small o-rings that compress and hold the bracket securely in place in applications where its use requires structural integrity.
An important object of the invention is directed to the ability of the mug to have a docking station attached to the bottom. The removable docking station has threads in the center to mate with mating threads in the coffee mug base. This permits the best of both worlds in that when the coffee mug is used on a flat surface the station permits it to be very stable since the base is large enough to spread the weight evenly over a liberal area and yet when the docking station is removed it fits easily into vehicle cup holders. The stability is extremely important as it is common to place a coffee mug in close proximity to keyboards, papers and work surfaces where coffee spills could be catastrophic. Further the configuration of mug is specifically sized to fit almost all conventional cup holders in a wide number of motor vehicles.
Still another object of the invention is that a retailer may stock a wide variety of accessories and replace only the well accepted components as required, not leaving the unpopular items overstocked as is the case with the complete individual mugs. Furthermore replacement of components may be easily made at a later date, if the user decides to update the mug or if breakage occurs.
These and other objects and advantages of the present invention will become apparent from the subsequent detailed description of the preferred embodiment and the appended claims taken in conjunction with the accompanying drawings.

Coffee mug with interchangeable accessories


Process data to a client is provided for process data to a client from a server in an Industrial Automation System. An incompletely determined and/or extensible request for process data from the client by the server is received. The structure and kind of process data to be sent to the client by a server application is determined. An XML type message of meta data being descriptive on structure and kind of the process data and the process data are generated. The XML type message is then sent to the client.

1. Field of Invention
The present invention relates to the field of providing process data to a client, such as for monitoring an Industrial Automation System.
2. Related Information
Remote monitoring and control of systems and processes have taken many forms. In the past, dedicated lines became the most common form of communication between a Control System and a remote location. Even today, many industry systems prefer to employ dedicated lines because they are secure, meaning that sensitive data, such as proprietary Industrial software code, is not at risk of being intercepted by competitors, and they are reliable, since there are less problems with connectivity and redundancy, for example, in such a direct connection.
For all of the advantages of the dedicated line, this method of connection has limited application because the Control System is, for one thing, not accessible from multiple locations. For this reason, amongst others, Industrial technologists have explored the use of Modems to make access to the Control System possible from different locations While Modems appear to solve the problem of remote connectivity, the actual reality is that these types of systems are much too unreliable, particularly in the Industrial field where information transmission is critical to a manufacturing process, for example. As a result, the practical use of Modems is generally restricted to downloading and uploading data files. In other words, providing any type of control function between locations is rather limited in this type of environment. Further, an end user generally required a customized interface to access the Control System.
With the explosion and subsequent growth of the Internet, the World Wide Web provides a promising, delivery platform that offers an opportunity for organizing and providing Internet data. The Web, a network of documents called sites or pages stored on server computers throughout the world, could provide access any Industrial system anywhere. Moreover, it is conceivable, for example, that data could be sent via hypertext links, for example, on a client server system. In this manner it is possible that a system could b provided that will, not only provide remote access for Industrial systems, but also give each end user the same degree of a user friendly interface with the same universal access to services on the Web.
However, the solution of remote access is not as easily implemented as that. Each Web page usually contains Text, i.e., some type of Multimedia offerings such as Graphic Images, Video, or Audio, and possible Hypertext Links to other documents. And that is an oversimplification of the media needed to support a client server Web Page. In addition, a Browser is required to allow a user to read the pages and interact with the choices associated with it. Normally, the Browser is a graphical software program that sends commands to the Internet Web site and displays whatever information is available on the page. While various Browser programs are commercially available from different manufacturers, it is too simplistic to expect that merely launching a Browser will solve all the connectivity problems and protocol issues required to, for example, access data and control remote Industrial Controllers.
A particular example that frustrates the use of the Internet Network for Critical Applications, such as in the Industrial Control Industry, is that the Internet is based on the fundamental concept of connecting multiple hubs together to form a network of access. Thus, a single Internet Server may handle thousands of general purpose computer connections at a moment through a single connection. The problem with this philosophy, while practical for broadband communication to remote sites, therefore, is that the Internet has no innate ability to differentiate traffic in terms of its purpose or the criticality of its data. Indeed, TCP/IP (Transfer Communication Protocol/Internet Protocol) is based on the Ethernet Protocol developed at Xerox Park, mostly to the credit of Robert Metcalfe, and Ethernet dices the data to be transmitted into packets that are often jammed together with packets from other sources of data to form a transmission stream. The Internet is no longer a network of computers that often shares a single transmission connection
To compound the problem, the Web may be interconnected or may be set up as a point to point link, such as in peer to peer communication. The Internet may, as well, involve both general purpose stations and specialized infrastructure components. For example, there are routers and firewalls that need to be dispensed with. These and other hardware and firmware issues need to be resolved.
