US3680986A

US3680986A - Pump with mechanical assist

Info

Publication number: US3680986A
Application number: US87864A
Authority: US
Inventors: Louis F Kutik; Erich W Gronemeyer
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-11-09
Filing date: 1970-11-09
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01

Abstract

A pump of the type which is used to dispense liquids and semiliquids from a container as a stream or spray is provided with an intake valve which normally closes the inlet passage of the pump with sufficient force to withstand relatively high pressures tending to force fluid into the pump from the container. Such forces may occur, for example, if the container is a plastic bottle which is squeezed. The actuator of the pump engages the intake valve when the actuator is depressed to assist in opening the intake valve, so that upon the return stroke of the actuator, fluid is sucked into the pump to be expelled therefrom when the actuator is again depressed.

Description

[451 Aug. 1, 1972 United States Patent Kutik et al.

[54] PUMP WITH MECHANICAL ASSIST Primary Examiner-Robert M. Walker Attorney-Settle and Oltman ABSTRACT derdale, Fla. 33316 Nov. 9, 1970 A pump of the type which is used to dispense liquids [22] Filed:

and semi-liquids from a container as a stream or spray 211 Appl. No.: 87,864

is provided with an intake valve which normally closes the inlet passage of the pump with sufficient force to [52] U.S. Cl....................................4l7/520, 222/384 withstand relatively high pressures tending to force [51] Int. 7/00, 367d 5/40 fluid into the pump from the container. Such forces [58] Field of Search......4l7/512, 513, 520, 569, 509,

may occur, for example, if the container is a plastic bottle which is squeezed. The actuator of the pump engages the intake valve when the actuator is [56] References Cited UNITED STATES PATENTS 417/520 X .417/520 X 417/520 X mm m epa mod OO CCD 678 666 999 1111 HUN 1 11 Claims, 12 Drawing Figures PATENTEDA B 1 I972 SHEET 1 OF 3 INVENTORS LOUIS F. KUTIK/ ERICH W. GRONEMEYER SETTLE & OLTMAN ATTORNEYS PATENTEUAUB H972 3.680.986

SHEET 2 BF 3 2% 2/6 v 20 3a 3O a4 32/ T64 g 54 3o 40 46 M o 2 42 1:34 I 56 34 SET 4T 66 E 38 6 FIG 7 T A! a P 1 i 22 28 38 T E I 21 52.

BY F168 INVENTORS LOUIS F. KUTIK ERICH W. GRONEMEYER SETTLE & OLTMAN ATTORNEYS PATENTEUAUB 1 I972 SHEET 3 BF 3 4 4 5 2 4 8 -H O 6 h is I m l r 1 7 r1. 8 I 4 4 8 6 2 ATTORNEYS 1 PUMP WITI-l MECHANICAL ASSIST RELATED DISCLOSURES This invention relates to a dispensing pump of the type described and claim in U.S. Pat. Nos. 3,507,586 and 3,527,551, both issued to Louis F. Kutik and Erich W. Gronemeyer, the present inventors.

BACKGROUND OFTHE INVENTION U.S. Pat. No. 3,507,586 describes and claims a pump which is made of relatively few parts that can be easily assembled. The parts can be made economically from plastic material by injection molding, and both the inlet valve and the outlet valve of the pump are included in a one-piece valve unit. The operation of the pump is reliable, partly due to the improved action of the outlet valve which is of a type forming a peripheral seal that can be opened and closed smoothly in response to movement of an actuator.

The features and advantages of that pump were continued in the pump which forms the subject matter of US. Pat. No. 3,527,551, and the inlet valve of the pump was improved by making it a self-biased yieldable seal which normally closes the inlet passage. With this improved inlet valve, fluid was less likely to leak from a container into the pump, and the actuator could be locked to hold the. intake valve closed to further prevent escape of fluid from the pump. I

It has been found, however, that if the pump is applied to a plastic bottle or other flexible container, it is v possible to squeeze the container repeatedly and in this manner force fluid from the container through the pump and out the outlet passage of the pump. This can only be done when the inlet valve is not locked closed,

as may well be the case when a diaphragm type of actuator is used on the pump. Similar back pressure tending toforce fluid out through the pump could occur as a result of vibrations or shocks encountered during shipment of flexible containers with pumps applied to them.

