Pump assembly

Abstract: A pump assembly for storing and discharging a liquid such as a chemical solution includes a substantially cylindrical container (1) for storing the liquid therein, a pump (2) mounted on one end of the container (1) and having suction port (17) for drawing the liquid from the container and an outlet port for discharging the liquid, and a gasket (4) slidably inserted in the opposite end of the container (1) in contact with the liquid stored in the container (1), for sealing the liquid in the container (1),the gasket (4) being slidable toward the pump (2) when the liquid stored in the container (1) is reduced by the pump (2), A slanted portion (7) is disposed in said one end of the container (1) and has a slanted surface (8) extending continuously from an inner peripheral surface of the container (1) and converging away from the gasket (4), The suction port (17) of the pump (2) communicates with the interior space of the container (1) substantially at a converging end of the slanted surface (8). Any trapped air is collected between the slanted surface (8) and the liquid contained in the container (1), and can be discharged from the container (1) by the pump (2) before the liquid is discharged from the container (1) by the pump (2).

Description: The present invention relates to a pump assembly. In particular, it relates to a pump assembly which has a container for storing a liquid, such as a chemical solution, in isolation from ambient air so that the stored liquid will be protected from being modified, e.g., oxidized, by the air and which can discharge the stored liquid from the container while retaining the liquid in isolation from ambient air. In the prior art, GB-A-2197693 discloses a pump assembly of the type having the features which form the preamble of claim 1. Another known pump assembly is shown in longitudinal cross section in Figure 4 of the accompanying drawings. The pump assembly shown in Figure 4 comprises a substantially cylindrical container a with opposite open ends, a pump b mounted in the upper end of the container a , and a gasket c slidably inserted in the bottom end of the container a . With the pump b mounted in the upper end of the container a , a liquid X, such as a chemical solution, is filled in the container a through the bottom end thereof and the gasket c is inserted into the container a until the gasket c contacts the surface of the liquid X. The liquid X is thus sealed in the container a in isolation from ambient air. After the liquid X is sealed in the container a , the bottom end of the container a is closed by an air-permeable bottom lid d . The pump b may be a pump disclosed in, for example, JP-A-61-263668. When a presser e of the pump b is pressed by, for example, a finger, the pump b draws in the liquid X from the container a through a suction port f and ejects the liquid X from an outlet port g . The suction port f of the pump b which is installed in the upper end of the container a extends through a neck h on the upper end thereof and is immersed in the liquid X. When the liquid X in the container a is drawn and ejected out of the container a by the pump b , the gasket c slides towards the pump b while in contact with the surface of the liquid X as the amount of liquid X in the container a is progressively reduced. Therefore, the liquid X stored in the container a remains sealed, i.e. in isolation from the ambient air, and is prevented from being modified, e.g., oxidized by contact with the ambient air. While the liquid X sealed in the container a remains isolated from the ambient air, air often tends to flow into the container a when the liquid X is introduced into the container a . The air Y, which enters into the container a when it is filled with liquid X, is trapped between the suction port f of the pump b and the neck h and cannot be easily removed from the container a after the liquid X has been sealed in the container a . Therefore, the liquid X in the container a may be oxidized by the trapped air Y. To prevent such oxidization of the liquid X, it has been necessary to replace the air Y with nitrogen gas when the liquid X is sealed. Such a replacing procedure is however tedious and time-consuming. It is an object of the present invention to provide a pump assembly for ejecting a liquid, such as a chemical solution, from a container while isolating the liquid in the container from ambient air, the pump assembly having a mechanism which can easily remove air from the container which is trapped therein when the container is filled with liquid and sealed. According to the present invention, there is provided a pump assembly comprising: a substantially cylindrical container for storing a liquid therein, said container having first and second opposite open ends; a pump mounted at the first end of the container and having a suction port for drawing the liquid from said container and an outlet port for discharging the liquid; sealing means slidably inserted in the second end of the container for sealing the liquid in the container, said sealing means being in contact with the liquid and being slidable towards said pump when the liquid is discharged by said pump; and a slanted portion disposed in said first end of the container and having a slanted surface extending continuously from an inner peripheral surface of said container and converging away from said sealing means, said suction port of said pump communicating with the interior space of said container substantially at the converging end of said slanted surface, characterised in that said sealing means comprises a gasket, and in that said slanted portion has a projection which projects outwardly from said container substantially at said converging end and which has a through hole, said suction port being fitted over said projection and communicating with the interior space of said container through said hole. If air enters the container when the liquid is filled and sealed in the container, it is trapped between the slanted surface and the liquid in the container and is collected along the slanted surface