Another fundamental principal of the Internet is that the type of personal computer or work station used by the end user to connect to the Web is typically of no regard to the Internet. Communication over the Internet and other networks accepts one of several types of protocols. Protocols such as Internet Protocol (IP) provide for file transfers, electronic mail, and other services. However, in specialized applications, such as Industrial Networks, it is possible that special provisions are required at the user end to interface with the user.
On the other side of the Industrial Connectivity issue, are the Programmable Logic Controllers. These are widely used in Industry and Process Control. Many manufacturers provide factory automation information using Microsoft Windows™ and other systems providing communication networking capabilities. However, these networks are usually slow, are not universally accessible and are limited to monitoring and data exchange.
Control may be implemented using such networks, but since the communication networks are non-deterministic, control is simply not in real time. Perhaps, specialized Industrial Network Systems using proprietary Fieldbus alternatives, but these can be very expensive. For one thing, conversion products are required to allow information carried over those networks to be visible on a general purpose network. Moreover, there are significant installation and other deployment costs associated with the existence of such intermediate devices. Firewalls between the Web server and the application are designed to solve problems of security and are not designed for high performance.
U.S. Pat. No. 6,061,603 discloses an Interface between an Industrial Control System and a Web Browser is known. This System is explained by making reference to FIG. 1.
FIG. 1 shows an overview block diagram of a typical system illustrating the relationship between a user 2 at a remote location and an Internet Web site 4 used for monitoring a Process Control System 6. The user 2 will have a personal computer (PC) 8 having a commercially available Browser 10, such as Netscape Communication's Navigator or Microsoft's Internet Explorer, installed for viewing the contents at the Web site 4 by a monitor 12.
The PC provides a remote Human-Machine Interface (HMI) to the process Control System 6. Various interconnection services are readily available to provide the physical and electrical interconnection from the PC to the Internet 14 itself. The Internet 14 is a collection of independent world wide communication networks that are interconnected to each other and function as a single connectionless entity.
Communication is based on a client-server basis, using a number of established protocols that allow for communication and file transfers between the client and the server. The most widely used protocol is Internet Protocol (IP).
The Web site 4 includes a network interface 16 having an unique Internet address 18, a server 20, and an application program 22. The server 20 acts as the HTTP interpreter which uses TCP in conjunction with IP, through TCP/IP stack 24 to interact with the network interface 16 and the application program 22.
This enables the data transfer between the application program 22 and the user 2 through the Internet 14. The application program provides data from the process Control System 6. This data can be used to monitor the control process by the user 2 at the remote location. The TCP/IP stack 24 enables data transfers over the Internet 14 between the user 2 and the Web site 4 as required for the various layers specified by the IP protocol.
The user 2 can connect to the Internet 14 using one of a number of Internet service providers and will enter the address of the Web site 4 when connected. The Web site 4 will display a home page which may contain text, some type of multimedia offerings such as graphic images, video, or audio, and possible hypertext links to other documents.
The Browser 10 will allow the user 2 to read the page and interact with the choices associated with it. The Browser 10 will send commands to the Web site 4 which will use the application program 22 to display whatever information is available from the process Control System 6. The Browser 10 functions as a remote human-machine interface or HMI control of the process Control System as will be detailed below.
Another prior art approach is OLE for Process Control (OPC).
At a high level, an OPC server is comprised of several objects: the server, the group, and the item. The OPC server object maintains information about the server and serves as a container for OPC group objects. The OPC group object maintains information about itself and provides the mechanism for containing and logically organizing OPC items.
The OPC Groups provide a way for clients to organize data. For example, the group might represent items in a particular operator display or report. Data can be read and written. Exception based connections can also be created between the client and the items in the group and can be enabled and disabled as needed. An OPC client can configure the rate that an OPC server should provide the data changes to the OPC client.
There are two types of groups, public and local (or 'private'). Public is for sharing across multiple clients, local is local to a client. There are also specific optional interfaces for the public groups. Within each Group the client can define one or more OPC Items.