SUMMARY OF THE INVENTION The present invention overcomes the problems arising from back pressure created in the container by means of an inlet valve in the pump which normally closes the inlet passage of the pump with sufficient force to withstand relatively high pressures tending to force fluid from the container into the pump. Thus, the inlet valve may be biased against the inlet passage so strongly that suction created in the pump on the return stroke of the actuator would not, by itself, open the inlet valve. However, the actuator engages the inlet valve when the actuator is depressed and opens or assists in opening the inlet valve on the return stroke of the actuator so that fluid is sucked into the pump by the actuator.

As in the case of the patents referred to above, the outlet valve is a circular flap portion of a valve unit which yieldably contacts a circular surface of the housing of the pump. The inlet valve is made integrally with the outlet valve, and preferably includes a flexible ring connected to the exhaust valve and to a stem by radial arms in a manner such that the ring acts to bias the stem against the inlet passage of the pump but is yieldable to allow the stem to lift from the inlet passage on the return stroke of the actuator. The actuator preferably has another stem. One of the two stems is hollow and frictionally receives the other stem. Thus, when the actuator is depressed, the stems frictionally engage each other, and when the actuator returns, friction between the .two stem portions assists in opening the intake valveallowing fluid to enter the pump.

Accordingly, it is an object of the present invention to provide an improved inletvalve for a dispensing pump.

Another object of the invention is to providea pump with an inlet valve which remains closed even when considerable back pressure is built up inside the container to which the pump is attached, but which can be opened by depressing and releasing the actuator of the pump in a manner such that the actuator physically engages the inlet valve and assists in opening the inlet valve.

A further object of the invention is to provide an inlet valve which has a circle spring urging a stem forcibly against an inlet opening leading into a pump with sufficient force that the inlet valve will remain closed even though considerable back pressure is produced in the container to which the pump is afiixed. Other objects of this invention will appear from the following description and'appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

ON THE DRAWINGS FIG. 1 is a fragmentary elevational view of the top portion of a container showing a fluid dispensing pump FIG. 3 is a sectional view taken along line 3--3 of I FIG. 1 and looking in the direction of the arrows;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1 looking upward at the inside of the actuator of the pump;

FIG. 5 is a sectional view taken along line FIG. 3 looking in the direction of the arrows;

FIG. 6 is a fragmentary'sectional view taken along line 6--6 .of FIG. 3 looking in the direction of the arrows;

FIG. 7 is a sectional view similar to FIG. 3, but showing the actuator of the pump in a depressed condition;

FIG. 8 is another sectional view similar to FIG. 3, but showing the actuator of the pump as it is returning towards its initial position, with the actuator assisting in opening the inlet valve of the pump;

FIG. 9 is a sectional view of a valve unit included in the pump; I

FIG. 10 is a plan view of a pump which forms another embodiment of the invention, the top of the pump being broken away to reveal the valve unit;

FIG. 1 l is a sectional view taken along line 11-11 of FIG. 10 showing the interior of the second embodiment of the pump; and

FIG. 12 is a sectional view similar to FIG. 11, but showing the actuator of the pump in a depressed condition.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

DETAILED DESCRIPTION OF THE INVENTION The pump of FIGS. 1-9 inclusive includes a housing 22 and an actuator 24 assembled together to form a compartment in which a valve unit 26 is mounted. The housing 22 has a bottom wall 28 which includes a downwardly projecting wall portion 28. There are five upstanding

annular walls

30, 32, 34, 36 and 38. All of these walls are concentric.

The actuator 24 has a peripheral rim portion 40 which fits between and is squeezed by

walls

30 and 32 to anchor the actuator on the housing. The rim 40 is held by edge 31 which is swedged over a shoulder of rim 40. The valve unit 26 has a downwardly projecting cylindrical skirt 42 which is sealingly affixed between

walls

34 and 36. The valve unit 26 also has a stern portion 44 which projects downwardly from the center of a web portion 46 of the valve unit into the interior of the innermost annular wall 38. The lower end 48 of the stem 44 seats on an inlet opening 50 where the inlet passage 52 of the pump terminates. Thus, the valve unit, and particularly. the stem portion 44, closes the inlet opening 50. The web 46 and the stem 44 thus constitutes the intake valve portion of the valve unit 26.

