In a vacuum heat treating oven operating with hydrogen under pressure as the cooling medium, especially for the quenching of greatly heated metal workpieces (5), a method is provided for the automatic control of the progress of the process and for monitoring safety of operation. The housing (4) of the heat treating oven is for this purpose connected to gas inlet lines (9 and 10), one for the admission of the cooling gas and one for the admission of the flushing gas (H.sub.2 and N.sub.2, respectively), and also to a vacuum line (17) and to a gas outlet line (11) into each of which gas sensors (24, 39, 42) are inserted, which during the quenching process signal the gas concentration to a central processing unit (41) which also is connected to pressure sensors (19, 20) and a gas sensor (21) which issue additional signals concerning the gas pressures prevailing in each instant in the interior of the housing (4) or gas inlet line (10) and concerning the gas concentration in the environment of the oven to the central processing unit (41), which then in turn, according to preset programs, actuates the gas inlet and gas outlet valves (25, 30, and 18, 28, respectively) and turns on or off the motor-blower unit (12, 13) and the heating unit (15, 15a, . . . ).

Industrial furnaces of this kind are disclosed in German Patent 2844843. They are used especially so as to be able to harden parts of high-speed steel and other tool steels. They are also suitable, however, for other heat treatments, such as bright-annealing. Such a furnace consists of a hollow cylindrical steel housing with an opening front door which allows access to the heating chamber. The heating chamber is made from a steel jacket which is lined with a thermal insulation. On the bottom and on the roof the heating chamber is provided with a large opening for the passage of gas. These openings are closed during the heating and holding period by insulated shutters. In the cooling process cold gas which is circulated through the heating chamber flows around the charge in the heating chamber. The velocity of circulation and the degree of the recooling of the gas is controllable only by the design of the heat exchanger and blower belonging to the furnace.
A high gas velocity is what is required in order to achieve a rapid cooling of the charge. Only with a sufficiently fast heat removal is it possible to perform a hardening, for example. To achieve a rapid cooling of the charge, there exists, therefore, the need to circulate at a high velocity the quenching gas blown into the heating chamber.
The hardening of steels calls for a cooling of the workpieces from the austenitizing temperature (900.degree. C.) to room temperature at controlled rates. According to the type of steel, a heat removal is required that can be achieved only with certain environment media. The highest cooling rates are achieved with liquids. Gases have a lower thermal conductivity. By increasing the gas pressure and the circulating power it is possible to increase the heat removal to within the range of liquids. Disadvantages of liquid quenching is uncontrolled quenching, contamination of the surface with degradation products which call for complicated cleaning, and the expensive and difficult technology that is involved if the workpieces have to be annealed in a vacuum.
Gas quenching is usually performed with nitrogen gas, which except for helium and hydrogen produces the best heat removal. When nitrogen is used it is possible to raise the pressure to as much as 10 bar. With helium a further increase to 20 bar is possible. However, when these inert gases are used contamination in the oven is increased to a multiple of the pressure. Any further increase in the cooling ram in the gas is possible only by using hydrogen as the thermal transfer medium, since hydrogen has the highest thermal conductivity of all the gases, and also, due to its low density, it can be circulated with low power. With this gas all workpieces which heretofore have been quenched in liquids could be quenched in gas. An additional important advantage is the possibility of performing this quenching controlledly, which is not possible in liquids on account of Leidenfrost's phenomenon. Despite these evident advantages, high-pressure hydrogen quenching has not been achieved heretofore since the use of hydrogen at high pressure constitutes a considerable safety hazard.
It is therefore the object of the present invention to make safe practice of the process possible by a rational combination of known units of apparatus and to provide a procedure or flow sheet according to which this hydrogen quenching can be practiced. The sequence of the individual steps is to be selected such that at no time in the process can an explosive mixture form in the apparatus, and that, if some components fail, the development of a safety hazard can reliably be prevented.

Method and apparatus for the automatic monitoring of operating safety and for controlling the progress of the process in a vacuum heat-treatment oven


The gear consists of a four-shaft epicyclic gear, of which one shaft forms the input shaft which is in connection via an infinitely variable hydrostatic gear with the second shaft and of which the two remaining shafts represent connecting shafts which, in an extreme position of the hydrostatic gear, have the same speeds and behave during adjustment of the hydrostatic gear into the other extreme position in such a way that one becomes constantly slower and the other constantly faster, and which alternately act on the output shaft via gears of a gear group with following group shiftings. What is special is that the group shiftings make possible a multiple utilization of the gears of the gear group and that preparatory shifts for changing the group shifting provide the synchronization of idling gear parts, and that each gear change itself takes place at synchronous speeds, free from load and without tractive force interruption. Such gears require only small hydrostatic gears, have a particularly large transmission control range and favorable efficiencies. Its use in motor vehicles results in fuel savings and a superior acceleration behavior.

Gears according to the present invention are suitable for vehicles. They have a relatively large infinitely variable transmission control range and therefore allow operation of the internal combustion engine along a preferential characteristic in the family of characteristic curves. This may be, for example, the line of minimum fuel consumption or else a line for a good acceleration behavior. As such gears also have relatively good efficiencies, fuel can be saved. As there is no tractive force interruption, they also have a superior acceleration behavior. Their automatic operating principle contributes to the comfort of driving. The gear according to German Patent Specification 3,147,447 C2 or according to European Patent Specification 0,081,696 comes closest to the present invention.

Infinitely variable hydrostatic mechanical power shift gear with group shiftings


A poly cross linked phthalocyanine compound for a solar cell and ink composition comprising the same, and more particularly a poly cross linked phthalocyanine compound effective for use in a near infrared absorbent having a high absorption power in a near infrared wavelength from about 750 nm to about 1100 nm, wherein the poly cross linked phthalocyanine compound having structures according to the present inventive concept is sensitized to infrared region, although ruthenium-based compound used for existing dye-sensitized solar cells is sensitized to visible light region, such that the compound according to the present novel concept can be extended in wavelengths for use in solar cells to improve an energy conversion efficiency.

