GB2051969A

GB2051969A - A Liquid Metering Device

Info

Publication number: GB2051969A
Application number: GB8002593A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-06-21
Filing date: 1980-01-25
Publication date: 1981-01-21
Also published as: DE3005779A1; FR2459458A1; ES481770A1; GB2051969B; FR2459458B1; DE3005779C2

Abstract

A liquid metering device comprising a pumping chamber 16 communicatable with a suction duct 5 and a discharge duct 24, a main piston 21 housed in said pumping chamber, a member 27 having a sealing portion 28 for the discharge duct 24 and an opposed portion as a secondary piston 29 housed in a counterchamber 19 in which there are resilient means 34 biassing the secondary piston 29, there being first passage means 39, 40 for establishing a direct communication between the suction duct 5 and the pumping chamber 16 and second passage means 41, 42 placing the interior space of the container in direct communication with the counterchamber 19. <IMAGE>

Description

SPECIFICATION A Liquid Metering Device The invention relates to improvements in liquid metering devices of the type which may be connected to interior space of the container holding the liquid to be metered and which comprises a housing, a main cylinder defining a pumping chamber communicatable with a suction duct and with a discharge duct, a main piston slidably housed in said main cylinder and having a valve seat connected to said discharge duct, a selective opening member having a sealing portion associated with said valve seat and an opposed portion forming a secondary piston, to the rear surface of which there is applied the pressure from the pumping chamber and the front surface of which is biassed by resilient means, and a secondary cylinder in which the secondary piston is slidingly housed, defining therewith a counterchamber housing said resilient means.

Devices of the above described type are commonly used for metering small amounts of liquid in general. Frequently such devices, conveniently associated with a spray nozzle connected to the discharge duct, are used as sprays or vapourisers for perfumes, deodorants or other perfumery products and cosmestics.

German patent no. 1.290.043 discloses a spray device of the type described in which the secondary piston carries a migrating valve, the opening of which puts the counterchamber housing the resilient means in direct communication with the pumping chamber, whereby the liquid to be sprayed coming from the suction duct of necessity crosses through said counterchamber prior to reaching the pumping chamber. Consequently, several disadvantages arise. On the one hand, the liquid contacts the resilient means, normally a metal spring, whereby the liquid may be contaminated by the spring metal and the latter may be corroded by the liquid. On the other hand, the volume of the counterchamber has a more or less parasitic effect, reducing the volumetric efficiency of the pump and making its priming difficult when it is wanted to operate the device and its chambers empty of liquid and full of air.

U.S. patent no. 4.025.046 discloses a further spray device of the type described in which, in spite of the secondary piston not having a migrating valve, direct communication is also established alternately between the counterchamber housing said resilient means and the pumping chamber. Thus, the operation of the device requires that the liquid of necessity should fill said counterchamber, whereby the liquid also contacts the spring metal and the volume of the liquid contained in the counterchamber is associated in parasite fashion with the pumping chamber volume. Thus, this device does not overcome the abovementioned disadvantages either.

It is an object to overcome the abovementioned disadvantages and provide further advantages which will become manifest hereinafter. The device of the invention is characterised in that it comprises a check valve situated upstream of the pumping chamber and opening in the suction direction, first passage means placing the suction duct in direct communication with the pumping chamber through said check valve and second passage means placing the container interior space and the counterchamber housing the resilient means in direct communication, so that the pumping chamber and the counterchamber communicate with the container interior space through separate ways.

The invention also contemplates that the secondary cylinder should comprise an insert mounted fixedly inside the device housing, facilitating the formation of the said passage means and of the check valve.

Certain preferred embodiments of the invention are illustrated in the drawings, in which: Figure 1 is an elevational view, partly in longitudinal section, of a device according to the invention mounted on a container holding liquid and having a spray nozzle; Figure 2 shows the same device, totally in longitudinal section and on a larger scale; Figure 3 is a cross sectional view along the line Ill-Ill of Figure 2; Figure 4 is a longitudinal section view of an alternative embodiment of the lower portion of the device of the invention Figures 5 and 6 are cross sectional views along the lines V-V and VI--VI of Figure 4; Figure 7 is a longitudinal section view of yet a further embodiment of the device according to the invention; and Figure 8 is a cross sectional view along the line VIll-VIll of Figure 7.

