Piston pump dispenser for dispensing liquids

Abstract

 A piston pump dispenser for dispensing liquids such as soap, comprising a piston chamber (2) in fluid communication with an inlet (2a) and an outlet (1b). A piston (1) is arranged for a reciprocating movement between a depressed position and a retracted position within said piston chamber (2). A one-way valve assembly (3) arranged for preventing fluid flow from said outlet (1b) to said piston chamber (2). Characteristically, said inlet (2a) is arranged on the piston chamber (2) such that, when the piston (1) is displaced a certain distance from said retracted position towards said depressed position, the piston (1) closes the fluid communication between the inlet (2a) and the piston chamber (2), thus preventing liquid from flowing from the piston chamber (2) to the inlet (2a) when the volume of the piston chamber (2) is decreased.

Description

Field of the invention

[0001] The present invention concerns an arrangement for dispensing fluids. More particularly, the present invention concerns a piston pump dispenser for liquids, most particularly soap.

Prior Art

[0002] Different constructions of piston pumps for dispensing liquids, such as soap, from reservoirs is well known.

[0003] For example, publication US 2006/0231577 discloses a piston pump dispenser that comprises an inlet in fluid communication with a piston chamber, via a spring biased one-way ball valve so that fluid can only flow from the inlet to the piston chamber and not the other way around. The piston has a flow channel so that when the piston is depressed by a user, the volume of the piston chamber is reduced and the fluid within said chamber flows through the flow channel of the piston and further to an outlet. The piston is then retracted by a biasing spring, and the increase in the piston chamber's volume draws liquid from the inlet and fills the piston chamber with said liquid to be dispensed by a subsequent depress by a user. A further one-way valve located at the outlet prevents air from being drawn to the piston chamber from the outlet via the piston's flow channel during the retraction of the piston.

[0004] The construction described above is somewhat complex and requires several different components, such as two one-way valves. This results in, e.g., higher manufacturing costs and a complicated assembly procedure.

Objects of the Invention

[0005] The object of the present invention is to provide a piston pump dispenser that overcomes issues related to the prior art piston pump dispensers as described above. Particularly it is an object of the present invention to provide a piston pump dispenser having a more simple construction, and thus, facilitating the assembly thereof.

[0006] This object is achieved by providing an inlet on the piston chamber such that, when the piston is displaced a certain distance from a retracted position towards a depressed position, the piston closes the fluid connection between the inlet and the piston chamber. This prevents liquid from flowing from the piston chamber to the inlet when the volume of the piston chamber is decreased.

[0007] A less complex construction is achieved, as the need for a separate one-way valve between the piston chamber and the inlet or a reservoir is eliminated. Fewer component result in more reliable operation of a piston pump dispenser according to the present invention, in addition to reduced manufacturing costs. Additionally, as fewer components are required, assembly is made easier.

[0008] Further embodiments of the present invention and their advantages are described in the accompanying claims.

Brief Description of the Drawings

[0009] The present invention is described in more detail with reference to the accompanied drawing, in which:

Fig. 1 illustrates a piston pump dispenser according to an embodiment of the invention said piston pump being in a retracted position and attached to a reservoir

Fig. 2 illustrates an exploded view of the piston pump dispenser of Fig. 1

Detailed Description of the Invention

[0010] Fig. 1 illustrates a piston 1 inserted in a piston chamber 2, and having a conduit 1a for providing fluid communication between a piston chamber 2 and an outlet 1b. The piston comprises a one-way valve assembly 3 allowing fluid flow from the piston chamber 2 to the conduit 1a, but preventing fluid flow from the conduit 1a to the piston chamber 2. A biasing spring 4 is also arranged in the piston chamber 2 for biasing the piston 1 towards its retracted position, i.e. the position illustrated in Fig. 1

[0011] The piston further comprises a first recess 1c located at the end of the piston 1, on the piston chamber 2 side, and extending a distance in the longitudinal direction of the piston, i.e. the direction of the piston's movement. The first recess 1c is arranged to accommodate one end of the biasing spring 4, the other end being positioned against an opposing wall of the piston chamber 2. The first recess 1c also partly accommodates the one-way valve assembly, namely a valve seat 3c. In the embodiment of Fig. 1, the valve seat 3c is locked in position within the first recess 1c by the biasing spring 4 pushing said valve seat 3c against the piston 1.

[0012] In addition, the piston 1 comprises a second recess 1d extending from the bottom of the first recess 1c and extending in the longitudinal direction of the piston 1. The second recess is arranged to accommodate the rest of the one-way valve assembly 3, namely the valve member 3a and the valve spring 3b. The valve spring 3b and the valve member 3a are arranged in the second recess 1d so as to push the valve member 3a against the valve seat 3c.

[0013] The piston chamber 2 has an inlet 2a providing fluid communication with a reservoir 5. The inlet 2a is located along the travel path of the piston 1 in the piston chamber 2 so that, when moved a distance towards it's depressed position, the piston 1 blocks the inlet 2a, and thus, prevents fluid flow between the piston chamber 2 and the reservoir 5.

