Direct Volume-Controlling Device (DVCD) for Reciprocating Positive-Displacement Pumps
A volume control device having a housing with an inlet passage, an outlet passage, and an internal chamber communicating with the inlet and outlet passages. An accumulator is movably positioned within the internal chamber and substantially conforms with walls of the internal chamber, the accumulator including an internal passage allowing fluid flow therethrough. An one-way valve is positioned in the internal passage of the accumulator where the valve is biased in a closed position and an adjustable seat is positioned within the housing internal chamber between the accumulator and the housing outlet passage. A positioning mechanism engages the housing and adjustable seat whereby the position of the adjustable seat within the housing internal chamber may be adjustably fixed.
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This application claims the benefit under 35 USC §119(e) to U.S. Ser. No. 61/639,524, filed Apr. 27, 2012, which is incorporated by reference herein in its entirety.
FIELD OF INVENTIONThe present invention relates to pumps and fluid injection systems.
BACKGROUNDPositive displacement pumps are used to deliver or “dose” a predictable, precise amount of fluid in a repeatable fashion. Commonly, positive displacement pumps use the reciprocating motion of a solid object such as a plunger, piston, or diaphragm to withdraw fluid from a continuous source during a suction stroke, then to displace the withdrawn fluid during a discharge stroke. In such reciprocating positive displacement pumps, it is typical to control the flow of fluid such that the withdrawn portion of fluid does not return to its source during the discharge cycle, but is prevented from doing so by a suction check valve that allows flow in only one direction, towards the pump. It is also typical that a discharge check valve be present to direct flow away from the pump and towards the intended recipient process and to prevent any fluid from returning to the pump from the recipient process during its operation.
Many embodiments of the present invention relate to controlling the flow rate or output of the fluid from the pump at the head portion of the pump assembly. In
Several other types of positive displacement pump heads utilize various means of alternately creating negative and then positive pressure to intake and then discharge fluid in a controlled manner. In each of these pump head designs, at least one suction check valve and at least one discharge check valve are employed. For example, a second, very common type of pump head, not illustrated in the drawings, is referred to as a “diaphragm” type pump head. This pump head utilizes hydraulic fluid pressure, generated by reciprocating motion of a plunger, to act on one side of a diaphragm or a sandwich of diaphragms. In this type of head design, the fluid being pumped is acted upon by the opposite side of the diaphragm or diaphragm assembly. Other types of pump heads utilize alternative means of controlling, actuating, and pumping fluid, e.g., a bellows type pump head. All such pump heads, and potentially many other conventional and future developed pump heads, may be used in conjunction with the present invention.
Many embodiments of the present invention relate to controlling the amount of fluid that is discharged during the discharge cycle of any reciprocating pump, regardless of type, including where the pump head utilizes a discharge check valve and mechanically changes the internal volume of a chamber via reciprocating motion.
The illustrated embodiment of adjustable seat 16 is best seen in
The illustrated embodiments of accumulator 10 further include a one-way valve 45 positioned within the accumulator's internal cavity 15. In these embodiments, the one-way valve is shown as being a poppet-type valve including poppet 46, pressure differential spring 47, spring retainer 48, and o-ring 49. The poppet 46 includes a series of side apertures 50 and while hidden from view, an open top section such that fluid entering the poppet side apertures may exit through the open top section. It can further be seen that spring 47 biases the end of poppet 46 having o-ring 49 against lower part of accumulator internal cavity 15. While the illustrated embodiments show a one-way valve formed of a poppet assembly, many different conventional or future developed one-way valves may be utilized, as nonlimiting examples, various regulators (e.g., back-pressure regulators), solenoid valves, or shuttle valves.
Although several structural components are positioned within housing internal chamber 5, there is nevertheless a fluid path around these components from inlet 3 to outlet 4. Once fluid pressure at inlet 3 causes one-way valve 45 to open and fluid is allowed to flow through accumulator 10, a fluid path exists through poppet 46, through adjustable seat circular base 64, around positioning mechanism 20, and through outlet 4.
OPERATION OF ILLUSTRATED EMBODIMENTSWhen employed in a positive displacement pump system, DVCD 1 may be connected to the pump head assembly by threads or other mechanical means located on the lower exterior of the housing 2 as suggested in
Through this description of
Those skilled in the art will readily understand that the dimensions of DVCD 1, including the diameter of the housing internal chamber 5 and accumulator 10, and the amount of travel allowed by varying the diameter of the cam member 22 at their largest and smallest dimensions, and possibly other parameters, will determine the maximum amount of fluid that will be subtractable from the output of a pump to which DVCD 1 is connected. It is preferred that DVCD 1 have a fully seated or closed position, in which the pump head has maximum output and efficiency, and then a variable amount of fluid which can be subtracted from the pump output by adjusting the accumulator position within DVCD 1.
