Dispenser pump

Abstract: A dispenser pump has a base (3) incorporating an intake tube (4), an axially-upright cylindrical pump body (2) fixed on top of the base (3) by a screw-threaded engagement, and a cap plunger (1) having a piston (18) which sweeps the interior of the body (2). A discharge spout (7) opens from a discharge opening (9) adjacent the base (3). Both the outlet and inlet openings are valved by a one-piece valve body (10) in the form of a free-standing sleeve (102) resting on the base (3), with a peripheral lip (103) forming the outlet valve at one end of the sleeve and a radially-inward projection (100,106) forming the inlet valve as a flexible flap. The body (2) and base (3) are separable to release the valve body (10) for easy cleaning.

Description: This invention concerns dispenser pumps, more particularly pumps in which pumpable material is drawn from a supply into a pump chamber through a valved inlet and discharged from the pump chamber through a valved outlet, by the action of a reciprocable plunger - usually hand-operated - which alters the volume of the pump chamber. The reciprocable plunger may have a piston to sweep out a cylinder, or may constitute a cylinder to be swept by a fixed piston, or it may deform a deformable wall of the pump chamber such as a foldable or elastomeric diaphragm. In one known type of pump, the inlet enters the pump chamber through a base thereof, and the outlet is also from the lower part of the pump chamber to provide clearance for the sweeping of the piston of an upwardly spring-biased cap plunger, with an outward seal against the pump chamber wall. Valving of the inlet and outlet conventionally involves at least one ball valve. These are well-proven but require complicated assembly of a large number of parts, and are difficult to disassemble and clean thoroughly. The difficulty in cleaning is particularly troublesome when there is a need for hygienic pumping e.g. of food materials such as sauces. US-A-3680986 (Kutik & Gronemeyer) describes a pump which uses a one-piece valve in the form of a sleeve having a peripheral lip which forms an outlet valve and a central, flexibly-attached piece which forms an inlet valve. Both valves flex at the same level, however, and the sleeve serves no function other than for positive location and positioning of the valve body in deep recesses of the pump body. These will be very difficult to clean. EP-A-154545 discloses a trigger sprayer with a cylindrical pump chamber having inlet openings at one end and an outlet opening from the side near that end. Inlet and outlet valving is provided by a single one-piece sleeve which is assembled by pushing it into the pump chamber from the open end. Flaps across the base of the sleeve form an inlet valve; a sharply turned-back collar around the other end of the sleeve bear against the cylindrical chamber wall to form an outlet valve. Our aim herein is to put forward a valving arrangement for a plunger pump which is consistent with simple assembly, disassembly and cleaning. According to the invention, we provide a dispenser pump comprising at a first end of the pump, a pump base having a valved inlet opening; a pump body fixed releasably to the pump base and having a surrounding wall which extends from the pump base to define a pump chamber, the surrounding wall having a shoulder directed towards the pump base and an outlet opening between the shoulder and the pump base; at a second end of the pump, a plunger mounted to the pump body to be reciprocable relative thereto to alter the volume of the pump chamber in a pumping action of the dispenser pump, and a valve sleeve having a locating foot located releasably on the pump base; a sleeve wall extending axially from the pump base to define an outlet chamber between the sleeve wall and the pump body surrounding wall between the shoulder and the pump base, and so separating the outlet chamber from an inlet space defined inside the sleeve downstream of the inlet, and a flexible valve lip whose periphery bears sealingly against the shoulder of the pump body wall in a direction away from the pump base, to form an outlet valve between the pump chamber and the outlet chamber; release of the pump body from the pump base enabling removal of the valve sleeve from the pump. Preferably the valve sleeve is a one-piece body, e.g. moulded from plastics material. Most preferably it also comprises integrally a movable element - a flap or lip - of the inlet valve. The inlet valve element preferably projects into the sleeve interior at or near its foot, so as to co-operate with an inlet opening at or near the floor of the pump chamber. Most preferably, the movable element of the outlet valve extends around the upper edge of the sleeve, and the outlet space may correspondingly extend around the wall formed by the sleeve. The outlet valve lip is desirably urged against the shoulder surface in the closed condition by its own resilient deformation. The inlet space inside the valve body is desirably unobstructed so as to allow that space to be swept by a piston part of the pump plunger. For this, it is preferred that the inlet opening and valve be at or adjacent the bottom of the valve body, rather than projecting up into it. The pump can be dismantled by separating a base part having the inlet from a pump body part having the plunger, so that the valve body can then be removed, e.g. for cleaning. Preferably the base part has a screw-threaded engagement with the body part. It is also preferred that the valve body has a part which is trapped between the assembled body part and base part, to hold it in position. This may be e.g. a skirt or flange at the foot of the valve body. The pump outlet may have a radially-extending spout projecting from the pump body. For ease of cleaning, this may be detachable from the body. The plunger and inlet are preferably aligned along an axis of the pump, and the valve body sleeve is also preferably aligned with that axis. The base part of the pump is usually adapted to fix removably to a container of pumpable material. This may be by e.g. a cap element through which the inlet passage extends. Venting