Patent Publication Number: US-6663360-B1

Title: Fluid injection pump with internal air actuator valve

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to fluid pumps. More specifically, the invention is a pneumatic pump which includes an air actuator valve mounted in the pump&#39;s reciprocating piston head. 
     2. Description of Related Art 
     Prior art pneumatic pumps require an air actuator to control piston cycling. The air actuator is usually mounted on the exterior of the pump and comprises a conglomerate of various parts (screws, diaphragms, spools, o-rings, etc.) which make for a relatively complicated structure that is prone to break down and difficult to repair. A pump which eliminates the need for an externally mounted, complicated air actuator would certainly be a welcome addition to the art. 
     The relevant art of interest cited herein describes various fluid pumps and actuator valves, but none discloses the present invention. For example, U.S. Pat. No. 5,297,469 (Raymond) describes a power actuator wherein a piston functions as a control valve element. The piston&#39;s position is utilized to generate a signal which triggers a reversing valve. This arrangement employs complicated fluid circuitry. 
     U.S. Pat. No. 3,963,383 (Hill) discloses an air-driven pump. A shuttle valve for controlling the admission of pressurized air is mounted to the exterior of the pump. 
     U.S. Pat. No. 4,645,431 (Spencer et al.) shows a piston-driven hydraulic pump wherein the valve for controlling the entrance of pressurized air is mounted to the exterior of the pump. 
     U.S. Pat. No. 4,120,314 (Lissau), U.S. Pat. No. 4,242,941 (Wilden et al.) and U.S. Pat. No. 6,102,363 (Eberwein) are all drawn to actuator valve structure. The patentees do not contemplate mounting the valves in the head of a piston. 
     None of the above inventions and patents, taken either singly or in combination, is seen to disclose an injection pump and actuator valve as will subsequently be described and claimed in the instant invention. 
     SUMMARY OF THE INVENTION 
     The pneumatic fluid injection pump of the instant invention is preferably operated by air. It should be noted that other suitable gases may be utilized if desired. A needle valve which controls the supply of air is disposed in the pump body cap. An air actuator valve is disposed in the piston head. When the pump is in a starting position, the air valve actuator is in a closed position to prevent any passage of air. To start the pumping action, compressed air is fed directly through the pump body cap into the pump body cylinder chamber. The amount of air fed is controlled by the gap between the needle valve and a needle valve seat which is also located in the pump body cap. The air enters the body cylinder chamber and drives the piston and plunger rod through the fluid end of the pump. This action forces the liquid fluid out through a discharge check valve, and simultaneously closes a suction check valve. When the piston is pushed on its pumping stroke, a spring on the air actuator valve contacts a surface of the body cylinder chamber to cause the air actuator valve to open and release the trapped air through the air actuator valve so that the air can exit the pump. This action allows the spring around the piston and plunger to release and return the piston and plunger to the starting position in the body cylinder chamber. This return action causes the liquid to be drawn through the suction check valve into the pump, while simultaneously closing the discharge check valve. When the piston reaches its starting position in the body cylinder chamber, the air actuator valve returns to a closed position, thus allowing the cycle to repeat numerous times per second. The pneumatic injection pump having this internal air valve actuator injects the liquid by positive displacement caused by the reciprocating piston. 
     Accordingly, it is a principal object of the invention to provide an internal air actuator valve in a fluid injection pump. 
     It is another object of the invention to provide an internal air actuator valve incorporated in the head of a piston. 
     It is a further object of the invention to provide an air actuator valve having a compressive spring to elevate the valve upon reaching the end of a piston stroke. 
     Still another object of the invention is to provide a temporary holding element in the piston head to secure the elevated actuator valve. 
     It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which are inexpensive, dependable and fully effective in accomplishing their intended purposes. 
    
