Fluid Pump and Method of Pumping a Fluid

Abstract

Embodiments of the invention provide dry gaseous fluid pump apparatus comprising: a fluid inlet and a fluid outlet; at least one pump body having an internal wall defining an internal pump chamber thereof; a compression member provided within the pump chamber; and valve means being operable selectively to allow fluid to be drawn from the fluid inlet and into the pump chamber when at least a portion of the compression member is translated in a first direction and to be exhausted from the pump chamber through the fluid outlet when said at least a portion of the compression member is translated in a second direction opposite the first, the valve means being arranged to be actuated by actuator means under the control of control means to perform at least one selected from amongst the functions of allowing fluid to be drawn from the fluid inlet into the pump chamber and allowing fluid to be exhausted from the pump chamber through the fluid outlet, the apparatus comprising a linear drive assembly operable to drive the at least a portion of the compression member to and fro within the pump chamber.

1 . Dry gaseous fluid pump apparatus comprising:
 a fluid inlet and a fluid outlet;   at least one pump body having an internal wall defining an internal pump chamber thereof;   a compression member provided within the pump chamber; and   a valve being operable selectively to allow fluid to be drawn from the fluid inlet and into the pump chamber when at least a portion of the compression member is translated in a first direction and to be exhausted from the pump chamber through the fluid outlet when said at least a portion of the compression member is translated in a second direction opposite the first, the valve being arranged to be actuated by an actuator under the control of a controller to perform at least one selected from amongst the functions of allowing fluid to be drawn from the fluid inlet into the pump chamber and allowing fluid to be exhausted from the pump chamber through the fluid outlet,   the apparatus comprising a linear drive assembly operable to drive the at least a portion of the compression member to and fro within the pump chamber.   
     
     
         2 . Apparatus as claimed in  claim 1  comprising an inlet valve through which fluid may be drawn into the pump chamber from the fluid inlet and an outlet valve through which fluid may be expelled from the pump chamber to the fluid outlet, each valve having a closure member operable to open or close the valve thereby to allow or prevent flow of fluid therethrough, wherein at least one of the inlet and outlet valves are actuated by the actuator. 
     
     
         3 . (canceled) 
     
     
         4 . Apparatus as claimed in  claim 2  wherein both the inlet valve and the outlet valve are actuated by the actuator. 
     
     
         5 . Apparatus as claimed in  claim 4  wherein the inlet and outlet valves are provided with respective different closure elements. 
     
     
         6 . Apparatus as claimed in  claim 4  wherein the inlet and outlet valves share a common closure element, the closure element being operable by the actuator to move between a first position in which the inlet valve is open and the outlet valve is closed and a second position in which the inlet valve is closed and the outlet valve is open. 
     
     
         7 . (canceled) 
     
     
         8 . Apparatus as claimed in  claim 1  wherein the actuator comprises at least one drive unit. 
     
     
         9 . Apparatus as claimed in  claim 8  wherein the inlet and outlet valves are provided with respective different closure elements, and wherein the actuator comprises a first drive unit operable to open and close the inlet valve and a second drive unit operable to open and close the outlet valve. 
     
     
         10 . (canceled) 
     
     
         11 . Apparatus as in  claim 8  wherein the drive unit comprises a piezo-electric drive. 
     
     
         12 . Apparatus as in  claim 8  wherein the drive unit comprises an electromagnetic drive. 
     
     
         13 . Apparatus as in  claim 8  wherein the drive unit comprises an electric motor. 
     
     
         14 . Apparatus as claimed in  claim 1  wherein the valve is provided in a head portion of the apparatus facing the compression member. 
     
     
         15 . Apparatus as claimed in  claim 1 , further comprising sensor that is configured to sense a position of the compression member, the controller being arranged to control the actuator responsive to the position of the compression member. 
     
     
         16 . Apparatus as claimed in  claim 15  wherein the sensor comprises at least one selected from amongst an optical sensor, a magnetic sensor, an acoustic sensor and an electromagnetic radiation sensor. 
     
     
         17 . Apparatus as claimed in  claim 15  arranged to sense a position of the compression member by detection of a signal generated by a transmitter of the sensor and received by a receiver of the sensor following reflection from the compression member, the signal being one selected from amongst an optical signal, an acoustic signal and an electromagnetic signal. 
     
     
         18 . (canceled) 
     
     
         19 . Apparatus as claimed in  claim 1  comprising a sensor yhat is configured to sense a pressure of fluid in the pump chamber, the controller being arranged to control the actuator responsive to the pressure of fluid in the pump chamber. 
     
     
         20 . Apparatus as claimed in  claim 1  wherein the at least a portion of the compression member is arranged to reciprocate between a first position proximate the valve and a second position distal the valve. 
     
     
         21 . Apparatus as claimed in  claim 20  wherein the controller is operable to control the valve to allow a flow of fluid into the pump chamber from the fluid inlet when the at least a portion of the compression member moves from the first position towards the second position thereby to reduce a magnitude of a force required to so move the compression member. 
     
     
         22 . Apparatus as claimed in  claim 20  wherein the controller is operable to control the valve to allow a flow of fluid into the pump chamber from the fluid inlet when the at least a portion of the compression member is substantially at the first position thereby to reduce a magnitude of a force required to so move the compression member. 
     
     
         23 . Apparatus as claimed in  claim 2  wherein the controller is arranged to open the outlet valve as the at least a portion of the compression member moves from the second position to the first position and to close the outlet valve when the at least a portion of the compression member is substantially at the first position thereby to increase the amount of fluid exhausted through the outlet valve. 
     
     
         24 . (canceled) 
     
     
         25 . Apparatus as claimed in  claim 1  wherein the linear drive assembly comprises a coupling rod coupled to the compression member, the drive assembly being arranged to drive the coupling rod to and fro in a substantially straight line along a direction coincident with a longitudinal axis of the coupling rod. 
     
     
         26 . Apparatus as claimed in  claim 1  wherein the drive assembly comprises a piezoelectric drive portion. 
     
     
         27 . Apparatus as claimed in  claim 1  wherein the drive assembly comprises an electromagnetic drive portion. 
     
     
         28 . Apparatus as claimed in  claim 1  wherein the linear drive assembly is in fluid communication with the compression member, and
 wherein the linear drive assembly is provided in a vacuum-tight package whereby it is sealed from an environment external to the apparatus. 
 
     
     
         29 - 30 . (canceled) 
     
     
         31 . Apparatus as claimed in  claim 1  wherein the apparatus is a vacuum pump. 
     
     
         32 - 33 . (canceled) 
     
     
         34 . An apparatus as claimed in  claim 31  wherein the vacuum pump comprises at least first and second pump apparatus, wherein respective compression members of the first and second pump apparatus are arranged to reciprocate along a common axis, and
 wherein the respective compression members are arranged to reciprocate either in phase or in anti-phase with respect to one another. 
 
     
     
         35 - 38 . (canceled) 
     
     
         39 . A method of dry pumping a gaseous fluid by means of dry pumping apparatus comprising:
 drawing fluid through a fluid inlet into a pump chamber via a valve when at least a portion of a compression member is translated in a first direction and exhausting fluid from the pump chamber through a fluid outlet via the valve when said at least a portion of the compression member is translated in a second direction opposite the first,   the method comprising actuating the valve by an actuator under the control of controller to perform at least one selected from amongst the functions of allowing fluid to be drawn from the fluid inlet via the valve into the pump chamber and allowing fluid to be exhausted from the pump chamber via the valve through the fluid outlet,   the method further comprising driving the at least a portion of the compression member to and fro within the pump chamber by a linear drive assembly.   
     
     
         40 . (canceled)