The exhaust valve portion of the valve unit 26 is in the form of a circular, yieldable flap 54 which projects radially outwardly from the skirt 42 and'is made as one piece with the intake valve and the skirt 42. The entire valve unit is preferably molded from plastic material by injection molding. The flap 54 has a circular sealing edge 56 which is slightly larger in diameter than the annular surface 58 of wall 32 and fits inside that wall so that the flap 54 bends inwardly and is self-biased outwardly against the surface 58. Thus, the edge 56 forms a peripheral seal which is normally closed so that the exhaust valve is closed.

The flap 54 divides the compartment of the pump into an input chamber 60 and an output chamber 62. The inlet passage 52 leads into the input chamber 60 through the wall 38 and the web 46. A spout 64 has an outlet passage 66 which leads into the outlet chamber 62 and extends transversely of the wall surface 58.

The actuator 24 has a downwardly projecting stem portion 70, and one of the two

stem portions

44 and 70 is hollow; the stem portion 44 being hollow in the embodiment of FIGS. 1 through 9. Stem portion 70 is aligned with stem portion 44 and has a narrowed down tip 72 which just enters the hollow stem portion 44 when actuator 24 is in its initial position as shown in FIG. 3. The hollow stem portion 44 has projections 74 on its inner surface which may be in the form of flats, and these projections 74 are engageable by the stem 70 with a sliding friction fit. Thus, when the actuator 24 is depressed in the manner shown in FIG. 7, the stem 70 frictionally engages and slides along the projections 74 tending to further force the hollow stem portion 44 downward against the inlet opening50 keeping the intake valve closed. Then, when the actuator 24 is released,'it returns toward its initial position in the manner shown in FIG. 8, and it may be seen that the sliding friction between the stem and the projections 74 acts to lift the intake valve, and particularly the stem portion 44, off the intake opening 50 so as to open the intake valve. The actuator 24 thus sucks fluid from the container 21 through the inlet passage 52, the inlet opening 50, the wall 38 and past the web portion 46 into the input chamber 60. When the .actuator 24 is again depressed, the actuator forces fluid from the input chamber 60 against the exhaust valve flap 54 causing that flap to bend inwardly away from the surface 58, so that fluid flows past the sealing edge 56 into the output chamber 62 and out through the outlet passage 66. The fluid may be expelled as a liquid stream or as a spray. Where a spray is desired, a cap is normally provided on the spout 64 in the manner described in US. Pat. No. 3,527,551.

The web 46 as shown in FIG. 2 includes'a flexible plastic ring 78 which is connected by arms 80 to the hollow stem portion 44, and which is connected by other arms 82 to the exhaust valve flap 56. When the skirt 42 of the valve unit 26 is fully inserted into the space between

walls

34 and 36, the stem portion 44 pushes upwardly on the web 46 and causes the ring 78 to flex and become distorted slightly so that it acts to bias the stem 44 against the intake opening 50. The ring 78 thus acts as a circle spring which firm urges the stem 44 against opening 50 so as to close the intake valve with sufficient force to resist relatively high back pressure which may occur in the container 21. As previously pointed out, the container 21 may be a rigid material such as glass or it may be a flexible material such as plastic. In cases where the container 21 is plastic, it is easy for the plastic to become distorted as by squeezing, and if the intake valve were not firmly closed, it would be possible to pump fluid out through the pump as a result of the squeezing action. However, the spring action of the web portion 46 of the intake valve closes the intake valve firmly enough to prevent this back pumping of fluid.

Even though the intake valve is normally firmly closed, the actuator 24 with its stem 70 acts upon depression of the actuator to engage the intake valve and assist in opening the intake valve so that the actuator can suck fluid into the compartment. The stem 70 thus constitutes a lifting means which frictionally engages the hollow stem 44, and on the return stroke of the actuator, tends to lift the hollow stem 44 off the intake opening 50 and thus open the inlet valve.

Either the actuator or the exhaust valve flap 54 may be provided with nibs or projections 84 which cause the actuator to engage the exhaust valve flap 54 when the actuator is fully depressed and thus open the exhaust valve very slightly in the manner shown in FIG. 7. This allows air to enter the input chamber 70 through the outlet passage 66 so as to reduce the vacuum in the input chamber, and thus allow the actuator 24 to return easily to its initial position. This incoming air also mixes withfluid being sucked into the input chamber 60 on the return stroke of the actuator, and where this fluid is relatively viscous, the air mixed with it can produce bubbles which reduces the viscosity of the fluid enough to help it flow. Another advantage of the projections 84 is that they are engaged by the actuator when it is fully depressed to assure that the sealing edge 56 is fully seated within the annular surface 58.