The OPC Items represent connections to data sources within the server. An OPC Item, from the custom interface perspective, is not accessible as an object by an OPC Client. Therefore, there is no external interface defined for an OPC Item.
All access to OPC Items is via an OPC Group object that "contains" the OPC item, or simply where the OPC Item is defined. Associated with each item is a Value, Quality and Time Stamp. The value is in the form of a VARIANT, and the Quality is similar to that specified by Fieldbus.
Note that the items are not the data sources—they are just connections to them. For example, the tags in a Control System exist regardless of whether an OPC client is currently accessing them. The OPC Item should be thought of as simply specifying the address of the data, not as the actual physical source of the data that the address references.
An OPC application comprises COM (Communication Objects Model) or DCOM (Distributed Communication Object Model) objects and interfaces implemented by OPC servers.
The distributed component objects model (DCOM) is a protocol that enables software components to communicate directly over a network.
DCOM is an extension of the Component object Model (COM). COM defines how components and their clients interact. This interaction is defined such that the client and the component can connect without the need of any intermediary system component. In today's operating systems, processes are shielded from each other. A client that needs to communicate with a component in another process cannot call the component directly, but has to use some form of interprocess communication provided by the operating system. COM provides this communication in a transparent fashion: It intercepts calls from the client and forwards them to the component in another process. When client and component reside on different machines, DCOM replaces the local interprocess communication with a network protocol.
Network connections are inherently more fragile than connections inside a machine. Components in a distributed application need to be notified if a client is not active anymore, even—or especially—in the case of a network or hardware failure.
DCOM uses a pinging protocol to detect if clients are still active. Client machines send a periodic message. DCOM considers a connection as broken if more than three ping periods pass without the component receiving a ping message. If the connection is broken, DCOM decrements the reference count and releases the component if the count has reached zero. From the pont of view of the component, both the benign case of a client disconnecting and the fatal case of a network or client machine crash are handled by the same reference counting mechanism.
With DCOM, any component can be both a provider and a consumer of functionality. The same mechanism and features manage communication in both directions, making it easy to implement peer-to peer communication, as well as client/server interactions. In more recent work DCOM is replaced by a more loosely coupling between client and server through messages being sent from clients to server and vice versa.
Although message based communication is used a lack of flexibility and a lack of extensibility is a common disadvantage of the above described prior art approaches. For example if one of the software components is modified or if a new functionality is added the other components which interact with that component need to be adapted correspondingly.
It is therefore an object of the present invention to provide for an improved method of providing process data to a client, and to provide for a corresponding computer program product as well as improved server and client computers of an Industrial Automation System.
The object of the invention is solved by applying the features laid down in the respective independent claims. Preferred embodiments of the invention are given in the dependent claims.
The present invention is particularly advantageous in that it provides for a flexible, open and extensible communication means for client-server communication in an Industrial Automation System. This enables to modify and/or to add functionality to a server or client application without having to change or adapt other system components. This is made possible by the usage of mark up languages like XML or SGML or a similar mark up language as a transport and control format for the client-server communication.
In the following parts of this document the term "XML type message" is used for a document or text or message or parameter containing information formulated using a markup language like XML, SGML or alike. The term "XML-type" is used as an adjective to specifiy that a text, document, message or parameter is formatted according to a markup language like XML, SGML or other markup languges which enable a structuring of information.
The term "protocol" is used for a defined, specified or standardised sequence of messages, documents, function-calls or method-calls from a client to a server and vice versa.
Extensible means that a client or server can add additional data or meta data to a request or response without breaking compatibility with the protocol.
In accordance with a preferred embodiment of the invention the client computer directs a more or less unspecific request for runtime process data to a server of the Industrial Automation System. In response to this request the server determines the structure and the kind of process data to be provided to the client e.g. according to the request and the state or capabilities of the server.
A server application generates an XML type document with meta data being a description of the structure and/or meaning of the data being sent and containing the process data itself. This XML type document is sent to the client computer and is interpreted by an application program of the client computer. It is an important advantage that the content and/or structure of the data contained in the response message is not defined or is only partly defined by the requesting client. Rather, it is defined dynamically by the server both in structure as well as in content.
Furthermore it is possible, that the data contained in the response message and described by the meta data of the response message can itself be a text formulated using a markup language like XML and adding another level of flexibility and extendability.
In accordance with a further preferred embodiment of the invention the client computer makes the unspecific request mentioned above in the form of an XML type message.
