GB2179406A

GB2179406A - Dispensing pump for a fluid contained in a container

Info

Publication number: GB2179406A
Application number: GB08615523A
Authority: GB
Inventors: Francisco Rodriguez Gazulla
Original assignee: Monturas y Fornituras SA
Current assignee: Meadwestvaco Calmar SL
Priority date: 1985-07-24
Filing date: 1986-06-25
Publication date: 1987-03-04
Also published as: ES288332Y; ES288332U; FR2585414B1; FR2585414A1; DE3624657A1; GB2179406B; GB8615523D0

Abstract

A dispensing pump for a fluid contained in a container comprises a body (2) defining a pumping chamber (4), communication of which with the container is controlled by a first valve (6). A piston (14) is movable in the chamber between two extreme positions and is urged to the position providing for the maximum pumping chamber volume by a first spring (24). A second valve (28) controls the communication of the pumping chamber with the outside and spring means (68) urge the valve to the closed position. The pump is provided with an opening member (46) for opening the second valve (28) when the piston is in the pumping chamber minimum volume position. In an alternative embodiment (not shown), the opening member depends from the valve (28) and engages the ball (10) of the first valve (6) to lift round valve member (28) off its seat. <IMAGE>

Description

SPECIFICATION Dispensing pump for a fluid contained in a container BACKGROUND OF THE INVENTION The invention relates to a dispensing pump for a fluid contained in a container. Pumps of this type comprise a body defining a pumping chamber; a first valve for controlling the communication between the container and the pumping chamber; a piston adapted for movement in the interior of the pumping chamber between a first position determining a maximum volume of the pumping chamber and a second position determining a minimum volume of said chamber; a first means such as a spring urging said piston to said first position; a second valve for controlling the communication of the pumping chamber with the outside; and second means such as a spring urging said second valve to the closed position thereof.

DESCRIPTION OF THE PRIOR ART The pumps of the above type may have an important drawback for priming the pump when the pumping chamber is full of air only. Under these circumstances, movement of the pump would cause compression of the air in the chamber and on the piston recoiling, instead of sucking fluid from the container, it would only the air to return to the normal pressure thereof.

Several systems are known to overcome this situation. In one of them, the main piston or a secondary piston, on moving downwards, engages a larger diameter O-ring or a protuberance ("wart") on the inner surface of the pumping chamber, which causes a levelling of the pressures in the container and the chamber, since the air may flow between the piston and the pumping chamber wall. This system is onerous, since the decompression is made independent from the sealing therewith and generally the means used for sealing are usually expensive. In a system of this type, the decompression occurs because part of the piston is deformable and allows the air to flow by on engagement with the wart, while in general the sealing system is rigid to obtain a good seal.

In another of the aforesaid systems, when the piston reaches the end of its stroke, the pumping chamber volume is so small that the air therein reaches such a pressure as to be able to open the second valve, because the force thereof, when applied to the stopper of the second valve is greater than that of the spring means used to urge the said second valve towards the closed position thereof.

Nevertheless, in such systems, the foree of the spring means used to seal the second valve may not be very high, since otherwise it would be practically impossible to open it by the mere compression of the air in the pumping chamber, since no matter how well designed the latter is, there are always dead chamber spaces allowing air to accumulate therein. This limitation of the sealing foree of the spring means has a negative effect on the fluidtightness.

Finally, there is a third known system in which the second valve is mechanically opened when the piston starts moving. A good degree of fluidtightness may be obtained with this system, but once the pump has been primed, it may not work as a precompression system, since from the outset the pumping chamber has been communicated with the outside.

SUMMARY OF THE INVENTION The object of the invention is to provide a pump of the aforesaid type, wherein the above priming drawback is also overcome, although by extremely simple and cheap means and wherein there are overeome also the said drawbacks of the commonly known systems.

For such purpose the pump of the invention is characterised in that it is provided with an opening member which in said second position of said piston opens said second valve overcoming said spring means and establishing communication between the pumping chamber and the outside.

When said piston is integral with a tubular stem, aligned with the piston and extending away from said pumping chamber, there being a transverse wall separating said tubular shaft from said pumping chamber, the invention is also characterised in that said second valve comprises a valve seat and a stopper, said valve seat being formed in said wall; said stopper being adapted for movement in the interior of said tubular stem; and said spring means being housed in the interior of said tubular stem.

