def rpm(self, vol_per_rev):
        """Return the pump speed required for the reactor's stock of material
        given the volume of fluid output per revolution by the stock's pump.

        :param vol_per_rev: Volume of fluid pumped per revolution (dependent on pump and tubing)
        :type vol_per_rev: float

        :return: Pump speed for the material stock, in revolutions per minute
        :rtype: float
        """
        return Stock.rpm(self, vol_per_rev, self.Q_stock()).to(u.rev/u.min)
Return the pump speed required for the reactor's stock of material
        given the volume of fluid output per revolution by the stock's pump.

        :param vol_per_rev: Volume of fluid pumped per revolution (dependent on pump and tubing)
        :type vol_per_rev: float

        :return: Pump speed for the material stock, in revolutions per minute
        :rtype: float