[0014] When the piston 1 is depressed, it moves towards the opposing end of the piston chamber, i.e. towards its depressed position. The inlet 2a is closed by the piston 1, and subsequently, the pressure in the piston chamber 2 increases. The increased pressure causes the one-way valve assembly 3 to open, i.e. the valve member 3a to be pushed away from the valve seat 3c, and permits fluid to flow from the piston chamber 2 to the outlet 1b via the first and second recesses 1c, 1d and the conduit 1a.

[0015] When the piston is no longer pressed, the biasing spring 4 pushes the piston 1 from its depressed position towards its retracted position. This causes the pressure in the piston chamber to decrease, and subsequently, the one-way valve assembly 3 to close, i.e. the valve member 3a to be pushed against valve seat 3c by the valve spring 3b. This ensures that fluid is not redrawn from the conduit 1a or outlet 1b back into the piston chamber 2. As the piston 1 has returned towards its retracted position, past the inlet 2a, the fluid connection between the piston chamber 2 and the reservoir 5 is opened again, allowing fluid to flow from the reservoir and fill the piston chamber 2.

[0016] Fig. 2 illustrates an exploded view of the piston pump dispenser of Fig. 1. As can be seen, this embodiment of the invention facilitates a simple assembly process because the piston pump dispenser's components can be inserted in the piston chamber 2 in the order of the component's final positions. Thus, no pre-assemblies are required.

[0017] A piston pump dispenser according to an embodiment of the invention comprises a piston chamber 2 having an inlet 2a for providing fluid communication between the piston chamber 2 and a reservoir 5. Preferably, the inlet 2a is positioned below a reservoir 5, suitably at the lowermost portion of said reservoir, so that the hydrostatic pressure of the fluid therein causes the fluid to flow from the reservoir 5 to the piston chamber 2. The piston pump dispenser further comprises an outlet 1b in fluid communication with the piston chamber 2, from which outlet 1b fluid can be dispensed to a user. A piston 1 is arranged within the piston chamber 2 such that at least a reciprocating motion in the longitudinal direction of the piston 1 is allowed between a retracted position and a depressed position of the piston 1, respectively. A one-way valve assembly 3 is provided between the outlet 1c and the piston chamber 2 for preventing fluid flow from the outlet 1b to the piston chamber 2. Particularly when the inlet 2a is placed beneath a reservoir 5, the one-way valve assembly 3 also prevents fluid from freely flowing from the reservoir 5 through the piston chamber 2 to the outlet 1b when the piston 1 is not depressed. In other words, the one-way valve 3 assembly also acts as a pressure relief valve enabling fluid flow from the piston chamber 2 to the outlet 1b only when the pressure in the piston chamber 2 has sufficiently increased due to the piston 1 being depressed.

[0018] As commonly known for piston pump -type dispensers, a movement of the piston 1 from the retracted position towards the depressed position reduces the volume of the piston chamber 2, thus causing fluid to flow from the piston chamber 2 to the outlet 1b. Correspondingly, a movement of the piston 1 from the depressed position towards the retracted position increases the volume of the piston chamber 2 and causes fluid to be drawn from the inlet 2a to the piston chamber 2.

[0019] In said embodiment according to the present invention, the inlet 2a is arranged on the piston chamber 2 in such a position that, when the piston 1 is displaced a certain distance from said retracted position towards said depressed position, the piston 1 closes the fluid communication between the inlet 2a and the piston chamber 2. This prevents liquid from flowing from the piston chamber 2 to the inlet, and correspondingly, ensures that fluid flows from the piston chamber 2 towards the outlet 1b when the volume of the piston chamber 2 is decreased

[0020] The inlet 2a is advantageously positioned in the piston chamber 2 in the vicinity of the piston 1 when it is in its retracted position. For example, the inlet 2a could be positioned such that the piston 1 starts to close the inlet 2a substantially immediately as it is moved towards the depressed position from the retracted position. This way, the inlet 2a becomes fully closed as the piston has been moved a distance corresponding to the dimension of the inlet 2a from the retracted position towards the depressed position. Preferably, the piston 1 closes the inlet 2a by blocking an opening that forms the outlet 2a on the inner wall of the piston chamber 2.

[0021] The piston 1 is preferably biased towards its retracted position. This arrangement facilitates the use of the dispenser, as a user only needs to actuate the piston in one direction, i.e. to-wards the depressed position in order to operate the dispenser. Correspondingly, the piston 1 may be actuated, e.g. by pushing the distal end of the piston. Naturally, any other actuating means, such as electronic ones, may be utilized. Suitably, a biasing spring 4 is arranged in the piston chamber 4 for biasing the piston 1 but other arrangements for locating the biasing spring 4 may be implemented. A conventional coil spring may be used, for example.