Preferably according to the invention, said spring means are made of plastics material and are integral with the stopper and with a crown member for holding said part in said tubular stem.

In a further development of the invention, said crown member is provided on the outside thereof with a generally transverse surface forming an annular shoulder having an edge of diameter slightly larger than the inside diameter of said tubular stem, there being at one side of the shoulder a cylindrical portion of the crown member, having diameter generally the same as the inside diameter of the tubular stem, while on the other side of the crown member shoulder there is a portion of the crown member having a frustoconical outer surface tapering from the edge of the shoulder, said shoulder edge being pressed into said tubular stem and said spring means are constituted by at least two strips of generally helical configuration extending be tween the frustoconical portion of the crown member and the stopper.

Alternatively according to the invention, said opening member is integral with said stopper, forming an extension thereof, or said opening member is attached to said body.

BRIEF DESCRIPTION OF THE DRAWINGS To facilitate an understanding of the foregoing, reference is made hereinafter to the sheets of drawings accompanying this specification which drawings, in view of their explanatory nature, are to be understood as devoid of any limitating effect on the scope of protection being applied for. In the drawings: Figure 1 is an axial section view of a fluid dispensing pump according to the invention, provided with means for coupling to the container, as well as operating means comprising in turn a passage to the outside, the pump piston being in the maximum chamber volume position and the opening member being attached to the pump body.

Figure 2 is a sectional view similar to the above, the pump piston being in the minimum pumping chamber volume position, part of the outline of the container being shown in phantom lines.

Figure 3 is a sectional view on the line Ill-Ill of Figure 1.

Figure 4 is a sectional view similar to that of Figure 1, of a second embodiment wherein the operating means comprise a spray device and the opening member is an extension of the second valve stopper.

Figure 5 is a sectional view similar to that of Figure 4, with the pump piston being in the minimum pumping chamber volume position.

Figure 6 is a sectional view on a larger scale of one embodiment of the second valve.

DESCRIPTION OF THE PREFERRED EMBODI MENTS The pump of the invention comprises a body 2 defining a pumping chamber 4, which is provided at the lower end thereof with a first valve 6 formed by a valve seat 8 formed in the body 2 itself and a ball 10; said valve 6 is adapted to control the communication between the pumping chamber 4 and the container 12, shown in part in phantom lines in Figure 2. Below the valve 6 there is provided a passage 11 (shown only in part) which either alone or coupled to a dip tube-not shown-allows a communication between the pumping chamber and the bottom of the container 12.

A piston 14 is adapted for movement in the interior of the pumping chamber 4. The piston is provided with a portion 16 adapted to the inner surface of the body 2 and an annular groove 22 adapted to receive one end of a first spring 24, the other end of which engages the transverse portion or bottom 26 of the body 2.

In said embodiment, the second valve 28 comprises a valve seat 32 formed in a wall 34 of the piston 14, which wall is interposed between the pumping chamber 4 and a tubular stem 30 attached to the piston and which extends away from the pumping chamber. The valve 28 is provided with a stopper 36 which is adapted for movement in the interior of the tubular stem 30 and furthermore there are spring means 68 (to be described hereinafter) urging the stopper 36 to engage the valve seat 32, i.e. holding the valve 28 closed.

The piston 14 movement is limited in one direction by compression of the spring 24 and in the opposite direction by the penetration of a safety ring 38 in an upper annular groove 20. Said ring 38 is provided with means to receive therein a screw cap 40, in turn allowing the pump to be fitted to the container 12.

By way of a press fit, the upper end of the stem 30 is connected to an operating means for the piston, to facilitate the application of a manual force in the axial direction of the pump. Said operating means do not form part of the present invention and may comprise either a nozzle 42 specially adapted to dispense fluids (Figures 1 and 2) or a spray means 44 (Figures 4 and 5) adapted for liquids. Obviously, as far as the operating means is concerned, the pump of the invention is limited in no way.

According to the invention, the pump is provided with an opening member which is the minimum pumping chamber volume position of the piston 14 engages said second valve 28, opening it against the bias of the spring means and establishing communication, therefore, between the pumping chamber 4 and the outside.