of the pump may be, as conventional, through clearances extending down around the wall of the inlet passage. A useful venting/non-venting feature for a pump of this general type can be provided by providing a location for a removable seal e.g. a sealing ring, to be positioned to close off a venting clearance around the inlet passage wall. This is useful when the pump is used on a flexible material supply container which is intended to collapse as its contents are consumed. A pump embodying the above concepts is shown in axial cross section in the drawing. The pump shown is an axially-upright, hand-operated pump made essentially from plastics material. This embodiment is intended for pumping food products such as sauces, and the dose size is typically 10 to 100ml e.g. 30ml. The basic pump elements are a closure cap 51 for fixing to a container neck, a pump base or core 3 incorporating an intake tube 4 which extends down through the cap 51 and clamps it axially, an axially-upright cylindrical pump body 2 fixed on top of the base 3, a cap plunger 1 on top of the body 2, and a discharge spout 7 projecting radially from the pump body near the junction with the base 3. A free-standing valve body 10 is seated in the bottom of the pump chamber 8 formed by the body 2, in axial register with the outlet opening 9 which leads to the spout 7. Typically the cap plunger 1, body 2, core 3 and spout 7 might be of polypropylene. The cap plunger 1 is connected, by a central axial stem 16, to a piston 15 which operates in the pump chamber 8 and is biased upwardly by a return spring 11. An outwardly directed seal 17 of the piston wipes the inner cylindrical wall of the pump body. A nitrile rubber "O" ring seated in a groove gives a suitable seal. The piston 15 has a central nose 18 projecting axially below the seal 17. The top of the base element 3 forms a generally flat floor 34 at the bottom of the pump chamber 8, through which the inlet tube 4 opens centrally, essentially flush but with a slight annular peripheral projection 20 on which an inlet valve flap 100 (described later) seats. The valve body 10 sits on top of the base 3. It is of more flexible material than the pump body components e.g. low density polyethylene. Its primary elements are a support and location portion 101 which sits on top of the base 3, a sleeve wall 102, cylindrical in this embodiment, which extends axially above the base up to slightly above the top of the outlet opening 9, a valve lip 103 around the top edge of the sleeve wall 102 and which engages the inner surface of the pump body 2 above the outlet 9, and the inlet valve element 100 (already mentioned) which projects radially in to the centre of the sleeve 102 from its wall near its foot. In more detail, the support portion 101 comprises a radial outward flange from the foot of the wall 102, with a peripheral skirt 104 which fits around a top boss 31 of the base 3 and has an in-turned lip 105 engaging under the boss 31 so that the valve body 10 is retained axially on the base 3. The downward skirt 104 is also trapped radially between the boss 31 and the plain bore just above a threaded skirt 21 at the bottom of the wall of the pump body 2 so that, in the assembled pump, the valve body cannot escape. The sleeve portion 102 has a slightly thickened lower part for stability, and the circular inlet valve flap 100 is connected to this thickened portion by a flexible neck 106. In axial register with the sleeve 102, the pump body 2 has a slight radial enlargement corresponding to an annular outlet chamber 25 extending around the outside of the sleeve wall 102. The outwardly-flaring valve lip 103 of the valve body, made relatively thin for flexibility, is urged against a downwardly-facing shoulder 26 at the top of this radially-enlarged portion. The lip 103 thereby separates the outlet chamber 25 from the main pump chamber 8, but in operation can flex away from its engagement with the shoulder 26 to allow pressurised material to escape from the pump chamber 8 into the annular outlet chamber 25 and to the outlet 9. The cylindrical space defined by the inside of the sleeve 102 is unobstructed, and is substantially - i.e. most of its volume - swept out by the nose 18 of the plunger 15 on the downstroke. The long upwardly-angled discharge spout 7 is snap-fitted onto a projecting spigot 27 on the pump body at the outlet 9, so that it can easily be pulled off. The pump can easily be dismantled by unscrewing the base 3 from the body 2. The base 3 and attached valve body 10 can then be withdrawn from the body, untrapping the flexible skirt 104 of the valve body so that this can then easily be pulled off the boss 31 of the base 3. With the spout 7 pulled off the body 2, the pump has been reduced to a number of basic parts which are all of relatively open construction and are easy to clean. This is a considerable practical advantage when the pump is being used with food products. In normal applications with rigid containers, the container needs to be vented to compensate for dispensed material. In this embodiment, this is provided for by a small clearance 40 between an outer skirt 32 of the base 3 and the top of the internally-threaded closure cap 51, through a central hole 41 of the closure cap 51 and down through small clearances between the threads 5 which clamp the cap 51 to the base 3 (by a nut 42 encircling the lower part of the intake tube 4). So that the pump can also be used for collapsible containers, e.g. "bag-in-box" containers, the interface between the intake tube 4 and the nut 42 is provided with a housing groove 43 which can be fitted with a seal ring e.g. a nitrile rubber "O" ring 44, to prevent venting. A flexible dip tube 22 of conventional type is pushed into the intake tube 4 from below. It should be understood that the words "top", "bottom" and the like are used herein for clarity of description and should not be taken as limiting on the invention as regards the orientation of the pump in use, although the illustrated specific embodiment is conventially used upright. They can be taken broadly as referring to opposite, first and second ends of the pump.