Although certain specific embodiments of DVCD 1 have been described in detail in
A still further embodiment of the DVCD device is seen in
Shaft 215 is considered a “balanced shaft” in the sense that it has pressure bearing surfaces in multiple directions to neutralize pressure induced forces tending to bind its threaded surfaces.
The accumulator 210 is similar to that of other embodiments in that it includes a one-way valve formed of poppet 246 being biased against internal sidewalls of the accumulator by spring 247. Similarly, accumulator 210 have a wiper seal 255 and o-ring 240 engaging the tapered internal sidewalls at the lower section of housing 2B in order to form a seal when accumulator 210 is in its lower-most position.
Many other embodiments of the invention may be conceptualized by considering the functional components of the DVCD. For example, another embodiment is a DVCD in which a solid component moves in response to pressure exerted by fluid within a positive displacement pump head during its discharge cycle, and is subsequently replaced prior to that pump's replenishment cycle, subtracting thereby a portion of fluid that would otherwise have been discharged. This DVCD may have a solid component which is adjustable. A further DVCD embodiment substitutes for and acts as the discharge check valve of a positive displacement pump, in which a solid component moves as described immediately above, in concert with normal check valve components (e.g., a ball or poppet). In this embodiment, the solid component is also adjustable.
Those skilled in the art will recognize that the described embodiments of DVCD 1 directly control dosing volume without disturbing the mechanical motion of the driver. Instead, DVCD 1 directly varies dosing volume at the point of delivery by controlling the “apparent size” of the dosing chamber. DVCD 1 causes a precisely controlled portion of fluid that would normally be discharged during the discharge portion of the pumping cycle to be “borrowed” immediately before it is delivered, then “paid back” or returned to the dosing chamber immediately prior to the replenishment or suction portion of the dosing cycle. DVCD 1 allows a controllable solid component to move “in place” of a variable portion of the fluid that would have otherwise been discharged. This solid component moves a controlled distance in response to the hydraulic pressure from the discharge cycle, just prior to fluid discharge, and then resets itself in response to vacuum pressure just prior to the fluid replenishment or suction cycle, returning the displaced volume to the pump. It is entirely passive, merely reacting to the discharge and replenishment cycles, and it involves only one moving part in addition to what would exist in a non-controllable pump. Nevertheless, not all embodiments of DVCD 1 need have the above described functionalities and embodiments lacking such functionalities are also intended to come within the scope of the present invention.
Claims
1. A volume control device comprising:
- a. a housing having an inlet passage, an outlet passage, and an internal chamber communicating with the inlet and outlet passages;
- b. an accumulator movably positioned within the internal chamber and substantially conforming with walls of the internal chamber where the accumulator includes an internal passage allowing fluid flow therethrough;
- c. an one-way valve positioned in the internal passage of the accumulator where the valve is biased in a closed position;
- d. an adjustable seat positioned within the housing internal chamber between the accumulator and the housing outlet passage;
- e. a positioning mechanism engaging the housing and adjustable seat whereby the position of the adjustable seat within the housing internal chamber may be adjustably fixed.
2. The volume control device of claim 1, wherein the accumulator seals against a lower portion of the internal chamber and the internal passage of the accumulator is substantially aligned with the inlet passage of the housing.
3. The volume control device of claim 1, wherein the valve within the accumulator is a poppet type with a spring biasing it in the closed position.
4. The volume control device of claim 1, wherein a first position of the adjustable seat holds the accumulator against a lower portion of the housing internal chamber.
5. The volume control device of claim 4, wherein a second position of the adjustable seat allows the accumulator to traverse a first distance within the housing internal chamber.
6. The volume control device of claim 5, wherein a third position of the adjustable seat allows the accumulator to traverse a second, greater distance within the housing internal chamber.
7. The volume control device of claim 1, wherein the positioning mechanism comprises at least one cam member rotating within the housing internal chamber.
8. The volume control device of claim 6, wherein the accumulator is free to travel the first or second distance subject only to seal friction between the accumulator and wall of the housing internal chamber.
9. The volume control device of claim 7, wherein the positioning mechanism comprises two cam members engaging cam pins on the adjustable seat.
10. The volume control device of claim 1, further comprising a first seal positioned between the accumulator and a wall of the housing internal chamber and a second seal positioned between the adjustable seat and the wall of the housing internal chamber.
11. The volume control device of claim 1, wherein the positioning mechanism includes a control surface external to the housing.
12. The volume control device of claim 11, wherein the positioning mechanism includes a bolt member and the control surface is a gripping surface on one end of the bolt member.
13. The volume control device of claim 1, wherein the one way valve allows flow in the direction of the inlet passage toward the outlet passage.