1. Field of the Invention
The following description relates generally to poly cross linked phthalocyanine compound for solar cell and ink composition comprising the same, and more particularly to poly cross linked phthalocyanine compound beneficial for use in a near infrared absorbent having a high absorption power in a near infrared wavelength from about 750 nm to about 1,100 nm.
2. Description of the Prior Art
Conventional solar cells convert light into electricity by exploiting the photovoltaic effect that exists at semiconductor junctions. In other words, the commercial solar cells absorb energy from visible light and converts excited charge carriers thereof to electric energy. At present, the main commercial solar cells are silicon-based solar cells. For a silicon-based solar cell, there are shortcomings in that high energy costs for material processing is required and many problems to be addressed such as environmental burdens and cost and material supply limitations are involved. For an amorphous silicon solar cell, there are also shortcomings in that energy conversion efficiency decreases when used for a long time due to deterioration in a short period.
Recently, many attempts have been undertaken to develop low-cost organic solar cells, whereby development of one particular type of solar cell which is a dye-sensitized solar cell (DSSC) is accelerated that generally uses an organic dye to absorb incoming light to produce excited electrons.
The dye-sensitized solar cells have advantages over silicon-based solar cells in terms of simplified processing steps, low fabrication cost, transparency and pleochroism. The dye-sensitized solar cells can be fabricated from flexible substrates to function as cells of mobility and portability.
The dye-sensitized solar cells have lower energy (photoelectric) conversion efficiency over that of the silicon-based solar cells such that a wide range of researches are briskly under way to enhance the energy conversion efficiency. In order to improve the energy conversion efficiency, extension of wave length up to infrared regions is being waged with great concern. It is known that the energy bandgap (eV) for use in solar cells must exceed 1.4 eV (electron volt).
Meanwhile, phthalocyanine compound used as a dye in electrodes for solar cells has advantages such as high transmittivity relative to visible light, excellent selective absorption power in the near infrared region, high heat resistance, high weatherability and high thermotolerance, so that the phthalocyanine compound has a wide range of applications including ink and fields where a predetermined wave length is absorbed or interrupted.
A variety of technologies involving the phthalocyanine compound has been disclosed. For example, phthalocyanine compound and manufacturing method thereof are described in Korea Patent Laid-Open Publication No. 10-528155, the phthalocyanine compound being expressed in the following Formula 1,
where, M1 and M2 independently represent selections from non-metals, metals, metal oxides, and metal halides and may be same or different each other. R1 to R16 respectively represent a hydrogen atom, a halogen atom, a hydroxyl, an amino group, a hydroxysulfonyl group, an aminosulfonyl group, an alkyl group, an alkyl group which may have substituents of a 1˜20 carbon numbers, SR17, SR18, OR19, NHR20 or NHR21, selections which may be respectively the same or different, and where, R17 is a phenyl group which may have substituents, an alkyl group or a 1˜20C alkyl group, R18 is a phenyl group which may have a 1˜20C alkoxy group, R19, R20 are respectively a phenyl group which may have a substituent, an arylalkyl group or a 1˜20C alkyl group, R21 is a 1˜20C alkyl group which may have a substituent, and n is an integer of 0˜3.
The phthalocyanine compound having a structure of the afore-mentioned Formula 1 which has a phthalic anhydride and a urea, a metal salt or a metal chloride may interrupt an inflow of oxygen, and may be obtained by reaction at a high temperature using solvent of a high boiling point.
In this regard, it is therefore desirable to keep working on the compound showing an absorption power at a wider scope of a near infrared region.

Poly cross linked phthalocyanine compound for solar cell and ink composition comprising the same


In a system for optimizing natural gas production in response to real-time variations in wellbore parameters, a PLC or other wellsite intelligence technology is used to monitor liquid and gas production from the wellbore under friction-loaded conditions. Using baseline production data obtained during production tests, the PLC determines and initiates the appropriate operating mode for the wellbore to optimize a selected production criterion to suit measured wellbore parameters. The operating mode either a continuous clean-out mode, in which gas is continuously injected into the wellbore to control liquid loading, or an intermittent clean-out, in which liquid loading is regulated by intermittent gas injection. In preferred embodiments, the system uses bladder-type control valves having upstream and downstream solenoids, to control production tubing flow rate within a range between upper and lower set points.