    
     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially cross-sectioned, plan view of the pneumatic fluid or chemical fluid injection pump incorporating the air actuator device in the piston head according to the present invention. 
     FIG. 2A is a partially cross-sectioned, plan view of a pneumatic fluid or chemical injection pump having an internal air actuator valve, which valve is in a closed position according to the present invention. 
     FIG. 2B is a partially cross-sectioned, plan view of a pneumatic fluid or chemical injection pump having an internal air actuator valve, which valve is in an open position according to the present invention. 
     FIG. 3 is a side elevational view of the air actuator valve. 
     FIG. 4 is an exploded, partially cross-sectioned, elevational view of the air actuator valve and the piston head with the locking system according to the present invention. 
     FIG. 5 is an exploded, partially cross-sectioned, elevational, view of the discharge check valve device according to the present, invention. 
     FIG. 6 is an exploded, partially cross-sectioned, elevational partial view of the suction check valve device according to the present invention. 
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Attention is first directed to FIGS. 1-2B wherein the pump and air actuator valve of the present invention is generally indicated at  10 . The pump includes a pump body cap  12  mounted to the proximate end of a pump body cylinder  14  with set screws  16  or the like. O-rings  18  are utilized to insure a fluid-tight seal between cap  12  and body  14 . A piston head  20  is mounted for reciprocating movement within a chamber  14   a  of body  14 . A compression spring  21  (FIGS. 2A-2B) functions to bias piston head  20  toward the proximate end of body  14 . Piston head  20  incorporates conventional piston stem  20   a  and plunger  20   b.  Packing nut  22  and packing seal  24  function to seal chamber  14   a  from a chamber  14   b , which chamber  14   b  is disposed in the distal end of body  14 . A discharge conduit  26  having a check valve therein is in fluid communication with chamber  14   b  and extends in a first direction from the distal end of body  14 . A suction conduit  28  is also in fluid communication with chamber  14   b  and extends in a second direction from the distal end of body  14 . Although the suction conduit and the discharge conduit are shown as extending in different directions (ninety degrees apart), it is contemplated that an additional opening can be provided in the wall of the body. As illustrated, the opening for the suction conduit may be plugged such that both discharge and suction conduits are positioned in substantially the same horizontal or vertical plane. Conduit  28  is provided with a check valve therein. A needle valve  30  provided with a compression spring  30   a  is disposed in cap  12  for controlling the flow of compressed air entering cap  12  via opening  12   a . An air actuator valve  40  is disposed in piston head  20  for controlling the flow of air from chamber  14   a  as will be explained below. 
     As best viewed in FIGS. 3 and 4, air actuator valve  40  includes a hollow tubular member  42  having four openings  44  (only one is shown) in the peripheral wall thereof. Member  42  is disposed for telescopic movement within an opening formed in piston head  20 . An O-ring  46  is fitted into a groove at the top of member  42 . A compression spring  48  is fitted to one end of member  42 . A stainless steel ball  50 , spacer  52 , spring  54  and a pair of set screws  56  function to hold member  42  in position in piston head  20 . The tension on spring  54  is controlled and maintained by adjustment of the pair of set screws. It is important that the tension be maintained within a suitable range. If the tension is too loose, member  42  will be blown out of position. If the tension is too tight, member  42  will not be able to move in the piston head to release the air. Utilizing two set screws will allow for the necessary adjustment and maintenance thereof to insure optimum valve function. 
     Operation of the invention is best depicted in FIGS. 2A and 2B. As shown in FIG. 2A, valve  30  is opened to allow compressed air A to flow through opening  12   a  into contact with piston head  20 . Actuator  40  is nested in the piston head so that no air can flow therethrough. The air pressure will cause piston head  20  to move toward the distal end of body  14  causing spring  21  to compress (FIG. 2B) and allowing plunger  20   b  to pump fluid F from chamber  14   b  through discharge conduit  26 . When the piston head reaches the end of chamber  14   a , spring  48  will contact a wall in the chamber and causing the spring to compress and move member  42  to a position (FIG. 2B) whereby air A can escape from chamber  14   a  and exit the pump body. This will allow spring  21  to return the piston head to its original position while causing fluid F to be drawn into chamber  14   b . This cycle may be repeated at a rate determined by the adjustment of valve  30 . 
     The check valves in conduits  26  and  28  will alternately open and close on the pumping and suction cycle. FIG. 5 illustrates a preferred form of a discharge check valve to be used with the pump. Valve conduit member  60  is adapted to fit into an opening in the body of the pump. Member  60  includes a PTFE seat  62  which functions to seat a stainless steel ball valve  64 . Compression spring  66  biases ball  64  toward the seat. A second valve conduit member  68  is provided with a threaded nipple and is adapted to be threaded into member  60  for retaining spring  66  and ball  64  therein. A stainless steel seal  65  interposes member  60  and member  68 . Fluid being discharged from the pump will move ball  64  against the bias of spring  66  to allow fluid to flow through members  60  and  68 . During the suction cycle, retainer spring  66  prevents the ball from being sucked into the head on the upstroke. On the down stroke, fluid pressure seats the ball onto the PTFE seat. 
     FIG. 6 is illustrative of a preferred check valve arrangement utilized in suction conduit  28 . In the instant arrangement valve member  70  having PTFE seat  70   a  is provided with a threaded nipple and is adapted to be threaded into valve member  72  which is also provided with a PTFE seat. A first stainless steel valve ball  74  and a stainless steel seal  76  interposes members  70  and  72 . A second valve ball  74   a  and a retainer spring  78  (shown in phantom lines) are adapted to be disposed in member  72 . During the pumping cycle, fluid pressure in chamber  14   a  will push valve ball  74   a  into contact with the PTFE seat in member  72  while at the same time, ball  74  will be seated against PTFE seat  70   a , whereby a positive closure is attained. During the suction cycle, on the upstroke, balls  74  and  74   a  lift off the PTFE seats to allow fluid flow. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.