In Figure 1 , the device, generally indicated with the numeral 1, is connected to the interior space 2 of a container 3 containing the liquid 4 to be metered and, moreover, in this case, be sprayed.

The liquid penetrates through the suction duct or probe 5, passes through the device 1 and reaches an upper head pipe 6 where there is fitted a spray head 7 having a nozzle 8 of known type, which is reached by the liquid through a duct 9. As is usual, the spray head 7 has an upper surface 10 appropriately shaped to receive the user's finger so that the device may receive the reciprocating movement required for pumping. The device 1 engages the neck 11 of the container 3 by way of a metal sleeve 12 suitably clinched over said neck and over a flange 13 of the device.

The internal construction of the device is to be seen in Figures 2 and 3. The housing 14 has a main cylinder 1 5 in the upper portion thereof, in the interior of which there is a pumping chamber 16, and a cylindrical portion 17 of lesser diameter housing an insert 18. This insert 18 has the function of a secondary piston and the counterchamber 1 9 is formed in the interior thereof. The housing 14 extends downwards in a tubulature 20 into which the probe 5 is inserted.

A main piston 21 is slidably mounted in the main cylinder 1 5 and limits the pumping chamber 1 6 at the top end thereof. In a way known per se an upper edge 22 and a lower edge 23 applied against the inner wall of the main cylinder 15 ensure the tightness of the main piston 21, both on its upward stroke and on its downward stroke.

The upper head pipe 6 of the device is an integral part of the main piston 21 and forms a discharge duct 24 having at the lower end thereof a passage 25 followed by a valve seat 26.

Crossing through the pumping chamber 1 6 there is a selective opening member 27 extending upwardly with a sealing portion 28 so shaped as to be engageable with valve seat 26. At the lower end thereof, the selective opening member 27 is provided with a secondary piston 29, slidably mounted in the insert 1 8 forming the secondary cylinder. Said member 27 is hollowed out longitudinally in 30 from one end to save material and terminates in a downwardly extending tubular extension 31.

The insert 1 8 is mounted fixedly as being a press fit in the cylindrical portion 1 7 of the housing 14 and is formed by a substantially cylindrical side wall 32 and a bottom wall 33. The counterchamber 19 which is limited at the upper end thereof by the secondary piston 29 and at the lower end thereof by the bottom wall 33 of the insert, houses a helical spring 34 mounted under compression between said secondary piston 29 and said bottom wall 33, the tubular extension 31 of member 27 serving to facilitate assembly and centering of the spring 34.

Between the cylindrical portion 1 7 and the lowerturbulature 20 of the housing 14 there is a shoulder 35 in the interior of which there is a recess 36 receiving a cup shaped stopper member 37 the bottom of which engages an annular seat 38. Thus a fixed, not migratory, check valve is constituted, which is located downstream of the probe 5 and upstream of the pumping chamber and which opens in the suction direction.

To provide for direct communication between the suction duct or probe 5 and the pumping chamber 1 6 there are passage means constituted by a longitudinal passage 39 and a transverse passage 40. In Figures 2 and 3, the longitudinal passage 39 is shown as being formed between the outer surface 32a of the side wall 32 of the insert 1 8 and the inner surface 1 7a of the cylindrical portion 17 of the housing 14, thanks to a longitudinal groove cut in said inner surface 17a. In turn the transverse passage 40 is formed between the outer surface 33a of the bottom wall 33 of the insert and the inner surface 35a of the housing shoulder 35, thanks to a radial groove cut in said outer surface 33a.It will be understood that in a further embodiment of the device (not shown), the cylindrical portion 1 7 and the insert 1 8 could be an integral part and that a bore of appropriate shape could be disposed inside the walls of said part to establish direct communication from the recess 36 to the pumping chamber 16.

On the other hand, to provide for direct communication from the counterchamber 1 9 and the interior space 2 (Figure 1) of the container there are passage means constituted by an opening 41 of the insert 18 and a corresponding orifice 42 in the wall of shoulder 35 of the device casing.