In accordance with a further preferred embodiment of the invention the client computer makes a more specific request in the form of an XML type messsagewhich contains a subscription condition for process data.
For example if a subscription condition is met a refresh operation is to be performed and an XML type response message shall be sent. In principle any condition can be coded into the XML type message provided by the client to the server. Typical conditions are a certain cycle time for the data refresh or a change of a process parameter or parameters.
Alternatively or in addition in accordance with a preferred embodiment of the invention the XML type message from the client can also contain (meta) data which is a description or specification (e.g. a structure) of the process data to be provided by the server. This description or specification is extendible and open i.e. not fully specified in the specification of the access protocol. This enables that specific clients can formulate their own description or specification without braking the specification of the protocol and therefore being more flexible.
The server computer provides an acknowledgement to the client computer in which it informs the client if it can fulfil the specification contained in the request document provided by the client computer. If the contrary is the case this is also signalled to the client computer. In one embodiment the client computer modifies the specification contained in the XML document and sends a new XML document to the server computer until an acceptable XML document has been "negotiated" between the client and the server.
In accordance with a further preferred embodiment of the invention the server communicates to the client the specifications which it can support in form of a part of an XML type message. Based on this server information the client formulates the specifications contained in the XML type data request message. This can be done by selecting a subset of the specification supported by the server on the client side.
In accordance with a further preferred embodiment of the invention a certain set of specifications is standardized. Additional customer or manufacturer specific specifications can be added.

System, method & apparatus of providing process data to a client


Finely divided powdered rubbers containing filler which remain free-flowing even after exposure to mechanical stresses and to a process for the production thereof, in which the rubber powder is obtained in two precipitation steps, and to the use of these powders for the production of vulcanizable rubber compounds. The fillers used, which are both precipitated silicas and carbon blacks known in the rubber art, are surface-modifed by organosilicon compounds.

This application is based on German Patent Application DE 19816972.8 filed Apr. 17, 1998, the disclosure of which is incorporated herein by reference.
This invention relates to powdered rubbers containing fillers modified with organosilicon compounds, to a process for the production thereof and to the use thereof.
Numerous publications have appeared relating to the aim and purpose of using powdered rubbers as well as to possible processes for the production thereof.
The explanation for the interest in powdered rubbers is readily evident from the processing techniques used in the rubber industry, where rubber compounds are produced in time-consuming processes with elevated inputs of energy and labour. The principal reason for this is that the rubber raw material is in bale form.
Comminuting the bale, intimate mixing with fillers, mineral oil plasticizers and vulcanization auxiliaries proceeds in roll mills or in internal mixers in two or more processing stages. The compound is generally stored between the stages. Downstream from the internal mixers or roll mills are extruder/pelletizers or extruder/roller dies. The only way out of this highly complex rubber processing method is to use an entirely novel processing technology. The use of free-flowing rubber powders has accordingly long been discussed as such powders would make it possible to process rubber compounds simply and rapidly in the same manner as powdered thermoplastics.
DE-PS 2822 148 discloses a process for the production of a powered rubber containing fillers.
According to this patent, an aqueous filler emulsion is added to a rubber latex, rubber solution or an aqueous emulsion of a rubber and the desired rubber powder is precipitated. Variants for preventing the resultant filler contents being determined by grain size, as occurs when this process is used, have been filed and, as DE-PS 3723 213 and DE-PS 3723 214, are part of the prior art. According to DE-PS 3723213, in a two-stage process, a quantity of xe2x89xa750% of the filler is initially incorporated into the rubber powder particles. In the second stage, the remainder of the filler is applied onto the so-called basic rubber grains. This may be considered a variant of dusting as no bond is created between the filler and rubber.
However, as E. T. Italiaander has pointed out (presentation 151, technical conference of the Rubber Division of the ACS, Anaheim, Calif., 6-9 May 1997 (GAK 6/1997 (50) 456-464)), despite the bright future predicted in the Delphi Report (Delphi Report, xe2x80x9cKxc3xcnftige Herstellverfahren in der Gummiindustriexe2x80x9d, Rubber Journal, volume 154, no. 11, 20-34 (1972)) for powdered and pelletized rubbers and numerous attempts made by well-known polymer manufacturers from the mid 1970""s until the early 1980""s to produce powdered NBR, SBR/carbon black masterbatches and pelletized NR, the rubber bale remains the standard form in which rubber is supplied.