According to one embodiment, the opening member 46 (Figures 1 to 3) is attached to the body 2 by means of legs 48 attached to a washer 50 engaging the transverse portion 26 of the body 2. Between the legs 48, the member 46 is provided with a longitudinal tab 52 preventing the ball 10 from moving too far away from the valve seat 8.

In a further embodiment, the opening member 54 is integral with the stopper 36, forming an extension thereof.

Preferably, the spring means for the second valve 28 are made from plastics material and are integral with the stopper 36 and with a crown member holding the whole in the tubular stem 30.

Preferably the crown member 56 is provided on the outside thereof (Figure 6) with a generally transverse surface 58 providing an annular shoulder 60, the edge 62 of which has a dismeter slightly larger than the inside diameter of the tubular stem 30.

On the downstream side of the shoulder 60, there is provided a cylindrical portion 64 of the crown member, while the upstream side of the shoulder is provided with an inwardly tapering frustoconical surface 66. Therefore, the crown member may be inserted in the downstream end of the stem until the desired position is reached, it being practically impossible for the crown member to move backwards since the edge 62 of the shoulder bites into the inner surface of the tubular stem 30.

In turn the spring means preferably are formed by two or more strips 68 having a generally helical configuration and extending between the crown member 56 and the stopper 36.

In view of the foregoing, it is easy to understand the operation of the pump. The pump is appropriately fitted to the container by means of the screw cap 40, whereby the pumping chamber 4 is filled only by air.

Thereafter, the operating means 42, 44 are depressed in the longitudinal direction of the pump. This closes the first valve 6 and the air contained in the pumping chamber 4 is compressed. When the piston 14 reaches the minimum pumping chamber volume, the opening member 46, 54 causes the stopper 36 to back up, thereby opening the second valve 28 and establishing communication between the pumping chamber 4 and the outside, whereby the pressure of the air in the pumping chamber is balanced with that of the outside air.

When the depression on the operating means 42, 44 is removed, the force of spring 24 causes the piston 14 to rise, whereby a depression is created in the pumping chamber 4; thus the valve 6 opens and the fluid contained in the container flows into the pumping chamber through the passage 11.

When the pumping chamber is compressed again by a new lowering of the piston 14, the hydraulic pressure of the fluid contained in the chamber is capable of opening the second valve 28, whereby said fluid attains the outside through the tubular stem.

Claims

1. A dispensing pump for fluid contained in a container comprising: a body defining a pumping chamber; a first valve for controlling the communication between the container and the pumping chamber; a piston adapted for movement in the interior of the pumping chamber between a first position determining a maximum volume of the pumping chamber and a second position determining a minimum volume of said chamber; first means urging said piston to said first position; a second valve for controlling the communication of the pumping chamber with the outside; and second means urging said second valve to the closed position thereof, wherein said pump includes an opening member which in said second position of said piston opens said second valve overcoming said second means and establishing communication between the pumping chamber and the outside.

2. A pump as claimed in claim 1 wherein said first means and said second means are springs.

3. A pump as claimed in claim 2, in which said piston is attached to a tubular stem extending from said pumping chamber, there being a transverse wall separating said tubular stem from said pumping chamber, and wherein said second valve comprises a valve seat and a stopper, said valve' seat being formed in said wall; said stopper being adapted for movement in the' interior of said tubular stem; and said spring means being housed in the interior of said tubular stem.

4. A pump as claimed in claim 3, wherein said spring means are made from plastics material and are integral with said stopper and with a crown member for retaining said part in said tubular stem.

5. A pump as claimed in claim 4, wherein said crown member is provided on the outside thereof with a generally transverse surface providing an annular shoulder, the edge of which ahs a diameter slightly larger than the inside diameter of said tubular stem, there being on one side of the shoulder a cylindrical portion of the crown member, having a diameter generally the same as the inside diameter of the tubular stem, while on the other side of the crown member shoulder, there is a portion of the crown member having a frustoconical outer surface tapering from the edge of the shoulder, said shoulder edge being pressed into said tubular stem and wherein said spring means are at least two strips of generally helical configuration extending between the tapering portion of the crown member and the stopper.

6. A pump as claimed in claim 3, wherein said opening member is integral with stopper, forming an extension thereof.

7. A pump as claimed in claim 3, wherein said opening member is attached to said body.

8. A dispensing pump substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 or Figures 4 to 6 of the accompanying drawings.