into a region near the converging end of the slanted surface, when the container is turned upside down so that the pump is directed upwardly. When the pump is actuated, the air is drawn along the slanted surface into the suction port and then discharged from the outlet port. Thereafter, the liquid stored in the container is drawn into the suction port and discharged from the outlet port. As the liquid is gradually discharged out of the container, the gasket is caused to slide towards the pump whilst remaining in contact with the stored liquid, which is therefore kept in isolation from ambient air. Because the suction port of the pump is fitted over the projection projecting outwardly from the container substantially at the converging end of the slanted surface and communicates with the interior space of the container through the through hole defined in the projection, the tip end of the suction port is isolated from the interior space of the container by the slanted portion. Thus the tip end of the suction port is prevented from contacting the liquid in the container before the trapped air is completely drained from the container. Consequently, the air trapped in the container can fully be removed. Therefore, any air which is trapped in the container can easily be removed from the container when the pump is operated after the liquid is sealed in the container. Accordingly, the liquid sealed in the container can be stored in the container without being contacted by air. The pump assembly may further comprise an inner plug inserted in the one end of the container, the slanted portion being disposed on an end of the inner plug which faces into the container. The advantage of this is that the pump assembly can be used with a variety of containers when the inner plug is fitted in the end of the container used. Therefore, any trapped air can be removed by the pump from any of these various containers. The slanted surface may be substantially conical in shape. Thus it may easily be formed integrally with the container or the inner plug. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which: FIG. 1 is a longitudinal cross-sectional view of a pump assembly in accordance with the present invention; FIG. 2 is a longitudinal cross-sectional view of a conventional pump which can be used in the pump assembly of FIG. 1; FIG. 3 is a fragmentary, partly exploded cross-sectional view showing the manner in which a liquid can be filled and sealed in the container of the pump assembly of FIG. 1; and FIG. 4 is a longitudinal cross-sectional view of a conventional pump assembly. As shown in Figure 1, a pump assembly comprises a substantially cylindrical container 1 with opposite open ends, a pump 2 mounted on one end (hereinafter referred to as the "upper end") of the container 1 through an adapter 3, for drawing and ejecting a liquid X which is filled in the container 1, a gasket 4 slidably inserted in the other end (hereinafter referred to as the "bottom end") of the container 1 which is filled with the liquid X, and a bottom lid 5 fitted in the bottom end of the container 1 in which the gasket 4 is inserted. The bottom lid 5 has a vent hole 6 through which a space between the bottom lid 5 and the gasket 4 communicates with the exterior of the container 1. The upper end of the container 1 opens outwardly through a neck 7 whose diameter is slightly smaller than the diameter of the barrel portion of the container 1. A hollow inner plug 8 having an open upper end is inserted in the neck 7. The inner plug 8 has a lateral flange 8a on its upper end, which engages the upper end of the neck 7. The inner plug 7 has a substantially conical slanted portion 9 on its lower end, the slanted portion 9 being concentric with a barrel portion of the container 1. With the inner plug 8 fitted in the neck 7, the slanted portion 9 has an inner slanted surface 10 which extends continuously from the inner peripheral surface of the barrel portion of the container 1 and the neck 7 and converges upwardly into a projection 11 projecting upwardly from the centre of the slanted portion 9. The projection 11 has a vertical through hole 12 which communicates with the interior space of the container 1. The adapter 3 is in the form of a hollow cylinder comprising a larger-diameter portion 13 whose lower portion is threaded over the neck 7 of the container 1, with the neck 7 and the inner plug 8 being concentrically disposed in the larger-diameter portion 13. The adapter 3 also has a smaller-diameter portion 14 which is concentrically threaded. An annular member 15 is fixed to the upper inner peripheral surface of the larger-diameter portion 13 of the adapter 3. When the larger-diameter portion 13 is threaded over the neck 7, the annular member 15 and the neck 7 clamp the flange 8a therebetween, thereby securely holding the inner plug 8 in position. Referring to Figure 2, the pump 2 is of a construction which is basically the same as the pump disclosed in Japanese Laid-Open Patent Publication No. 61(1986)-263668. The pump 2 has a vertically movable presser 16 projecting upwardly from the upper end of a casing 17, a suction port 18 integral with the lower distal end of a cylinder 19 which is fixed to the casing 17 and which extends concentrically downwardly from within the casing 17, and an outlet port 20 extending laterally from the upper end of the presser. The smaller-diameter portion 14 of the adapter 3 is threaded into the casing 17 of the pump. In this manner, the pump is mounted at the upper end of the container 1. The suction port 18 of the pump is fitted over the projection 11 such that the lower tip end of the suction port 18 abuts against the upper surface of the slanted portion 9 substantially near the converging end of the slanted surface 10 (see Figure 1). The presser 16 is normally urged to move upwardly by a spring 21 disposed in the cylinder 19. The cylinder 19 defines therein a pump chamber 22 which can be pressurized when the presser 16 is depressed. The interior space of the outlet port 20 communicates with the pump chamber 22 through a valve 23 which