One disadvantage of known processes is firstly that a grinding operation is necessary in order to achieve a grain diameter of the filler particles of 10xcexcm, which is considered essential to the quality of the final product.
However, this requires not only elevated energy input but also results in damage to the filler structure which, together with the active surface area, is a significant parameter for its effectiveness in rubber applications.
Secondly, the handling properties of prior art products suffer in that the particles stick together during storage.
The object of the invention is accordingly to provide a powdered rubber containing filler which is easily handled, together with a process for the production thereof.
The present invention provides a powdered rubber in which a filler, at least a proportion of which is modified by organosilicon compounds, is solidly bonded to the rubber matrix by a precipitation process. No confusion is thus possible with only superficially or adhesively coated rubber particles.
The powders according to the invention exhibit a narrow size distribution which is shifted towards smaller particle sizes as is known from the prior art (Kautschuk+Gummi+Kunststoffe 7, 28 (1975) 397-402). This fact facilitates processing of the powders. Moreover, due to the production process, the filler content of the individual particles is not determined by grain size.
The powdered rubbers contain from 20 to 250 phr, in particular from 50 to 100 phr, of filler (phr: parts per hundred parts of rubber), of which at least a proportion has been surfaced-modified using organosilicon compounds of the formula (I) known in the rubber art. The following, individually or as mixtures, have proved to be suitable types of rubber: natural rubber, emulsion SBR having a styrene fraction of 10 to 50%, butyl/acrylonitrile rubber, butyl rubbers, terpolymers prepared from ethylene, propylene (EPM) and unconjugated dienes (EPDM), butadiene rubbers, SBR, produced using a solution polymerization process, having styrene contents of 10 to 25%, as well as 1,2-vinyl constituent contents of 20 to 55% oand isoprene rubbers, in particular 3,4-polyisoprene.
In addition to these stated rubbers, the following elastomers may be considered, individually or as mixtures:
carboxyl rubbers, epoxy rubbers, trans-polypentenamer, halogenated butyl rubbers, rubbers prepared from 2-chlorobutadiene, ethylene/vinyl acetate copolymers, epichlorohydrins, optionally also chemically modified natural rubber, such as for example epoxidized grades. Fillers which may be mentioned are the carbon blacks known from rubber processing and white fillers of a synthetic nature, such as, for example, precipitated silicas or natural fillers, such as, for example, siliceous chalk, clays etc.
Carbon blacks, as are generally used in rubber processing, are particularly suitable.
Such carbon blacks include furnace blacks, gas blacks and lamp backs having an iodine absorption value of 5 to 1000 m2/g, a CTAB value of 15 to 600 m2/g, a DBP absorption of 30 to 400 ml/100 g and a 24 M4 DBP value of 50 to 370 ml/100 g in a quantity of 5 to 250 parts, per 100 parts of rubber, preferably 20 to 150 parts, per 100 parts of rubber, more preferably 40 to 100 parts, per 100 parts of rubber.
Precipitated silicas known from the rubber art are also suitable.
These generally have an N2 surface area, determined using the known BET method, of 35 to 700 m2/g, a CTAB surface area of 30 to 500 m2/g, a DBP value of 150 to 400 ml/100 g. The product according to the invention contains these silicas in a quantity of 5 to 250 parts, preferably 20 to 100 parts, relative to 100 parts of rubber.
If white natural fillers are used, such as clays or siliceous chalks having an N2 surface area of 2 to 35 m2/g, they are used in a quantity of 5 to 350 parts, relative to 100 parts of rubber.
Filled rubber powders containing a mixture of silicas and carbon black are also suitable.