Another projection 86 in the form of a ring engages the valve unit 26 immediately adjacent the skirt 42 when the actuator is fully depressed as shown in FIG. 7, and the ring 86 thus pushes down on the valve unit 26 to assure that the skirt 42 is fully seated down within the space between

walls

34 and 36. The skirt 42 prevents any fluid from leaking directly from inlet passage 52 to outlet passage 66 bypassing the input chamber 60.

The embodiment of FIGS. -12 inclusive is very nearly the same as the embodiment of FIGS. l-9, so the same reference numerals are used for like parts. As shown in FIG. 10, one difference is that the ring 78' of the web 46' is connected to the exhaust valve by only two arms 82' and is connected to the stem portion 44 by only two arms 80'. Another difference is that the stem portion 44 of the intake valve includes a cup 45 and an upwardly projecting stem 47. The stem portion 70' of the actuator is hollow and has projections 71 on its inner surface which frictionally engage the stem 47 when the actuator is depressed and tend to lift the stem portion 44' when the actuator returns towards its initial position. Wall 38 is omitted. in all other respects, the embodiment of FIGS. 10-12 is identical to the embodiment of FIGS. 1-9, so that description will not be repeated.

The invention thus provides an improved intake valve for a pump with a mechanical assist for helping to open the intake valve. The intake valve resists back pressures built up within the container towhich the pump is attached so that fluid does not leak into the pump when it is not wanted. The lifting means of the actuator overcomes this biased condition of the input valve to allow fluid to be sucked into the pump when the actuator is depressed and released.

Having thus described our invention, we claim:

1. A pump for expelling fluid from a container, said pump including a compartment having an inlet passage and an outlet passage communicating therewith, a normally closed intake valve for said inlet passage, and a normally closed exhaust valve for said outlet passage, said compartment including an actuator having lifting means frictionally engageable with said intake valve upon depressing said actuator in order to hold said intake valve closed, said actuator being returnable with friction between said lifing means and said intake valve assisting in opening said intake valve so that said actuator sucks fluid through said inlet passage into said compartment, said lifting means comprising first and second stem portions respectively affixed to said intake valve and said actuator, one of said stem portions receiving the other stem portion frictionally to lift said intake valve upon the return stroke of said actuator by frictional engagement of said stem portions with each other, said intake valve including flexible ring means connected to said exhaust valve and to said first stem portion by arm means in a manner such that said ring means acts to bias said first stem portion against said inlet passage to close the same in the rest condition of said pump and yields when said intake valve opens.

2. A pump for expelling fluid from a container, said pump including a compartment having an inlet passage and an outlet passage communicating therewith, a nor mally closed intake valve for said inlet passage, a normally closed exhaust valve for said outlet passage, and an actuator depressible into said compartment to expel fluid past said exhaust valve out said outlet passage and returnable to suck fluid through said inlet passage past said inlet valve into said compartment, said exhaust valve and said inlet valve being made integrally as one piece, and said inlet valve including a web and a stem portion, said web having a flexible ring connected to said exhaust valve and to said stem portion by radial arms in a manner such that said ring acts to bias said stem portion against said inlet passage to close the same but is yieldable to allow said stem portion to lift from said inlet passage to open the same on the return stroke of said actuator.

3. In a pump for expelling fluid from a container, the pump including a compartment having an inlet passage and an outlet passage both communicating therewith, an intake valve for said inlet passage, an exhaust valve for said outlet passage, the improvement wherein said compartment has an opening at which said inlet passage terminates, said intake valve comprises a web of plastic material made as one piece with said exhaust valve, said web having a first stem portion thereon and normally closing said intake opening, and said compartment including an actuator having a second stem portion engageable with said first stern portion, one of said stem portions being hollow and capable of receiving the other stem portion with a sliding friction fit, said actuator being depressible into said compartment to expel fluid past said exhaust valve out of said outlet passage and also to frictionally engage said first and second stem portions with each other, and said actuator being returnable with friction between said stem portions assisting in lifting said web to open said intake opening so that said actuator sucks fluid through said inlet passage into said compartment.