Natural gas is commonly found in subsurface geological formations such as deposits of granular material (e.g., sand or gravel), coal, shale, or porous rock. Production of natural gas from these types of formations typically involves drilling a well a desired depth into the formation, installing a casing in the wellbore (to keep the well bore from sloughing and collapsing), perforating the casing in the production zone (i.e., the portion of the well that penetrates the gas-bearing formation) so that gas can flow into the casing, and installing a string of tubing inside the casing down to the production zone. Gas can then be made to flow up to the surface through a production chamber, which may be either the tubing or the annulus between the tubing and the casing.
Formation liquids, including water, oil, and/or hydrocarbon condensates, are generally present with natural gas in a subsurface reservoir. For reasons explained in greater detail hereinafter, these liquids must be lifted along with the gas. In order for this to happen, one of the following flow regimes must be present in the well:
Pressure-Induced Flow
                In a pressure-induced flow regime, the formation pressure (i.e., the pressure of the fluids flowing into the well) is greater than the hydrostatic pressure from the column of fluids (gas and liquids) in the production chamber. In other words, the formation pressure is sufficient to lift the liquids along with the gas. Pressure-induced flow occurs in wells producing from reservoirs having a non-depleting pressure; i.e., where the reservoir pressure is high enough that production from the reservoir results in no significant drop in formation pressure. This type of flow regime is common in reservoirs under water flood or having an active water drive providing pressure support. Conventional gas lift technology may be used to enhance flow in a pressure-induced flow regime by lightening the hydrostatic weight of total fluids in the production chamber.        Pressure-induced flow is most commonly associated with wells that are primarily oil-producing wells, and is rarely associated with primarily gas-producing wells.Velocity-Induced Flow        This type of flow occurs with gas reservoirs having a depleting pressure, and it is common in most gas reservoirs and all solution-gas-driven oil reservoirs. The present invention is concerned with velocity-induced flow, a general explanation of which follows.        In order to optimize total volumes and rates of gas recovery from a gas reservoir, the bottomhole flowing pressure should be kept as low as possible. The theoretically ideal case would be to have a negative bottomhole flowing pressure so as to facilitate 100% gas recovery from the reservoir, resulting in a final reservoir pressure of zero.        When natural gas is flowing up a well, formation liquids will tend to be entrained in the gas stream, in the form of small droplets. As long as the gas is flowing upward at or above a critical velocity (or "VCR"—the value of which depends on various well-specific factors), the droplets will be lifted along with the gas to the wellhead, where the gas-liquid mixture may be separated using well-known equipment and methods. In this situation, the gas velocity provides the means for lifting the liquids; i.e., the well is producing gas by velocity-induced flow.        The critical velocity VCR for a given wellbore will be dependent on a number of factors which may vary from one wellbore to the next, and which are subject to change over the life of the wellbore. Such factors may include, but are not necessarily limited to, reservoir pressure, flow line pressure, liquid production rate, liquid composition, gas composition, and wellbore design.
Formation pressures in virgin reservoirs of natural gas tend to be relatively high. Therefore, upon initial completion of a well, the gas will commonly rise naturally to the surface by velocity-induced flow provided that the characteristics of the reservoir and the wellbore are suitable to produce stable flow (meaning that the gas velocity at all locations in the production chamber remains equal to or greater than the critical velocity, VCR—in other words, velocity-induced flow). Typically these wells will flow with excess velocity (i.e., significantly greater than VCR), resulting in friction between the flowing fluids and the production chamber.
As gas reserves are removed, the formation pressure drops continuously, resulting in reduced fluid velocities in the wellbore. Lower fluid velocity provides the benefit of reduced friction loading; however, it also diminishes the water-lifting capability of the wellbore. Once the gas velocity has become too low to lift liquids, the liquids accumulate in the wellbore, and the well is said to be "liquid loaded". This accumulation of liquids results in increased bottomhole flowing pressures and reduced gas recoveries. In this situation, continued gas production from the well requires the use of mechanical methods and apparatus in order to remove liquids from the wellbore and to restore stable flow.
In summary, gas wellbores are subject to two types of loading: (1) friction loading and (2) liquid loading.
Friction loading is caused by fluid flowing up the production tubing at high velocity, and results in restricted formation drawdown. Friction loading typically will not "kill" a well (i.e., completely halt the production of well fluids); however, it can significantly restrict production. The remedy or solution for friction loading is to reduce fluid velocities—e.g., by reducing gas flow rates (thus reducing gas velocity), or by increasing production chamber size while maintaining flow rates (thus reducing gas velocity).
Liquid loading is caused by insufficient fluid velocity up the production tubing. Like friction loading, liquid loading results in restricted formation drawdown. Liquid loading will eventually result in the well being killed. Any time a wellbore is "killed" (i.e., its production of well fluids is stopped) due to excessive liquids, considerable costs must be incurred to correct the problem and restore production from the well.
As discussed above, liquid loading can be reduced or eliminated by increasing fluid flow velocity to produce velocity-induced flow conditions. However, increased flow velocity also promotes increased friction loading. Current wellbore design methods typically provide excess flow velocity (i.e., significantly higher than VCR) to eliminate liquid loading and ensure that the well does not die. The resultant friction loading is accepted as the lesser of two evils.
In order to maintain long-term stable production rates from any gas well, the first priority is to ensure that the wellbore is substantially free from accumulation of liquids. If liquids production is substantial, any accumulation of liquids in the wellbore must be removed, either continuously or intermittently depending on the rate of accumulation. In cases where liquids are removed on an intermittent basis, the well would alternate between production and clean-out cycles, with the clean-out cycle beginning when accumulated liquids reach an undesirable level, and with gas production necessarily being stopped during the clean-out cycle.
In accordance with the preceding discussion, it can be appreciated that production optimization for a gas well requiring removal of liquids can be achieved by keeping the fluid velocity as close as practically possible to the well's critical velocity, in order to prevent accumulation of liquids while minimizing friction loading.
U.S. Pat. No. 6,991,034 and corresponding International Application No. PCT/CA2004/000478 teach methods and apparatus for enhancing natural gas well productivity by maintaining a velocity-induced flow regime, thus providing for continuous removal of liquids from the well and preventing or mitigating liquid loading and friction loading of the well. In accordance with U.S. Pat. No. 6,991,034, a supplementary pressurized gas is injected into a first (or injection) chamber of a gas well as necessary to keep the total upward gas flow rate in a second (or production) chamber of the well at or above a minimum flow rate needed to lift liquids within the upward gas flow. A cased well having a string of tubing may be considered as having two chambers (namely, the bore of the tubing, and the annulus between the tubing and the casing), and either of these chambers can serve as the first (or injection) chamber, with the other serving as the second (or production) chamber.
The invention of U.S. Pat. No. 6,991,034 provides for a gas injection pipeline, for injecting the supplemental gas into the injection chamber, and further provides a throttling valve (also referred to as a "choke") for controlling the rate of gas injection, and, more specifically, for maintaining a gas injection rate sufficient to keep the gas flowing up the production chamber at or above a set point established with reference to a critical flow rate. Strictly speaking, the critical flow rate is a well-specific gas velocity above which liquids will not drop out of an upward-flowing gas stream (as previously explained). However, the critical flow rate for a given wellbore may also be expressed in terms of volumetric flow based on the critical gas velocity and the cross-sectional area of the production chamber.
As explained in U.S. Pat. No. 6,991,034, the critical flow rate for a particular well may be determined using methods or formulae well known to those skilled in the art. A "set point" (i.e., minimum rate of total gas flow in the production chamber) is then selected, for purposes of controlling the operation of the choke. The set point may correspond to the critical flow rate, but more typically will correspond to a value higher than the critical flow rate, in order to provide a margin of safety. Once the well has been brought into production, an actual total gas flow rate in the production chamber is measured. If the measured total gas flow rate (without gas injection) is at or above the set point, the choke will remain closed, and no gas will be injected into the well. However, if the measured total gas flow rate is below the set point, the choke will be opened so that gas is injected into the injection chamber at a sufficient rate to raise the total gas flow rate in the production chamber to a level at or above the set point.