Unmodified fillers of the stated type are present in the rubber compounds claimed here only in addition to the fillers modified according to the invention. The proportion of the unmodified fillers depends upon the particular compound to be produced. In any event, the total filler content amounts to 20 to 250 phr. This quantity generally consists of 30 to 100%, preferably from 60 to 100%, of the modified fillers: silica and/or optionally carbon black. Surface-modification is generally performed using organosilicon compounds of the general formula
[R1nxe2x88x92(RO)3xe2x88x92nSixe2x80x94(Alk)mxe2x80x94(Ar)p]q[B1]xe2x80x83xe2x80x83(I),
R1n(RO)3xe2x88x92nSixe2x80x94(Alk)xe2x80x83xe2x80x83(II),
or
R1n(RO)3xe2x88x92nSixe2x80x94(Alkenyl)xe2x80x83xe2x80x83(III)
in which
B1: means xe2x80x94SCN, xe2x80x94SH, xe2x80x94Cl, xe2x80x94NH2 (if q=1) or xe2x80x94SXxe2x80x94 (if q=2)
R and R1: mean an alkyl group having 1 to 4 carbon atoms, branched or unbranched, a phenyl residue, wherein all residues R and R1 may each have the same or a different meaning, preferably an alkyl group,
R: means C1-C4 alkyl, C1-C4 alkoxy group, branched or unbranched,
n: means 0, 1 or 2,
Alk: means a divalent linear or branched hydrocarbon residue having 1 to 6 carbon atoms,
m: means 0 or 1
Ar: means an arylene residue having 6 to 12 C atoms
p: means 0 or 1, providing that p, m and n do not simultaneously mean 0,
x: means a number from 2 to 8,
Alkyl: means a monovalent linear or branched saturated hydrocarbon residue having 1 to 20 carbon atoms, preferably 2 to 8 carbon atoms,
Alkenyl: means a monovalent linear or branched unsaturated hydrocarbon residue having 2 to 20 carbon atoms, preferably 2 to 8 carbon atoms.
Examples of preferably used organosilanes are the bis(trialkoxysilyl-alkyl) oligosulfides which may be produced, for example, according to U.S. Pat. No. 3,842,111, such as bis-(trimethoxy-, triethoxy-, trimethoxyethoxy-, tripropoxy-, tributoxy-, tri-i-propoxy- and tri-i-butoxy-silyl-methyl) oligosulfides and specifically the di-, tri-, tetra-, penta-, hexasulfides etc., as well as bis-(2-trimethoxy-, triethoxy-, trimethoxyethoxy-, tripropoxy- and tri-n- and i-butoxy-ethyl) oligosulfides and in particular the di-, tri-, tetra-, penta-, hexasulfides etc., furthermore the bis-(3-trimethoxy-, triethoxy-, trimethoxyethoxy-, tripropoxy-, tri-n-butoxy- and tri-i-butoxysilyl-propyl) oligosulfides and again specifically the di-tri-, tetrasulfides etc. up to octasulfides, moreover the corresponding bis-(3-trialkoxy-silylisobutyl) oligosulfides, the corresponding bis-(4-trialkoxysilylbutyl) oligosulfides. Of these selected organosilanes of a relatively simple structure of the general formula I, those which are preferred are again the bis-(3-trimethoxy-, triethoxy- and tripropoxysilylpropyl) oligosulfides and specifically the di-, tri-, tetra- and pentasulfides, in particular the triethoxy compounds having 2, 3 or 4 sulfur atoms and mixtures thereof. In the general formula I, Alk means a divalent, linear or branched hydrocarbon residue, preferably a saturated alkylene residue having a linear carbon chain with 1 to 4 carbon atoms.
The silanes of the following structural formula are also particularly suitable
and the methoxy analogs thereof, which may be produced according to DE-AS 25 58191.
Nonionic, cationic and anionic surfactants are preferably used as surface-active substances. The concentration thereof in the suspension is 0.5 to 15 wt. %, preferably 0.5 to 5 wt. %, relative to the quantity of filler.
Examples of such surfactants are alkylphenol polyglycol ethers, alkyl polyglycol ethers, polyglycols, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkylbenzyltrimethylammomium salts, alkylbenzene sulfonates, alkyl hydrogen sulfates, alkyl sulfates.
In this manner, the entire quantity of organosilicon compounds necessary for the production of advantageous rubber compounds and vulcanizates may be incorporated by means of the modified filler. It is, however, possible to perform processes in which only a proportion of the organosilicon compounds are introduced in this manner and the remainder is added to the rubber compound in the conventional manner.
Such modified fillers are described, for example, in EP-B 0442 143, EP-B 0177 674 and in particular in pellet form in EP-A 0795 579 (white fillers) and in EP-B 0519 188 (carbon black).
Suitable bis(alkoxysilylalkyl)oligosulfanes have in particular proved to be those of the type of bis(trialkoxysilylalkyl)tetrasulfane and -disulfane.
The modified fillers known from the stated applications and patents and the organosilicon compounds mentioned therein are explicitly included in the present application as a constituent of the claimed compositions.