4. In a pump for expelling fluid from a container, the pump including a compartment having an inlet passage and an outlet passage both communicating therewith, an intake valve for said inlet passage, an exhaust valve for said outlet passage, the compartment having an annular upstanding surface relative to which said outlet passage extends transversely, and the exhaust valve comprising a resiliently flexible flap having a circular sealing edge portion engaging said annular surface, said flap dividing the interior of said compartment into an input chamber with which said inlet passage communicates and an output chamber with which said outlet passage communicates, the improvement wherein said compartment has an opening at which said inlet passage terminates, said intake valve comprises a partially open web of plastic material made as one piece with said exhaust valve flap and located centrally of said flap, said web having a first portion thereon and normally closing said intake opening, and said compartment including an actuator having a second portion engageable with said first portion, one of said first and second portions being capable of frictionally receiving the other portion, said actuator being depressible into said input chamber to expel fluid past said sealing edge through said output chamber and out of said outlet passage and also to frictionally engage said first and second portions with each other, and said actuator being returnable with friction between said first and second portions assisting in lifting said web to open said intake opening so that said actuator sucks fluid through said inlet passage past said web into said input chamber.

5. In a pump for expelling fluid from a container, the pump including a compartment having an inlet passage and an outlet passage both communicating therewith, an intake valve for said inlet passage, an exhaust valve for said outlet passage, the compartment having an annular upstanding surface relative to which said outlet passage extends transversely, and the exhaust valve comprising a resiliently flexible flap having a circular sealing edge portion engaging said annular surface and slightly larger in diameter than said annular surface so thatsaid flap bends inwardly slightly and is self biased outwardly against said annular surface to form a peripheral seal, said flap dividing the interior of said compartment into an input chamber with which said inlet passage communicates and an output chamber with which said outlet passage communicates, the improvement wherein said compartment has an opening at which said inlet passage terminates, said intake valve comprises a web of plastic material made as one piece with said exhaust valve flap and located centrally of said flap, said web having a first stem portion thereon and normally closing said intake opening, and said compartment including an actuator having a second stem portion engageable with said first stem portion, one of said stem portions being hollow and capable of receiving the other stem portion, said actuator being depressible into said input chamber to expel fluid past said sealing edge portion through said output chamber and out of said outlet passage and also to frictionally engage said first and second stern portions with each other, and said actuator being returnable with friction between said stem portions assisting in lifting said web to open said intake opening so that said actuator sucks fluid through said inlet passage past said web into said input chamber.

6. The combination as claimed in claim in which said web includes a ring connected to said flap by radial arms and connected to said first stem portion by further radial arms in a manner such that said ring acts to bias said first stem portion against said intake opening to close the same.

7. The combination as claimed in claim 5 in which one of said stem portions has a series of projections engaged frictionally by the other stem portion.

8. The combination as claimed in claim 7 in which said first stem portion is hollow and has said projections thereon.

9. The combination as claimed in claim 7 in which said second stem portion is hollow and has said projections thereon.

10. The combination as claimed in claim 5 in which said actuator is engageable, upon depression thereof, with said flap to open said peripheral seal and thus reduce vacuum in said input chamber sufficiently to allow said actuator to return to its initial position and to admit air into said input chamber to mix with other fluid therein. 11. A pump for use in expelling liquids and semiliquids from a container as a stream or spray, said pump including a compartment having an inlet passage and an outlet passage communicating therewith, a normally closed exhaust valve for said outlet passage, an intake valve normally closing said inlet passage with sufficient force to withstand relatively high pressures tending to force fluid into the pump from the container, said compartment including actuator means engageable with said intake valve upon depressing said actuator means, said actuator means acting on said intake valve by physical engagement therewith when so depressed to assist in opening said intake valve so that said actuator means sucks fluid through said inlet passage into said compartment on the return stroke of said actuator means, said intake valve and said actuator means respectively having first and second engaging portions engageable frictionally with each other upon the return stroke of said actuator means to lift said intake valve, said engaging portions disengaging during a terminal portion of the return stroke of said actuator means, said intake valve including flexible resilient means connected to said exhaust valve and to said first engaging portion in a manner such-that said flexible resilient means acts to bias said first engaging portion toward said inlet passage to close the same in the rest condition of said pump and yields when said intake valve opens.