Gas productions systems as taught in U.S. Pat. No. 6,991,034 may be referred to as fixed-velocity production systems.
U.S. Pat. No. 7,275,599 (and corresponding International Application No. PCT/CA2004/001567) teach methods and apparatus whereby the intake pipeline running between the production chamber of a natural gas well and the suction inlet of an associated wellhead compressor is completely enclosed within a vapour-tight jacket of natural gas under positive pressure (i.e., greater than atmospheric pressure). Being enclosed inside this "positive-pressure jacket", the intake pipeline is "blanketed" with positive-pressure gas and therefore is not exposed to the atmosphere at any point. This allows gas to be drawn into the compressor through the intake pipeline under a negative pressure (i.e., lower than atmospheric pressure), without risk of air entering the intake pipeline should a leak occur in the pipeline. If such a leak occurs, there would merely be a harmless transfer of gas from the positive pressure jacket into the intake pipeline. Should a leak develop in the positive pressure jacket, gas therefrom will escape into the atmosphere, and entry of air into the positive pressure jacket will be impossible. As taught in U.S. Pat. No. 7,275,599, these teachings can be readily adapted for use in conjunction with wells producing gas under velocity-induced flow conditions in accordance with methods taught in U.S. Pat. No. 6,991,034.
Extensive scientific research has developed a number of flow correlations that predict downhole velocities in flowing wellbores. The oil and gas industry relies on these correlations to predict critical flow rates, and attempts to design production tubing strings such that fluid velocities will equal or exceed predicted critical velocities. However, experience with wellbore modeling indicates that some wells are capable of lifting liquids at velocities considerably below the predicted critical velocity, and some wells can become liquid loaded despite producing at fluid velocities well above the predicted critical velocity.
The ideal solution for optimizing a wellbore producing with a fixed-velocity lift system is to determine whether it requires continuous liquids removal, or whether it would be more optimally produced at velocities below critical with reduced friction loading, accompanied by intermittent removal of liquids. In other words, a well that liquid-loads over a period of (for example) ten days would benefit from intermittent clean-outs, while a well that loads over a period of one hour would require continuous liquids removal.
For the foregoing reasons, there is a need for systems and methods for:                automatically determining whether continuous or intermittent clean-out of liquids is the optimal production mode for a given wellbore, having regard to wellbore and formation properties;        automatically determining the optimum duration of production and clean-out cycles for wells utilizing an intermittent clean-out system;        automatically determining the optimal production chamber (e.g., either the tubing or the casing annulus), and switching fluid flow in the wellbore accordingly; and        automatically determining actual critical velocities for producing wellbores, and for maintaining the set point substantially equal to the actual critical velocities for wellbores utilizing a continuous clean-out system.
Any system or method directed to the foregoing needs will necessarily entail use of flow control devices. Control valves of various types are commonly used to control the flow of both liquid and gaseous fluids. Flow control may be achieved using a control valve in combination with a controller (i.e., a device incorporating a processor and a memory, such as but not limited to a pneumatic controller or a programmable logic controller (PLC)) that compare one or more flow variables (such as but not limited to flow rate, pressure, and temperature) against pre-established values (or "set points"). In response to corresponding signals from the controller, the control valve either opens (partially or fully) or closes as necessary to maintain the flow variable(s) in question at the appropriate set point(s).
As used in this patent document, the term "control valve" may be understood as referring to either a discrete control valve or to a control valve assembly that incorporates a control valve, according to the context. A typical conventional control valve assembly (such as, for example, the Fisher® D (globe-style) or DA (angle-style) valve) includes a valve body, internal valve trim ("valve trim" being a term readily understood by persons skilled in the art), and a valve actuator. A conventional control valve assembly will commonly be provided in conjunction with additional accessories such as (but not limited to) positioners and proportional controllers. These accessories provide a means to enter a control set point for the control valve. Each configuration for a conventional control valve typically provides a relatively narrow capacity range for a given set of process conditions. Due to this narrow capacity range and the inherent complexity of the control valve, maintenance and design must be done by professional instrumentation personnel. As a result, conventional control valves are relatively expensive to purchase and maintain.
Most if not all control valves commonly used in the natural gas industry are pneumatically driven, and their operation typically results in the venting of methane gas to the atmosphere. In the past, this undesirable operational characteristic was considered tolerable in view of the reliability of such pneumatically-actuated control valves. However, with the increasing focus on reducing greenhouse gas emissions and improving system efficiencies, there is an increasing incentive to find environmentally-friendly alternative methods and apparatus for controlling fluid flow and pressure.
Electric actuators can be used to eliminate the venting of gas. However, electric actuators are comparatively expensive and have significant electrical power requirements, with correspondingly high operating costs.
For the foregoing reasons, it is desirable to have a comparatively simple and inexpensive control valve that can control fluid flow effectively under a broad range of process conditions with minimal power consumption and absolutely no external venting of gas. Such a control valve would ideally be serviceable by any ordinarily-skilled field personnel using comparatively inexpensive non-precision parts.
One known type of non-venting control valve is a bladder-type valve such as the "Sur-Flo"™ control valve manufactured by Sur-Flo Meters & Controls Ltd., of Calgary, Alberta, Canada. A typical bladder-type valve of the Sur-Flo™ type has a valve core comprising a pair of frustoconical sections configured much like common pails, each having a solid base at its small-diameter end and with its large-diameter end being open, but with its conical sidewall having a plurality of perforations. The two frustoconical sections are coaxially arranged inside a generally cylindrical valve housing, with their bases in close juxtaposition. A generally cylindrical elastomer sleeve (or "bladder") is disposed within the valve housing, completely encircling the frustoconical sections, and a pressure port is provided through the cylindrical sidewall of the valve housing.
When this valve assembly is installed in a fluid flow line, and when there is no external pressure acting on the bladder through the pressure port, fluid can flow freely into the first frustoconical section and out through that section's sidewall perforations into the space between the frustoconical sections and the bladder, and then into the second frustoconical section through its sidewall perforations. However, if sufficient external fluid pressure is applied against the bladder via the pressure port (such as from a "volume bottle" or "expansion bottle" of well-known type, or from another pressure source), the bladder will contract against the frustoconical sections, sealing off their sidewall perforations, and thus preventing fluid flow through the valve assembly. At lower external fluid pressures, the bladder will restrict but not completely prevent fluid flow through the valve. Accordingly, flow through the valve can be incrementally controlled across the range between the fully-closed and fully-open position by varying the fluid pressure applied against the bladder via the pressure port, with the degree of flow restriction being roughly proportional to the external pressure acting against the bladder.
The bladder-type control valve is a comparatively simple non-venting valve that provides a wide range of flow control options under any process conditions. This valve is considerably less expensive than more complex control valves commonly in use, and it is readily serviceable by ordinarily skilled field personnel. This type of valve has proven durability and is very commonly used as a fixed-set-point back-pressure valve.
What is needed is an inexpensive adaptation of the bladder-type control valve that converts the simple fixed-set-point control valve to a variable-set-point control valve, thereby providing control of both flow and pressure. Such operational capabilities will be particularly beneficial in control valves used in conjunction with methods and apparatus for optimizing production in natural gas wells, but will be beneficial for purposes of other control valve applications as well.