14. The volume control device of claim 1, wherein the positioning mechanism comprises mating threaded surfaces on a portion of the wall of the housing internal chamber and on the adjustable seat.
15. The volume control device of claim 14, wherein the adjustable seat includes a threaded stem in-line with the inlet passage.
16. The volume control device of claim 1, wherein the accumulator has a larger first end and a smaller second end, and said smaller second end slides into an aperture in the adjustable seat.
17. The volume control device of claim 16, wherein the second end slides freely within the adjustable seat.
18. The volume control device of claim 1, wherein components positioned within the housing consist essentially of the accumulator, the adjustable seat, and the positioning mechanism.
19. The volume control device of claim 1, wherein the positioning mechanism comprises a means for altering the position of the adjustable seat within the housing in order to allow a different degree of travel within the housing by the accumulator.
20. A reciprocating pump system with adjustable volume control, the system comprising:
- a. a reciprocating pump having a fluid inlet allowing fluid to enter the pump during an intake cycle and a fluid outlet allowing fluid to exit the pump during a discharge cycle; and
- b. a volume control device in fluid communication with the pump outlet, the control device comprising: i. a housing having an inlet passage communicating with the pump outlet, an outlet passage, and an internal chamber communicating with the inlet and outlet passages; ii. an accumulator movably positioned within the internal chamber and have at least one surface substantially conforming with walls of the internal chamber where the accumulator includes an internal passage allowing fluid flow therethrough; iii. a valve positioned in the internal passage of the accumulator where the valve is biased in a closed position; iv. an adjustable seat positioned within the housing internal chamber; v. a positioning mechanism engaging the housing and adjustable seat whereby the position of the adjustable seat within the housing internal chamber may be adjustably fixed.
21. A volume control device comprising:
- a. a housing having an inlet passage, an outlet passage, and an internal chamber communicating with the inlet and outlet passages;
- b. a volume control means for controlling a volume of fluid within the internal chamber, the volume control means further including an internal passage allowing fluid flow therethrough;
- c. a flow direction control means for allowing one-way fluid flow, the flow direction control means being positioned in the internal passage of the volume control means and being biased in a closed position;
- d. a seating means for adjustably positioning the volume control means within the housing internal chamber, the seating means being between the volume control means and the housing outlet passage;
- e. a positioning means for adjustably fixing the position of the seating means within the housing internal chamber.
22. A volume control device comprising:
- a. an inlet passage and an outlet passage;
- b. an accumulator positioned in an accumulator chamber wherein the accumulator chamber is in fluid communication with the inlet passage;
- c. a positioning mechanism whereby the position of the accumulator in the accumulator chamber may be adjustably fixed;
- d. an one-way valve positioned in an one-way valve chamber wherein the one-way valve chamber is in fluid communication with the inlet passage; and
- e. wherein the one-way valve chamber is in fluid communication with the outlet passage and the one-way valve is biased in a position closing off the inlet passage from the outlet passage.
23. The volume control device of claim 22, wherein an accumulator passage provides a fluid connection between the outlet passage and the accumulator chamber.
24. The volume control device of claim 22, wherein an adjustable seat holds the accumulator against one end of the accumulator chamber.
25. The volume control device of claim 24, wherein a first position of the adjustable seat allows the accumulator to traverse a first distance within the accumulator chamber and second position of the adjustable seat allows the accumulator to traverse a second distance within the accumulator chamber.
26. The volume control device of claim 22, wherein the one-way valve is a poppet type with a spring biasing it in the closed position.
27. The volume control device of claim 22, further comprising a first seal positioned between the accumulator and a wall of the accumulator chamber.
28. The volume control device of claim 22, wherein the one-way valve allows flow in the direction of the inlet passage toward the outlet passage.
29. The volume control device of claim 24, wherein the positioning mechanism comprises mating threaded surfaces on a portion of the wall of the accumulator chamber and on the adjustable seat.
30. The volume control device of claim 22, wherein the accumulator chamber, the one-way valve chamber, the inlet passage, and the outlet passage are formed in a single unitary housing.
31. The volume control device of claim 22, wherein the accumulator chamber and the one-way valve chamber are formed in separate bodies and external conduits connect the inlet passage and the outlet passage to the accumulator chamber and the one-way valve chamber.
32. The volume control device of claim 1, wherein the accumulator substantially conforming with walls of the internal chamber includes a seal positioned between the walls and the accumulator.
Type: Application
Filed: Mar 14, 2013
Publication Date: Oct 31, 2013
Applicant: Checkpoint Fluidic Systems International, Ltd. (Mandeville, LA)
Inventors: Andrew C. Elliot (Covington, LA), Don Matherne, JR. (New Orleans, LA)
Application Number: 13/827,136