Claims: A dispenser pump comprising at a first end of the pump, a pump base (3) having a valved inlet opening (4); a pump body (2) fixed releasably to the pump base (3) and having a surrounding wall which extends from the pump base (3) to define a pump chamber (8), the surrounding wall having a shoulder (26) directed towards the pump base (3) and an outlet opening (9) between the shoulder (26) and the pump base (3); at a second end of the pump, a plunger (1) mounted to the pump body (2) to be reciprocable relative thereto to alter the volume of the pump chamber (8) in a pumping action of the dispenser pump, and a valve sleeve (10) having a locating foot (101) located releasably on the pump base (3); a sleeve wall (102) extending axially from the pump base (3) to define an outlet chamber (25) between the sleeve wall (102) and the pump body surrounding wall between the shoulder (26) and the pump base (3), and so separating the outlet chamber (25) from an inlet space defined inside the sleeve (10) downstream of the inlet (4), and a flexible valve lip (103) whose periphery bears sealingly against the shoulder (26) of the pump body wall in a direction away from the pump base (3), to form an outlet valve between the pump chamber (8) and the outlet chamber (25); release of the pump body (2) from the pump base (3) enabling removal of the valve sleeve (10) from the pump. A dispenser pump according to claim 1 in which the flexible valve lip (103) is at the end of the sleeve wall (102). A dispenser pump according to claim 1 or claim 2 in which the outlet chamber (25) is annular. A dispenser pump according to any one of the preceding claims in which the pump base (3) and pump body (2) trap the locating foot (101) of the valve body (10) when fixed together. A dispenser pump according to any one of the preceding claims in which the locating foot (101) is a skirt or flange extending radially outwardly. A dispenser pump according to claim 5 in which the locating foot has a skirt (104) which fits around a top boss (31) of the base (3) and has an in-turned lip (105) engaging under the boss (31) to retain the valve sleeve (10) axially on the base (3). A dispenser pump according to any one of the preceding claims in which the pump body (2) has a screw-threaded engagement with the pump base (3). A dispenser pump according to any one of the preceding claims in which the surface of the pump base provides a generally flat floor (34) of the pump chamber (8). A dispenser pump according to any one of the preceding claims in which the plunger (1) carries a piston (15) which sweeps the pump chamber (8). A dispenser pump according to claim 9 in which in use a central nose (18) of the piston (15) sweeps the inlet space in the valve sleeve (10). A dispenser pump according to any one of the preceding claims in which the valve sleeve (10) comprises an inlet valve element (100) projecting over the inlet opening. A dispenser pump according to claim 11 in which the inlet valve element is a flap (100) projecting into the interior of the valve sleeve (10) at or near its foot (101). A dispenser pump according to any one of the preceding claims in which the valve sleeve (10) is a one-piece plastics moulding. A dispenser pump according to any one of the preceding claims, having a discharge spout (27,7) projecting from the outlet opening (9). A dispenser pump according to claim 14 in which the discharge spout is detachable from the pump body (2). A dispenser pump according to any one of the preceding claims in which the pump base (3) has a cap element (51) for fixing removably to a container of pumpable material.

Inventors: LAW BRIAN ROBERT, LAW, BRIAN ROBERT
Applicants: ENGLISH GLASS CO LTD, THE ENGLISH GLASS COMPANY LIMITED
Application year: 1993
Main classification: B65D47
IPC codes: B65D47, B05B11