In the example shown in Figures 4 to 6, the secondary cylinder is formed by the insert 11 8 comprising a side wall 132 and a bottom wall 133. Said insert 118 is mounted in the cylindrical portion 17 of the device casing and the side wall 132 thereof is provided with longitudinal ribs 11 8a so dimensioned that between the outer surface 1 32a of the side wall and the inner surface 1 7a of the cylindrical portion 17, there are formed longitudinal ducts 1 39 which, in a way not shown, debouch in the pumping chamber 16.

Crossing radially through the bottom wall 133 there are radially extending ducts 140 connecting the recess 36 with the longitudinal ducts 1 39 and in this way, in cooperation with said longitudinal ducts 139, establishing direct communication from the probe 5 to the pumping chamber 16.

Moreover, through an orifice 141 through the bottom wall 1 33 and a corresponding orifice 142 in the shoulder 35 there is established direct communication between the counterchamber 1 9 and the container interior. In this embodiment, the check valve is constituted by the sealing ball 137 disposed in the recess 36 and bearing against the annular seat 38.On the other hand, the bottom wall 1 33 of the receptacle insert 118 is provided with a tubular extension 143 directed towards the probe 5, corresponding to a mouth 144 disposed inside the shoulder 35 and connected to the probe 5 via the check valve 38, 137. Thanks to retaining means 145, comprising an annular rib and a mating annular groove, provided respectively in the tubular extension 143 and in the mouth 144, after the device has been assembled, the insert 11 8 is properly retained within the cylindrical portion 17 of the casing.

In the embodiment illustrated in Figures 7 and 8, the lower tubulature 220 of the device does not form part of the casing 14, but belongs to a mushroom shaped member whose head 244 is inserted in the bottom of the housing cylindrical portion 17 and retained in place by annular ribs 246 and 247. In the centre of the head 244 there is a recess 36 for a valve ball 237 which, together with the annular seat 38, forms the check valve.

Between the head 244 and the cylindrical portion 17 there is an annular space 239a forming a manifold for radial ducts 240 which connect the recess 36 with the longitudinal ducts 239 formed between the side wall 232 of the insert 21 8 and the cylindrical portion 1 7. The lower tubulature 220 extends freely outwards through a circular window 248 in the bottom of the cylindrical portion 17. The bottom wall 233 of the insert 218 is provided with a centre extension 243 which mates with the mouth of the recess 36 in the head 244 and thanks to retaining means 245, constituted by mating annular rib and groove, in this embodiment also the insert 218 is held immovable once the device is assembled.The direct communication between the counterchamber 19 and the interior of the container is established by an orifice 241 of the bottom wall 233, a corresponding orifice 242 in the head 244 and the circular window 248.

The operation of the device will be described hereinafter with reference to Figures 2 and 3, on the assumption that it is already primed, in other words, that the ducts and chambers for pumping and flow of the liquid are already full of liquid. In the position illustrated in Figure 2, the liquid fills the umping chamber 16, as well as the probe 5, the recess 36, the transverse and longitudinal ducts 40, 39, respectively, the passage 25 and the discharge duct 24.Then, if the spray head 7 mounted on the upper head pipe 6 is pushed downwards, both the main piston 21 and the secondary piston 29 are forced downwards and, in a known way, because of the difference in diameter between the main piston 21 and the secondary piston 29, the liquid contained in the pumping chamber 16 is subjected to an increasing pressure so that when the pressure on the rear face of the secondary piston 29 reaches a certain level, a downwardly acting force superior to the elastic reaction of the spring 34 against the front face of said secondary piston 29 is created.

Consequently the spring 34 gives way, the seal 28 is moved away from the valve seat 26 and the pressurised liquid in the pumping chamber 16 flows through the passage 25 and discharge duct 24 to be sprayed through the nozzle 8 of the spray head 7. As the main piston 21 moves downwards to the end of its downward stroke, almost all the liquid in the pumping chamber 16 is forced out in a metered amount in spray form. It may be seen that the volumetric efficiency of the pump will be high, because the dead spaces filled with liquid are minimal, since they comprise practically only the volume of the ducts and passages downstream of the check valve 37-38 plus the residual volume in the pumping chamber.