A fluid-handling system capable, in various embodiments, of storing, mixing, and dispensing fluids, and also regulating the flow of fluids. The system includes a cartridge having a non-expandable housing, and a bladder within the housing. In some variations, a drive-liquid is introduced into a region between the housing and the bladder, which causes fluid contained within the bladder to dispense. In some other variations, the drive-liquid is introduced into the bladder, which causes the bladder to expand and expel fluid that is contained with the housing.

The present invention relates generally to fluid-handling systems, and more particularly to devices or systems that are capable of formulating, storing, dispensing, or regulating the flow of fluids.
The development, production and sales of countless industrial and consumer products involve fluid-handling operations (e.g., flow regulation, dispensing fluids, storing fluids, mixing fluids, etc.). Fluid-handling systems are used to perform these operations.
One application for fluid-handling systems is in the production of xe2x80x9cformulations.xe2x80x9d Formulations are produced by the physical combination of two or more fluids or fluidized ingredients. Formulation ingredients are often liquid, or otherwise liquefied, so that they flow under appropriate conditions.
To create a formulation, the ingredients are usually transported (e.g., pumped, etc.) to a receiver, where they are physically (and sometimes chemically) combined, typically in precise amounts. For some formulations, this xe2x80x9ccombiningxe2x80x9d operation occurs in a production facility; for others, it occurs at the point of sale by a retailer, etc. Once a formulation is produced, it is typically packaged and then, at an appropriate time, dispensed for use. For some applications, an ability to dispense a precise amount of the formulation is required; for some others, it""s not.
Many different products are properly characterized as xe2x80x9cformulationsxe2x80x9d under the definition provided above. Examples include personal-care products (e.g., shampoo, perfume, etc.), household cleaning products ((e.g., liquid dishwashing detergents and clothes-cleaning detergents, etc.), foods (e.g., cream cheese, ice cream, margarine, etc.), industrial products (e.g., engine oil, lubricants, industrial cleaners, etc.), adhesives (e.g. glues, resins, etc.), paints and coatings, pharmaceutical products, and electronics xe2x80x9cchemicalsxe2x80x9d (e.g., solder masks, etch resist masks, etc.), to name but a few.
The products listed above, which are but a small subset of the universe of formulated products, vary widely as to their rheological properties. Furthermore, formulation applications present substantial application-to-application differences in the relative amounts of ingredients and in the amount of product being formulated. Compare, for example, commercial-scale production of a food (e.g., mayonnaise, etc.) versus a point-of-sale apparatus for formulating paints in one-quart to five-gallon batches (e.g., for home-owners, etc.). Additionally, the specific fluid-handling operations being performed will vary (e.g., transporting vs. mixing vs. dispensing, etc.). Consequently, fluid-handling systems and components that are used for the production of formulations are implemented in a wide variety of application-specific designs and configurations.
By way of example, for some formulation applications, fluid-handling systems include special pumps that are used to pressurize liquid for transport or dispensing. In some other applications, syringes are used to deliver product. In yet further applications, pipettes are coupled to systems capable of pressurizing fluids for dispensing. Often, fluid-handling requires emulsification or mixing of ingredients. Some fluid-handling systems are available as xe2x80x9cbottle-topxe2x80x9d dispensers that directly couple to a bottle of liquid to dispense the liquid contained therein. But some other systems are quite complicated and include their own fluid reservoirs, control systems, etc.
Some formulation ingredients and formulated products present special difficulties for fluid-handling systems. For example, formulation ingredients (or formulated products) that are high-viscosity liquids, high-solids-concentration liquid suspensions, non-Newtonian fluids, and the like cause problems for rotating equipment, such as pumps. Among other problems, it is difficult to control the flow rate of such materials. Consequently, special pumps are required.
Furthermore, as implied above, some prior-art fluid-handling systems are equipment-intensive. In particular, these systems typically include one fully-controllable pump for each ingredient in the formulation. Such systems are often relatively expensive. And prior-art fluid-handling systems often require substantial maintenance. This maintenance includes servicing the rotating equipment (e.g. pumps, etc.) to keep it operational and cleaning the system regularly to prevent clogging. Clogging is particularly likely when the formulation ingredients are high-viscosity liquids, polymerizable materials, and high-solids-concentration suspensions. Additionally, to avoid contamination, these systems must be cleaned whenever the formulation is changed.
The art would therefore benefit from a fluid-handling system that, among another attributes, has a configuration or structure that is less application-sensitive than prior-art systems. In particular, the fluid-handling system should possess at least some of the following attributes:
Suitable for use with products over a wide range of rheological properties (e.g., low viscosity to high viscosity, etc).
Suitable for use over a wide range of capacity (e.g., flow rate, amount of ingredients, etc).
Not as maintenance-intensive as prior-art fluid-handling systems.
Suitable for use in a variety of applications (e.g., storage, mixing, dispensing, etc.).
A fluid-handling system that avoids some of the problems of the prior art is disclosed. Some fluid-handling systems in accordance with the present invention are generally suitable for use with products over a wide range of rheological properties, can accommodate wide variations in the amount of fluid being handled, are less maintenance-intensive than some prior art systems, and are capable of performing a variety of fluid-handling functions.
In various embodiments, a fluid-handling system in accordance with the illustrative embodiment of the present invention is capable of performing one or more of the following functions, among any others: receiving and storing one or more fluids, keeping stored fluids separate from one another, mixing two or more fluids to formulate a product, accurately dispensing fluid, and regulating a flow of fluid.
The specific configuration of a fluid-handling system in accordance with the illustrative embodiment is dependent, to some extent, on its intended use. More particularly, certain features or elements are included in some variations of the system but not in some others, as a function of the intended use of the system. Certain elements are, however, basic to all variations of a fluid-handling system in accordance with the present invention. In particular, basic to all variations is a cartridge that has a bladder and a substantially non-expandable housing. The bladder is disposed within the housing.
A fluid-handling system in accordance with the illustrative embodiment optionally includes a drive-liquid delivery device. This device is capable, in accordance the illustrative embodiment, of delivering liquid (xe2x80x9cdrive-liquidxe2x80x9d) to a region that is within the housing but outside of the bladder. When sufficiently pressurized, the drive-liquid exerts a force against the bladder that results in the expulsion any fluids that are contained within the bladder. In other words, the fluid is indirectly xe2x80x9cpumpedxe2x80x9d such that it does flow through the drive-liquid delivery device. Consequently, if a change is made in the fluid (e.g., new ingredients, etc.), it is accommodated, in some embodiments, by changing the bladder. Generally far less cleaning is required to accommodate a change in fluid than for most prior-art liquid handling systems.
In a variation of the illustrative embodiment, drive-liquid is delivered to the interior of the bladder, rather than outside of the bladder. As the bladder expands, it expels any fluids that are contained with the housing (but outside of the bladder). While this variation might entail more maintenance than the illustrative embodiment, it has certain advantages, as described later in this specification.
In some variations of the illustrative embodiment, fluid-handling systems include multiple (i.e., two or more) cartridges that are coupled to one another. In some of those variations, the bladders are also coupled to one another so that fluid can pass from one bladder to the next. Multi-cartridge arrangements are particularly well suited for conducting experimentation, such as, for example, permuting the order in which ingredients are combined to produce a formulation. Multi-cartridge arrangements are also well adapted to mixing fluids by moving them back and forth between adjacent cartridges, possibly through an orifice structured to promote mixing. As suits the requirements of a particular application, multiple cartridges can be configured in serial or parallel fashion, etc.
In some variations of the illustrative embodiment, an optional control system is coupled to a cartridge, enabling the cartridge to be used as a flow regulator. In such variations, a sensor (e.g., a force sensor, etc.) senses a flow rate, pressure, etc., of a fluid that is flowing out of the cartridge. The sensor generates and outputs, to a controller, a signal that is representative of the flow rate (or pressure, etc.) of the fluid. The controller compares that signal to a set point. Based on a deviation between the sensor output signal and the set point, the controller generates and outputs a control signal. The control signal is output to a final control element, such as the drive-liquid delivery device. The control signal alters the operation of the drive-liquid delivery device, etc., as appropriate, to adjust the flow of fluid from the cartridge to a desired rate.
Large changes in the amount of fluid being handled are accommodated, in some variations of the illustrative embodiment, by changing bladder size. In some other variations, the cartridge itself (i.e., housing and bladder) is replaced by a different cartridge (more suitably sized for the changed quantity of fluid).
These and other variations of a fluid-handling system in accordance with the illustrative embodiment of the present invention are illustrated in the Drawings and described further in the Detailed Description section of this specification.