Apart from the above-stated fillers, the rubber powders according to the invention optionally contain known processing or vulcanization additives such as zinc oxide, zinc stearate, stearic acid, polyalcohols, polyamines, plasticizers, anti-aging agents to counter the action of heat, light or oxygen and ozone, reinforcing resins, flame retardants, such as for example Al(OH)3 and Mg(OH)2, pigments, various crosslinking chemicals and optionally sulfur in concentrations conventional in rubber processing.
The cross-section of the rubber powders according to the invention differs distinctly from that of products known from the prior art. The individual particles of the powdered rubber may consist of two zones which are intimately bonded together, concentrically enclose a center point and optinally have at least one of different filler content and different rubber content.
Depending upon the filler loading, filler particles are incorporated into the surface, such that the particles do not stick together, even under pressure, such as when several sacks are stacked.
This xe2x80x9cinertizationxe2x80x9d of the surface should not be confused with the known technique of dusting tacky powders with fillers. These only superficially adhering fillers are rapidly detached when exposed to mechanical stress, for example in a conveying plant or on transfer into silos. The sticking and agglomeration of the finely divided powders, which it is the intention to avoid, then occurs despite the dusting. Unlike the tacky particles superficially coated with fillers as flow promoters as are known from the prior art, according to the invention, filler particles are incorporated into the surface during the precipitation process for the production of the rubber powder. Depending upon the filler loading with one or more of the above-stated fillers, the advisable distribution between the interior of the particles and an outer zone associated therewith is established.
In a product having an elevated filler loading (xe2x89xa780 parts of filler per hundred parts of rubber), only 1 to 10 parts of this quantity of filler are incorporated in the outer grain zone. However, if the powdered rubber contains a total of  less than 80 parts of filler per hundred parts of rubber, 10 to 20 parts thereof are incorporated in the outer grain zone (peripheral zone), i.e. do not merely adhere by less effective adhesive forces.
The distribution of the filler within the particles and in the so-called peripheral zone generally varies between these contents.
The greater the total filler content, the less is the need to suppress the tackiness of the powder by an increased concentration of filler in the peripheral zone.
The present invention also provides a process for the production of finely divided, rubber powders containing filler by precipitation from aqueous mixtures which contain filler in the form of suspensions, water-soluble salts of a metal of groups IIa, IIb, IIIa and VIII of the periodic system of elements and a rubber latex or aqueous emulsions of a rubber solution by addition of an acid, which process is characterized in that xe2x89xa750 wt. % of the finely divided filler, at least a proportion of which has been surface-modified with an organosilicon compound according to the formulas (I), (II) or (III), are mixed with 0.1 to 6.5 parts by weight per 100 parts by weight of rubber of the stated water-soluble salts and a rubber latex or an aqueous emulsion of a rubber solution, the pH value of the mixture is reduced to a value in the range from 5.5 to 4.5 (first stage), the remainder of the finely divided filler in the form of a suspension is added and the pH value is reduced to approximately 3.2 (second stage), such that the rubber in the mixture is completely precipitated together with the filler.
The duration of the precipitation operation, which is determined by the pH value and the filler content, and the extent thereof may readily be determined by means of a series of measurements.
In the case of a rubber powder having an elevated filler loading (xe2x89xa780 parts of filler phr), 1 to 10 parts of this quantity will generally be used as the remaining proportion in the second stage of precipitation of the rubber powder.
If the rubber powder contains less than 80 parts of filler phr, for example a total of only 50 parts phr,  greater than 10 to 20 parts of this quantity will be introduced into the mixture in the form of a suspension before conclusion of the precipitation operation.
In this manner, the fillers are incorporated into the outer grain zone (peripheral zone) of the rubber powder.
These proportions of the filler are thus not applied externally onto the individual rubber particles (cf. DE-PS 37 23213), but are integrated into the surface of the rubber.
This distribution of the filler and the manner in which the fillers are bonded to the rubber composition bring about the elevated flowability of the powders according to the invention and prevent sticking during storage of the powder, without these properties being lost on exposure to mechanical stresses during conveying, transfer into silos etc.
The above-stated carbon blacks are used as fillers in finely divided (fluffy) form. These carbon blacks generally have an average grain diameter of 1 to 9xcexcm, preferably of 1 to 8xcexcm, before they are suspended. This facilitates dispersion, such that aqueous suspensions containing filler particles of an average particle diameter of distinctly less than 10xcexcm are obtained without elevated energy input. Precipitated silica may advantageously be used in the form of a filter cake which has been washed until salt-free.