is opened when the presser 16 is depressed. The interior space of the suction port 18 communicates with the pump chamber 22 through a valve 24 which is opened in response to a reduction in the pressure in the pump chamber 22 when the presser 16 returns to its original position under the bias of the spring 21. When the presser 16 of the pump 2 is depressed by a finger and then released so as to return to its original position, the liquid X stored in the container 1 is drawn through the suction port 18 and the valve 24 into the pump chamber 22. When the presser 16 is depressed again, the liquid X which has been drawn into the pump chamber 22 is ejected out of the outlet port 20 through the valve 23. To fill and seal the liquid X in the container 1, the inner plug 8 is first fitted in the neck 7. Then the container 1 is turned upside down to direct the upper end thereof downwardly. Then, the liquid X is filled in the container 1 through the bottom end thereof which is now positioned upwardly. The gasket 4 is then inserted into the container 1 through the bottom end until the gasket 4 is brought into contact with the surface of the liquid X. The liquid X is now sealed in the container 1. Subsequently, the bottom lid 5 is fitted into the bottom end of the container 1, thereby closing the bottom end. The container 1 is reversed again to direct its upper end upwardly, as shown in Figure 1. Alternatively, as shown in Figure 3, the gasket 4 is inserted in the bottom end of the container 1, and the bottom end thereof is closed by the bottom lid 5. Thereafter, the liquid X is filled in the container 1 through the neck 7 on the upper end thereof, after which the pump 2 is mounted at the upper end of the container 1 via the adapter 3, thus sealing the liquid X in the container 1. While the liquid X is being filled and sealed in the container 1 as described above, air Y may be trapped in the container 1. When the upper end of the container 1 is directed upwardly as shown in Figure 1, the air Y which is trapped in the container 1 rises in the liquid X and is collected along the slanted surface 10 toward the converging end thereof toward a region below the suction port 18 of the pump 2. When the presser 16 is depressed and released so as to return to its original position, the air Y is drawn along the slanted surface 10 through the suction port 18 into the pump chamber 22. When the presser 16 is depressed again, the trapped air Y is discharged from the pump chamber 22 through the outlet port 20. This process is repeated to discharge the air Y gradually from within the slanted portion 9. The gasket 4, while being held in contact with the liquid X, is caused to slide in the container 1, forcing the liquid X towards the suction port 18. Thereafter, the liquid X is drawn from the suction port 18 and ejected from the outlet port 20. At this time, the liquid X in the container 1 is sealed in the container 1 while being isolated from, i.e., out of contact with, the ambient air. With the pump assembly of the present invention, after the liquid X is filled and sealed in the container 1, the pump 2 is operated to discharge the air Y which may be trapped in the container 1 when the liquid X is filled in the container 1. Therefore, the liquid X is stored in the container 1 in isolation from the ambient air, and can be discharged from the container 1 when necessary. Since the tip end of the suction port 18 is isolated from the interior space of the container 1 by the slanted portion 9, the tip end of the suction port 18 is prevented from contacting the liquid X in the container 1, thus not starting to draw any liquid X from the container (1), before the air Y is completely expelled from said container 1. Consequently, the air Y trapped in the container 1 can be fully removed. The slanted portion 9 for collecting any trapped air Y into the region directly beneath the suction port 18 is provided by the inner plug 8 which is fitted in the container 1. Therefore, the pump assembly shown in Figures 1 and 3 may be incorporated in a container which has no slanted portion on its upper end, as with the container 1, for the removal of trapped air.

Claims: A pump assembly comprising: a substantially cylindrical container (1) for storing a liquid (X) therein, said container (1) having first and second opposite open ends; a pump (2) mounted at the first end of the container (1) and having a suction port (18) for drawing the liquid (X) from said container (1) and an outlet port (20) for discharging the liquid (X); sealing means slidably inserted in the second end of the container (1) for sealing the liquid (X) in the container (X), said sealing means being in contact with the liquid (X) and being slidable towards said pump (2) when the liquid (X) is discharged by said pump (2); and a slanted portion (9) disposed in said first end of the container (1) and having a slanted surface (10) extending continuously from an inner peripheral surface of said container (1) and converging away from said sealing means, said suction port (18) of said pump (2) communicating with the interior space of said container (1) substantially at the converging end of said slanted surface (10), characterised in that said sealing means comprises a gasket (4), and in that said slanted portion (9) has a projection (11) which projects outwardly from said container (1) substantially at said converging end and which has a through hole (12), said suction port (18) being fitted over said projection (11) and communicating with the interior space of said container (1) through said hole (12). A pump assembly as claimed in claim 1, further comprising an inner plug (8) inserted in said first end of the container (1), said slanted portion (9) being disposed on the end of said inner plug (8) which faces into said container (1). A pump assembly as claimed in claim 1 or 2, characterised in that said slanted surface (10) is substantially conically shaped.

Inventors: SUGITA KOICHI, SUGITA, KOICHI
Applicants: TOP KK, KABUSHIKI KAISHA TOP
Application year: 1990
Main classification: B05B11
IPC codes: B05B11