Fluid-handling systems and components comprising a bladder pump, a methods therefor


A method and apparatus for enabling users of a packet network service, e.g., a VoIP network service, who live in the same household and share a common phone number to have individualized user identifiers to be transmitted along with their call setup messages are disclosed. For example, each user in the household would have a different user identifier which they could retrieve from an endpoint device immediately before dialing the phone number when they want to place a call that would transmit their personalized user identifier in the call setup message.

Caller party identification for incoming calls is currently linked to the name of the subscriber on the billing account for traditional phone service. Given that multiple parties can share a single account, and an individual person can place a call from any phone line, the transmitted caller id information does not always convey the true identity of the calling party.
For example, members of a household often share a common phone number. When individuals in a household place a call using a phone tied to the common phone number, the calling party identification that gets transmitted in the call setup message is the name associated with the registered billing party. Other users of the same phone number will not be able to use their individual calling name information when making a phone call.
Therefore, a need exists for a method and apparatus for enabling multiple calling name identifiers for individual phone numbers.

Method and apparatus for providing multiple calling name identifiers


An inexpensive dielectric coolant for fuel cell stacks. The present invention is directed to a fuel cell, a fuel cell system, and methods for cooling a fuel cell and fuel cell system. The fuel cell is configured to react fuel with oxygen to generate an electric current and at least one reaction product and comprises an anode, an anode flowpath, a cathode, a cathode flowpath, and a membrane disposed between the anode and the cathode. At least one coolant flowpath is fluidly decoupled from the anode and cathode flowpaths and d fines a coolant isolation manifold. The coolant isolation manifold includes a fluid dielectric coolant that comprises a kerosenic hydrocarbon, which can be kerosene or an emulsion of water in kerosene. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 C.F.R. xc2xa71.72(b).