Metal salts which may be used are those originating from elements of groups IIa, IIb, IIIa and VIII of the periodic system of elements. This division into groups corresponds to the former IUPAC recommendation (Periodisches System der Elemente, Verlag Chemie, Weinheim, 1985). Typical representatives are magnesium chloride, zinc sulfate, aluminum chloride, aluminum sulfate, iron chloride, iron sulfate, cobalt nitrate and nickel sulfate, wherein the salts of aluminum are preferred. Aluminum sulfate is particularly preferred.
The salts are used in a quantity of 0.1 to 6.5 parts by weight per 100 parts by weight of rubber. Acids suitable for establishing the defined pH values are primarily mineral acids, such as for example sulfuric acid, phosphoric acid and hydrochloric acid, wherein sulfuric acid is particularly preferred. However, carboxylic acids, such as for example formic and acetic acid, may also be used.
The quantity of acid is determined by the nature and quantity of the water-soluble metal salt, the filler, the rubber and the optionally present alkali metal silicate. This quantity may readily be determined by initial investigatory testing.
According to a preferred embodiment of the process according to the invention, up to 5 parts by weight per 100 parts by weight of rubber of silica (SiO2) are additionally used in the form of an alkali metal silicate solution, preferably as water glass having an Na2O:SiO2 molar ratio of 2:1 to 1:4. The alkali metal silicate solution may here be added both to the rubber component and to the filler suspension. It is preferably added to the rubber component, especially when the process is performed continuously.
The process according to the invention is generally performed as follows: first of all, a filler suspension is produced by dispersing a proportion, preferably xe2x89xa750%, of the filler present in the final product in water together with the metal salt and optionally the alkali metal silicate solution. The overall quantity of water is determined by the nature of the filler and the degree of digestion. In general, the water-insoluble constituents of the filler amount to approximately 6 wt. %. This value is not a binding restriction and both lower and higher quantities may be encountered. The maximum content is limited by the pumpability of the suspension.
The filler suspension produced in this manner is then intimately mixed, preferably in the presence of an emulsifier, with the rubber latex optionally containing alkali metal silicate solution or the aqueous emulsion of a rubber solution optionally containing alkali metal silicate solution. Known stirrers, such as for example propeller stirrers, are suitable for this purpose.
After mixing, a pH value in the range from 5.5 to 4.5 is first established while stirring is continued. This results in basic rubber grains having a constant filler content. The size of these basic grains is controlled by the selected quantity of metal salt in the range from 0.1 to 6.5 phr. Control is effected by the largest grain size being obtained with the lowest quantity of metal salt.
The remainder of the finely divided, optionally also modified white filler is added in the form of a suspension and the pH value is lowered to approximately 3.2.
The solids content of the latex used generally amounts to 20 to 25 wt. %. The solids content of the rubber solutions is generally 3 to 35 wt. %, that of the rubber emulsions generally from 5 to 30 wt. %.
These mixtures and the production thereof are known from the prior art.
When working up rubber powders having filler contents of xe2x89xa7100 phr, it is advantageous to reduce the pH value down to 2.5 before phase separation. An acid from the above-stated group of acids is advantageously used for this purpose.
The process according to the invention may be performed both discontinuously and continuously.
The precipitated rubber powder is advantageously separated by means of a centrifuge and then dried to residual water content of generally xe2x89xa61%, in particular in a fluidized bed drier.
During the production process, further processing and/or vulcanization additives may be added to the rubber powder according to the invention in a quantity conventional for vulcanizable rubber compounds or also a smaller quantity.
The rubber powders according to the invention are used for the production of vulcanizable rubber compounds. The constituents necessary for producing the compound may all be present in the rubber powder. Preferably, however, the powders contain rubber of the above-stated types and fillers. They may, however, also be mixed in a conventional manner with other rubbers and fillers, if this is necessary for the desired rubber compound.
It is possible according to the invention to produce a finely divided rubber powder which is free-flowing and which also remains free-flowing after exposure to mechanical stresses (for example conveying, packaging). By virtue of the finely divided nature thereof, no grinding or other comminution measures are required to obtain finely divided dispersions.
These then give rise to the finely divided rubber powders, which may readily be processed, and to vulcanizates having improved properties.

Powdered rubber containing modified fillers, process for the production thereof and use thereof