At the end of the downward stroke, the user releases the spray head 7, whereby the spring 34 tends to return to its original state and the secondary piston 29 starts to rise. The pressure in the pumping chamber 1 6 drops, whereby the sealing portion 28 reengages the seat 26 and closes the valve affording passage to the spray head 7. Almost simultaneously the main piston 21 rises also and a depression is created in the pumping chamber 1 6 such that the check valve 37-38 opens and the liquid in the container is sucked through the probe 5 to refili the pumping chamber 1 6 until the latter recovers its original volume, namely, until the device returns to the position illustrated in Figure 2.

With respect to the counterchamber 1 9 containing the spring 34, it is observed that its volume is, of necessity, relatively large with respect to the volume of the pumping chamber 16, since such volume is determined by inescapable dimensional sizes, imposed by the size that the secondary piston 29 must have and by the resilient stress and the strength that the spring 34 must have. But, since thanks to the invention the pumping chamber 16 and the counterchamber 1 9 are never in direct communication, but are communicated separately with the interior 2 of the container 3, the relative large volume of the counterchamber 19 may not have any perturbating effect on the dynamics or on the pumping of the liquid to be metered and sprayed. It should also be highlighted that, in accordance with the invention, the variations of volume of the counterchamber during the reciprocating movement of the secondary piston 29 take place at the expense of the ingress and egress of air, alone or mingled with liquid vapours from the interior space 2. The air flows in and out freely through the aperture 41 and orifice 42 without causing practically any resistance or head loss liable to retard the pumping movements. At the same time, the spring 34 is generally protected from direct, extended contact with the liquid in the container, whereby the aforesaid disadvantages of contamination of the liquid or of corrosion of the spring metal are avoided or greatly reduced.

Claims

1. A liquid metering device of the type which may be connected to the interior space of the container holding the liquid to be metered and which comprises a housing, a main cylinder defining a pumping chamber communicatable with a suction duct and with a discharge duct, a main piston slidably housed in said main cylinder and having a valve seat connected to said discharge duct, a selective opening member having a sealing portion associated with said valve seat and an opposed portion forming a secondary piston, to the rear surface of which there is applied the pressure from the pumping chamber and the front surface of which is biassed by resilient means, and a secondary cylinder in which the secondary piston is slidingly housed, defining therewith a counterchamber housing said resilient means, a check valve situated upstream of the pumping chamber and which opens in the suction direction, first passage means arranged to place the suction duct in direct communication with the pumping chamber through said check valve and second passage means arranged to place the container interior space and the counterchamber housing the resilient means in direct communication, so that the pumping chamber and the counterchamber can communicate with the container interior space through separate ways.

2. A liquid metering device as claimed in claim 1, wherein the secondary cylinder comprises an insert fixedly mounted in the interior of the housing of the device.

3. A liquid metering device as claimed in claim 2, wherein said first passage means comprise at least one longitudinal portion consisting of a duct disposed between the outer surface of the side wall of the insert and the inner surface of the device housing.

4. A liquid metering device as claimed in claim 2, wherein said first passage means comprise at least one transverse portion consisting of a duct disposed between the outer surface of the bottom wall of the insert and the inner surface of a shoulder in the device housing.

5. A liquid metering device as claimed in claim 2, wherein said first passage means comprise at least one transverse portion consisting of a radial orifice disposed in the bottom wall of the insert.

6. A liquid metering device as claimed in claim 2, wherein said second passage means comprise an opening in the insert and a corresponding orifice in the wall of the device housing.

7. A liquid metering device as claimed in any one of claims 2 to 6, wherein the check valve is situated in a recess limited at the top thereof by the bottom wall of the insert.

8. A liquid metering device as claimed in claim 2, wherein the insert is provided with an extension in the bottom thereof directed towards the suction duct and a mouth connected to the suction duct and adapted to receive and hold said extension, the assembly formed by said extension and said mouth defining a recess for the check valve.

9. A liquid metering device as claimed in claim 8, wherein the mouth receiving and retaining the extension of the insert bottom wall is a part of the device housing.

10. A liquid metering device as claimed in claim 8, wherein the mouth receiving and retaining the extension of the insert bottom wall is part of a separate part comprising a tubulature for the suction duct and is provided with means retaining it in the device housing.

11. A liquid metering device substantially as hereinbefore described with reference to and as shown in Figures 1 to 3, Figures 4 to 6 or Figures 7 and 8 of the accompanying drawings.