The present invention relates generally to liquid cooled fuel cells and, more particularly, to a fuel cell, a fuel cell system, and methods for cooling a fuel cell or fuel cell system.
Fuel cells rely on hydrogen oxidation and oxygen reduction to produce electrical energy. The byproduct of these catalytic reactions is water. Thermodynamically, the oxidation of hydrogen fuel at an anode and the reduction of oxygen at a cathode, both the anode and the cathode located within a fuel cell, should give a cell potential of about 1.23 V. However , the actual measured value is typically around 1 V. This difference in cell voltage is due primarily to the slow kinetics of the cathode, which amounts to an almost 200 mV loss in cell voltage. The result of this loss in cell voltage is an expression of excess heat within the fuel cell. The removal of such excess heat is essential to increasing the useful lifetime of the fuel cell components.
As multiple fuel cells are arranged in a stack to increase electrical output, heat generation becomes significantly high. Consequently, in order to remove such excess heat, a coolant is employed that has a high heat capacity and which is physically stable at a temperature between about xe2x88x9240xc2x0 C. and about 140xc2x0 C. Aqueous coolants used with conventional combustion engine vehicles fall within this range and typically comprise a mixture of ethylene glycol and water. However, the design of today""s fuel cell stacks requires that the coolant be non-conducting (dielectric). If the coolant has a significant conductivity, it will lead to a variety of conductive coolant-induced stack problems including shunt currents that reduce fuel efficiency, gas evolution (O2 and H2) in the header area creating increased pressure within the fuel cell stack requiring venting, coolant degradation, and oxygen degradation of stack components including coating blistering and corrosion acceleration.
Known in the art is the use of ion exchange resins with deionized water to rid of impurities in the coolant and maintain its low conductivity. However, the use of deionized water is limited in areas that experience severe winter weather where temperatures can reach xe2x88x9240xc2x0 C. At this temperature, water freezes and would not be a suitable coolant or the stack.
Also known is the use of a pure dielectric coolant (i.e., Therminol(copyright)-D available from Solutia Inc., St. Louis, Mo.). As a pure dielectric, the fluid does not allow current to flow through the header area of the stack. However, the cost as well as the incompatibility of the coolant with gaskets currently employed in fuel cell stacks makes the use of such pure dielectric coolants impractical.
Accordingly, the present inventors have recognized a need for improvements in liquid coolant technology for fuel cell stacks.
The present invention meets the above-mentioned need by providing an inexpensive and readily available dielectric coolant for fuel cell stacks. Although the present invention is not limited to specific advantages or functionality, it is noted that because the coolant is a dielectric and does not allow for any ionic transport, it does not affect the stack components, and does not allow for any performance loss caused by shunt currents on the header area of the stack. Consequently, corrosion inhibitors need not be added to prohibit O2 degradation of fuel cell components. Although the heat capacity of the dielectric coolant of the present invention is slightly less than aqueous-based coolants, the present coolant has a low kinematic viscosity which enables it to be pumped at higher flow rates to remove waste heat without an appreciable increase in parasitic pumping power. Moreover, the relatively high boiling point of the dielectric coolant enables operating the fuel cell stack and coolant loop at higher temperatures (xcx9c140xc2x0 C.), increasing the capacity to exhaust heat from the radiator to the environment.
In one embodiment, the present invention provides a fuel cell configured to react fuel with oxygen to generate an electric current and at least one reaction product. The fuel cell comprises an anode flowpath, an anode, a cathode flowpath, a cathode, a membrane disposed between the anode and the cathode, and at least one coolant flowpath. The al ode flowpath is configured to route the fuel through at least a portion of the fuel cell. The anode is in fluid communication with the anode flowpath and upon which a catalytic reaction with the fuel is configured to take place. The cathode flowpath is configured to route the oxygen through at least a portion of the fuel cell. The cathode is in fluid communication with the cathode flowpath and upon which a catalytic reaction with the oxygen is configured to take place. The membrane is disposed between the anode and the cathode such that electrolyte communication is established therebetween during operation of the fuel cell. The coolant flowpath is fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold that includes a fluid dielectric coolant, which comprises a kerosenic hydrocarbon.
In another embodiment, the present invention provides a fuel cell configured to react fuel with oxygen to generate an electric current and at least one reaction product. The fuel cell comprises an anode flowpath, an anode, a cathode flowpath, a cathode, a membrane disposed between the anode and the cathode, at least one coolant flowpath, and a recirculation assembly. The anode flowpath is configured to route the fuel through at least a portion of the fuel cell. The anode is in fluid communication with the anode flowpath and upon which a catalytic reaction with the fuel is configured to take place. The cathode flowpath is configured to route the oxygen through at least a portion of the fuel cell. The cathode is in fluid communication with the cathode flowpath and upon which a catalytic reaction with the oxygen is configured to take place. The membrane is disposed between the anode and the cathode such that electrolyte communication is established therebetween during operation of the fuel cell. The coolant flowpath is fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold that includes an inlet, an outlet, and a fluid dielectric coolant, which comprises a kerosenic hydrocarbon. The recirculation assembly comprises a recirculation flowpath, a pump, and a radiator. The recirculation flowpath fluidly connects the coolant isolation manifold inlet and the coolant isolation manifold outlet.
In still another embodiment, the present invention provides a fuel cell system comprising a fuel cell stack comprising a plurality of fuel cells, wherein each fuel cell is configured to react fuel with oxygen to generate an electric current and at least one reaction product. Each fuel cell comprises an anode flowpath, an anode, a cathode flowpath, a cathode, a membrane disposed between the anode and the cathode, and at least one coolant flowpath. The anode flowpath is configured to route the fuel through at least a portion of each fuel cell. The anode is in fluid communication with the anode flowpath and upon which a catalytic reaction with the fuel is configured to take place. The cathode flowpath is configured to route the oxygen through at least a portion of each fuel cell. The cathode is in fluid communication with the cathode flowpath and upon which a catalytic reaction with the oxygen is configured to take place. The membrane is disposed between the anode and the cathode such that electrolyte communication is established therebetween during operation of each fuel cell. The coolant flowpath is fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold that includes a fluid dielectric coolant, which comprises a kerosenic hydrocarbon.
In yet another embodiment, the present invention provides a fuel cell system comprising a fuel cell stack comprising a plurality of fuel cells, wherein each fuel cell is configured to react fuel with oxygen to generate an electric current and at least one reaction product. The fuel cell comprises an anode flowpath, an anode, a cathode flowpath, a cathode, a membrane disposed between the anode and the cathode, at least one coolant flowpath, and a recirculation assembly. The anode flowpath is configured to route the fuel through at least a portion of each fuel cell. The anode is in fluid communication with the anode flowpath and upon which a catalytic reaction with the fuel is configured to take place. The cathode flowpath is configured to route the oxygen through at least a portion of each fuel cell. The cathode is in fluid communication with the cathode flowpath and upon which a catalytic reaction with the oxygen is configured to take place. The membrane is disposed between the anode and the cathode such that electrolyte communication is established therebetween during operation of each fuel cell. The coolant flowpath is fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold that includes an inlet, an outlet, and a fluid dielectric coolant, which comprises a kerosenic hydrocarbon. The recirculation assembly comprises a recirculation flowpath, a pump, and a radiator. The recirculation flowpath fluidly connects the coolant isolation manifold inlet and the coolant isolation manifold outlet.
In still yet another embodiment, the present invention provides a method for cooling a fuel cell comprising providing a fuel cell configured to react fuel with oxygen to generate an electric current and at least one reaction product. The method further comprises configuring the fuel cell to include an anode, a cathode, and a membrane disposed between the anode and the cathode; configuring an anode flowpath and a cathode flowpath to route the fuel and oxygen to the anode and the cathode, respectively; and, configuring at least one coolant flowpath to be fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold, and the coolant isolation manifold includes a fluid dielectric coolant, which comprises a kerosenic hydrocarbon.
In still yet another embodiment, the present invention provides a method for cooling a fuel cell comprising providing a fuel cell configured to react fuel with oxygen to generate an electric current and at least one reaction product. The method further comprises configuring the fuel cell to include an anode, a cathode, and a membrane disposed between the anode and the cathode; configuring an anode flowpath and a cathode flowpath to route the fuel and oxygen to the anode and the cathode, respectively; and, configuring at least one coolant flowpath to be fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold, and the coolant isolation manifold includes an inlet, and outlet, and a fluid dielectric coolant, which comprises a kerosenic hydrocarbon. In addition, the method comprises configuring a recirculation assembly comprising a recirculation flowpath so that the recirculation flowpath fluidly connects the coolant isolation manifold inlet and the coolant isolation manifold outlet, which recirculation assembly further includes a pump and a radiator, circulating the fluid dielectric coolant throughout the coolant isolation manifold, whereby the fluid dielectric coolant draws heat from the fuel cell to produce a heated fluid dielectric coolant, and circulating the heated fluid dielectric coolant from the coolant isolation manifold outlet to the radiator via the recirculation flowpath, whereby the heated fluid dielectric coolant is cooled and returned to the coolant isolation manifold inlet.
In still yet another embodiment, the present invention provides a method for cooling a fuel cell system comprising providing a fuel cell stack comprising a plurality of fuel cells, wherein each fuel cell is configured to react fuel with oxygen to generate an electric current and at least one reaction product. The method further comprises configuring each fuel cell to include an anode, a cathode, and a membrane disposed between the anode and the cathode; configuring an anode flowpath and a cathode flowpath to route the fuel and oxygen to the anode and the cathode, respectively; and, configuring at least one coolant flowpath to be fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold, and the coolant isolation manifold includes a fluid dielectric coolant, which comprises a kerosenic hydrocarbon.
In still yet another embodiment, the present invention provides a method for cooling a fuel cell system comprising providing a fuel cell stack comprising a plurality of fuel cells, wherein each fuel cell is configured to react fuel with oxygen to generate an electric current and at least one reaction product. The method further comprises configuring each fuel cell to include an anode, a cathode, and a membrane disposed between the anode and the cathode; configuring an anode flowpath and a cathode flowpath to route the fuel and oxygen to the anode and the cathode, respectively; and, configuring at least one coolant flowpath to be fluidly decoupled from the anode flowpath and the cathode flowpath. The coolant flowpath defines a coolant isolation manifold, and the coolant isolation manifold includes an inlet, and outlet, and a fluid dielectric coolant, which comprises a kerosenic hydrocarbon. In addition, the method comprises configuring a recirculation assembly comprising a recirculation flowpath so that the recirculation flowpath fluidly connects the coolant isolation manifold inlet and the coolant isolation manifold outlet, which recirculation assembly further includes a pump and a radiator, circulating the fluid dielectric coolant throughout the coolant isolation manifold, whereby the fluid dielectric coolant draws heat from the fuel cell to produce a heated fluid dielectric coolant, and circulating the heated fluid dielectric coolant from the coolant isolation manifold outlet to the radiator via the recirculation flowpath, whereby the heated fluid dielectric coolant is cooled and returned to the coolant isolation manifold inlet.