Claims

2. A pump for expelling fluid from a container, said pump including a compartment having an inlet passage and an outlet passage communicating therewith, a normally closed intake valve for said inlet passage, a normally closed exhaust valve for said outlet passage, and an actuator depressible into said compartment to expel fluid past said exhaust valve out said outlet passage and returnable to suck fluid through said inlet passage past said inlet valve into said compartment, said exhaust valve and said inlet valve being made integrally as one piece, and said inlet valve including a web and a stem portion, said web having a flexible ring connected to said exhaust valve and to said stem portion by radial arms in a manner such that said ring acts to bias said stem portion against said inlet passage to close the same but is yieldable to allow said stem portion to lift from said inlet passage to open the same on the return stroke of said actuator.

3. In a pump for expelling fluid from a container, the pump including a compartment having an inlet passage and an outlet passage both communicating therewith, an intake valve for said inlet passage, an exhaust valve for said outlet passage, the improvement wherein said compartment has an opening at which said inlet passage terminates, said intake valve comprises a web of plastic material made as one piece with said exhaust valve, said web having a first stem portion thereon and normally closing said intake opening, and said compartment including an actuator having a second stem portion engageable with said first stem portion, one of said stem portions being hollow and capable of receiving the other stem portion with a sliding friction fit, said actuator being depressible into said compartment to expel fluid past said exhaust valve out of said outlet passage and also to frictionally engage said first and second stem portions with each other, and said actuator being returnable with friction between said stem portions assisting in lifting said web to open said intake opening so that said actuator sucks fluid through said inlet passage into said compartment.

5. In a pump for expelling fluid from a container, the pump including a compartment having an inlet passage and an outlet passage both communicating therewith, an intake valve for said inlet passage, an exhaust valve for said outlet passage, the compartment having an annular upstanding surface relative to which said outlet passage extends transversely, and the exhaust valve comprising a resiliently flexible flap having a circular sealing edge portion engaging said annular surface and slightly larger in diameter than said annular surface so that said flap bends inwardly slightly and is self biased outwardly against said annular surface to form a peripheral seal, said flap dividing the interior of said compartment into an input chamber with which said inlet passage communicates and an output chamber with which said outlet passage communicates, the improvement wherein said compartment has an opening at which said inlet passage terminates, said intake valve comprises a web of plastic material made as one piece with said exhaust valve flap and located centrally of said flap, said web having a first stem portion thereon and normally closing said intake opening, and said compartment including an actuator having a second stem portion engageable with said first stem portion, one of said stem portions being hollow and capable of receiving the other stem portion, said actuator being depressible into said input chamber to expel fluid past said sealing edge portion through said output chamber and out of said outlet passage and also to frictionally engage said first and second stem portions with each other, and said actuator being returnable with friction between said stem portions assisting in lifting said web to open said intake opening so that said actuator sucks fluid through said inlet passage past said web into said input chamber.

6. The combination as claimed in claim 5 in which said web includes a ring connected to said flap by radial arms and connected to said first stem portion by further radial arms in a manner such that said ring acts to bias said first stem portion against said intake opening to close the same.

10. The combination as claimed in claim 5 in which said actuator is Engageable, upon depression thereof, with said flap to open said peripheral seal and thus reduce vacuum in said input chamber sufficiently to allow said actuator to return to its initial position and to admit air into said input chamber to mix with other fluid therein.

11. A pump for use in expelling liquids and semi-liquids from a container as a stream or spray, said pump including a compartment having an inlet passage and an outlet passage communicating therewith, a normally closed exhaust valve for said outlet passage, an intake valve normally closing said inlet passage with sufficient force to withstand relatively high pressures tending to force fluid into the pump from the container, said compartment including actuator means engageable with said intake valve upon depressing said actuator means, said actuator means acting on said intake valve by physical engagement therewith when so depressed to assist in opening said intake valve so that said actuator means sucks fluid through said inlet passage into said compartment on the return stroke of said actuator means, said intake valve and said actuator means respectively having first and second engaging portions engageable frictionally with each other upon the return stroke of said actuator means to lift said intake valve, said engaging portions disengaging during a terminal portion of the return stroke of said actuator means, said intake valve including flexible resilient means connected to said exhaust valve and to said first engaging portion in a manner such that said flexible resilient means acts to bias said first engaging portion toward said inlet passage to close the same in the rest condition of said pump and yields when said intake valve opens.