[0022] According to another embodiment of the invention, the piston 1 comprises a first recess 1c located on the piston chamber 2 side end of the piston 1, i.e. in the piston chamber 2. The first recess 1c extends a distance in the longitudinal direction of the piston 1, so as to accommodate at least a portion of the biasing spring 4.

[0023] In a further embodiment according to the present invention, the piston 1 is equipped with a conduit 1a. The conduit 1a extends within the piston so as to provide fluid communication between the piston chamber 2 and the outlet 1b. Preferably, the conduit 1a extends longitudinally within the piston 1. The one-way valve assembly 3 may be arranged in connection with the conduit 1a, suitably at the piston chamber 2 side end thereof.

[0024] According to yet another embodiment of the present invention, the piston 1 comprises a second recess 1d extending from the bottom of the first recess 1c in the longitudinal direction of the piston 1. In such an arrangement, the first recess 1c is preferably further arranged to accommodate a valve seat 3c of a one-way valve assembly 3. The valve seat 3c can, for example, be fixed in the first recess by the biasing spring 4, which pushes the valve seat 3c against the bottom of the first recess 1c. Further, the second recess 1d is preferably adapted to accommodate a valve member 3a and a valve spring 3b of a one-way valve assembly 3. The one-way valve assembly 3 thus comprises the valve seat 3c and the valve member 3a, pushed against the valve seat 3c by the valve spring 3b. The valve seat 3c has an opening, normally blocked by the valve member 3a biased against it, through which fluid can flow when the pressure in the piston chamber is sufficient to overcome the force exerted on the valve member 3a by the valve spring 3b. The first recess 1c and the second recess 1d also provide fluid communication between the piston chamber 2 and the conduit 1a. Suitably, the first recess 1c and the second recess 1d are formed as a part of the conduit, suitably as sections of varied dimensions.

[0025] Advantageously, a piston-pump dispenser according to the invention is arranged in connection with a reservoir 5 that is in fluid communication with the inlet 2a, thus constituting a soap dispenser suitable for use in e.g. sanitary facilities.

Claims

1. A piston pump dispenser for dispensing liquids such as soap, comprising:

- a piston chamber (2);

- an inlet (2a) for providing fluid communication between said piston chamber (2) and a reservoir (5);

- an outlet (1b) in fluid communication with said piston chamber (2) for dispensing said liquid to a user;

- a piston (1) arranged for a reciprocating movement between a depressed position and a retracted position within said piston chamber (2);

- a one-way valve assembly (3) arranged for preventing fluid flow from said outlet (1b) to said piston chamber (2),

wherein a movement of the piston (1) from the retracted position towards the depressed position reduces the volume of the piston chamber (2) and causes fluid to flow from the piston chamber (2) to the outlet (1b), and a movement of the piston (1) from the depressed position towards the retracted position increases the volume of the piston chamber (2) and causes liquid to be drawn from the inlet (2a) to the piston chamber (2),
characterized in that said inlet (2a) is arranged on the piston chamber (2) such that, when the piston (1) is displaced a certain distance from said retracted position towards said depressed position, the piston (1) closes the fluid communication between the inlet (2a) and the piston chamber (2), thus preventing liquid from flowing from the piston chamber (2) to the inlet (2a) when the volume of the piston chamber (2) is decreased.

2. A piston pump dispenser according to claim 1, characterized in that the piston (1) is biased towards its retracted position.

3. A piston pump dispenser according to claim 2, characterized in that a biasing spring (4) is arranged within said piston chamber (2) for biasing the piston (1).

4. A piston pump dispenser according to claim 3, characterized in that the piston (1) comprises a first recess (1c) located on the piston chamber (2) side end of the piston (1), and extending a distance in the longitudinal direction of the piston (1), said first recess (1c) being arranged to accommodate at least a portion of the biasing spring (4)

5. A piston pump dispenser according to claim 1-4, characterized in that the piston (1) is equipped with a conduit (1a) arranged to provide fluid communication between the piston chamber (2) and the outlet (1b).

6. A piston pump dispenser according to claim 5, characterized in that said one-way valve assembly (3) for preventing fluid flow from said outlet (1b) to said piston chamber (2) is arranged on the piston (1), preferably on the piston chamber (2) end side of the conduit (1a).

7. A piston pump dispenser according to claim 6, characterized in that the piston (1) comprises a second recess (1d) extending from the bottom of the first recess (1c) in the longitudinal direction of the piston (1), wherein:

- the first recess (1c) is further arranged to accommodate a valve seat (3c) of a one-way valve assembly (3), said valve seat (3c) being fixed in the first recess (1c) by the biasing spring (4) pushing said valve seat (3c) against the bottom of the first recess (1c), and

- the second recess (1d) is arranged to accommodate a valve member (3a) and a valve spring (3b) of a one-way valve assembly (3), said valve member (3a) being arranged to push against the valve seat (3c) by the valve spring (3b),

wherein said first recess (1c) and second recess (1d) provide fluid communication between the piston chamber (2) and the conduit (1a).

Drawing