Inexpensive dielectric coolant for fuel cell stacks


In a method for producing a power semiconductor arrangement, an insulation carrier with a top side, a metallization, and a contact pin with a first end are provided. The metallization is attached to the top side and a target section of the metallization is determined. After the metallization is attached to the top side of the insulation carrier, the first end of the contact pin is pressed into the target section such that the first end is inserted in the target section. Thereby, an interference fit and an electrical connection are established between the first end of the contact pin and the target section of the metallization.

In many power semiconductor arrangements, the internal and external electrical connection of the arrangement is realized by means of electrically conductive contact pins. However, soldering or welding such contact pins to a circuit carrier of the arrangement is cumbersome and often requires manual work. Therefore, there is a need for an improved power semiconductor arrangement and for an improved method for producing a power semiconductor arrangement.

Power semiconductor arrangement and method for producing a power semiconductor arrangement


The present invention relates to a fluorine-containing diene compound represented by the following formula I, and to a polymer thereof. In the formula, each of R1 to R7 is independently a hydrogen atom, a chlorine atom, a fluorine atom, or an alkyl group having a carbon number of 1 to 5 which may be substituted by a fluorine atom, k is 0 or 1, and at least one of R1 to R7 is a hydrogen atom.

A polymer containing a fluorine atom in the main chain and obtained from a fluorine-containing unsaturated compound as a raw material monomer has an excellent balance of various properties such as low refractive index, low dielectric constant, water repellency/oil repellency, heat resistance, chemical resistance, chemical stability and transparency and is used in a wide variety of fields such as electric/electronic materials, semiconductor materials, optical materials and surface-treating agents.
Among others, in the case where a fluorine-containing compound as a raw material monomer is a fluorine-containing diene compound having two carbon-carbon double bonds and having a total number of carbon atoms and oxygen atoms intervening between the carbon-carbon double bonds of 2 or 3 (carbon atoms constituting the carbon-carbon double bonds are not counted; in the case of having a branched (branching) structure, carbon atoms and oxygen atoms contained in the branch are not counted), cyclopolymerization is possible and a polymer having a 5-membered or 6-membered ring structure in the main chain is primarily produced. Such a fluorine-containing diene compound has heretofore been usually synthesized in multiple steps.
Non-Patent Literature 1 states that perfluoroallyl fluorosulfate (CF2═CFCF2OSO2F) is obtained from hexafluoropropene (CF2═CFCF3) in one step. It is reported that various compounds can be synthesized from the perfluoroallyl fluorosulfate.

Fluorine-containing diene compound, fluorine-containing polymer, and methods for producing same


A thin, lightweight solar cell utilizes front contact metallization. Both the front light receiving surface of the solar cell and the facing surface of the cover glass are recessed to accommodate this metallization. This enables the two surfaces to meet flush for an optimum seal.

U.S. Pat. No. 4,295,002 to Chappell et al discloses a dual surface solar cell to provide additional efficiency. These surfaces are composed of different materials with different radiation absorption characteristics. The cover glass is affixed to one side of the cell and the contact metal to the other. The metal contact could be on the front depending on the orientation of the cell.
U.S. Pat. No. 4,589,191 to Green et al is directed to a high efficiency solar cell with mounted metallization. The cover glass is referred to an antireflective coating, and it is illustrated as grooved to meet the top metallization.
U.S. Pat. No. Bl 4,610,077 to Minahan et al describes a wraparound metallization for a solar cell. Front metallization is effectively achieved by this method.
U.S. Pat. No. 4,694,115 to Lillington et al is concerned with a solar cell with front surface metallization. There are two antireflective coatings, both of which fall beneath the front contact metallization.
U.S. Pat. No. 4,824,489 to Cogan et al illustrates a typical prior art arrangement for a thin solar cell. U.S. Pat. No. 4,854,975 to Krause describes both P-type and N-type layers exposed on the front surface of a solar cell making front contact metallization possible.

The United States of America as represented by the Administrator of the National Aeronautics and Space Administration