US3889706A

US3889706A - Float-controlled valve

Info

Publication number: US3889706A
Application number: US435966A
Authority: US
Inventors: Jan Olof Wilhelm Wallin
Original assignee: PX Petrocontrol AB
Current assignee: PX Petrocontrol AB
Priority date: 1973-02-21
Filing date: 1974-01-23
Publication date: 1975-06-17
Anticipated expiration: 1992-06-17

Abstract

A float-controlled valve for separating a liquid from at least one other liquid having a lower density than the first liquid. The float of the valve is connected to a flexible diaphragm and is balanced so as to lift a portion of the diaphragm from an outer seat face and thereby open a discharge opening when the float is buoyantly supported by the heavier liquid, whereas the diaphragm will close the discharge opening in other cases. A central support plate is disposed centrally in the discharge opening for supporting the diaphragm, thus enabling the discharge of large volumes of the heavier liquid while any liquid is prevented from passing through the valve.

Description

O United States Patent [191 Wallin June 17, 1975 FLOAT-CONTROLLED VALVE 3,473,531 10/ I969 Tatham 251/294 X 3,610,273 10 197] R ll [75] Inventor: Jan Olof Wilhelm Wallin, Taby, ussc 137/525 3 X Sweden Primary Examiner-Alan Cohan Assigneel PX Petrocontrol AB,Taby, Sweden Attorney, Agent, or Firm-Wenderoth, Lind, & 22 Filed: Jan. 23, 1974 mack [21] Appl. No.: 435,966 [57] ABSTRACT A float-controlled valve for separating a liquid from at [30] Fore'gn Apphcatmn pnomy Data least one other liquid having a lower density than the Feb. 21, Sweden first The float of the alve is connected to a flexible diaphragm and is balanced so as to lift a portion of the diaphragm from an outer seat face and 251/294 thereby open a discharge opening when the float is Int. Cl. buoyantly supported the heavier whereas 0f Search the dia hragm close the discharge Opening in 002 other cases. A central support plate is disposed centrally in the discharge opening for supporting the dia- [56] References Cited phragin, thus enabling the discharge of large volumes UNITED STATES PATENTS of the heavier liquid while any liquid is prevented 913,000 2/1909 Embree 137/172 from Passing through the valvel,955,742 3/1935 Linnmann 137/172 X 3,425,447 2/1969 McCullough 251/294 x 5 2 Draw Fgures F LOAT-CONTROLLED .VALVE BACKGROUND OF THE INVENTION The invention relates to a float-controlled valve for separating a liquid, such as water, from at least one other liquid, such as oil, having a lower density than the first-mentioned liquid, wherein the valve is disposed in the lower part of a generally closed housing means, such as a tank, and a valve member is connected to a float, the dimensions and the density of which are adapted so as to cause the valve member to open a discharge opening when the float is buoyantly supported by the heavier liquid, whereas the valve member is adapted to close the discharge opening in other cases.

Such valves are known e.g. from the US. Pat. No. 2,957,490, 3,021,861, and 3,154,091, and they are used among other applications for preventing petroleum products from being discharged into draining systems and polutting the recipients.

When storing or handling petroleum products one must take into account that leakage or spillage may occur and, therefore, the authorities in Sweden as well as in other countries have prescribed that security apparatus must be installed which will prevent an uncontrolled dispersion of petroleum products, even under unfavourable conditions. In this connection, it has turned out that one cannot rely on a continuous human supervision, such as a periodical emptying of drainage vessels or the cleaning of filters. The ideal apparatus would be one which operates automatically without human control under normal conditions and only has to be cleaned or checked in case of serious leakage or spillage. The known valves do not comply with this aim and they suffer from certain drawbacks.

In order to enable the discharge of large volumes of water, e.g. when rain falls, and simultaneously prevent lesser amounts of petroleum products, which have leaked or been spilled out, from flowing out with the water, the valve device must be provided with such a valve member and such a valve seat that a great water flow is permitted to pass freely through the valve and that the suction effect created in connection therewith and tending to force the valve member against the valve seat does not cause the valve to close. As a rule, the known valves do not meet with this requirement, and sometimes they suddenly close when the pressure head reaches only a moderate value. Naturally, an overflow of liquid and the ensuing damage may be caused thereby. Further, the known valves have a fairly complicated structure and, therefore, the manufacturing costs are rather high.

SUMMARY OF THE INVENTION Thus, the purpose of the invention is to create a floatcontrolled valve of the kind referred to above which does not suffer from the indicated drawbacks. According to the invention this is accomplished by providing that the float of the valve is connected to a flexible diaphragm and is balanced so as to lift a portion of the diaphragm from an outer seat face and thereby open a discharge opening when the float is buoyantly supported by the heavier liquid, whereas the diaphragm will close the discharge opening in other cases. A central support plate is disposed centrally in the discharge opening for supporting the diaphragm, thus enabling the discharge LII of large volumes of the heavier liquid while any lighter liquid is prevented from passing through the valve.

The valve according to the invention can be used e.g.

in draining gutters in cellars with oil tanks, at embankments surrounding out-door oil tanks (where also great volumes of rain water must be removed), and in connection with petrol or oil segregation tanks at gas stations and motor repair shops, etc. v

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTION In the draining gutter l, which includes a partition wall 2, operating as a draining trap, and a draining pipe 3, there is mounted a valve casing 4. A support ring 5 covers the opening of the gutter around the valve casing and sealingly engages with the upper edge 6 of the gutter as well as with the wall of the valve casing. The valve casing has an upper cover 7 with an upper opening 8 for letting out air and larger side openings 9 which could possibly be provided with nets or the like and through which e.g. a mixture of water and oil can flow into the valve casing (see arrows A in FIG. 1).

A float member 10 floats in the valve casing and is connected to the valve member by means of nylon cords 11. The valve member consists of a diaphragm 12 formed as a circular disc and made of a comparatively flexible material. The valve seat comprises a circular outer seat face in the form of a V-ring 13 which is pressed onto a cylindrical sleeve 14 with a recess 15 for receiving the V-ring 13. The sleeve 14is open at its lower end and forms an outlet opening 16 for the valve casing 4 communicating with the inside of the draining gutter.

At a horizontal bar 17 diametrically secured inside the sleeve 14 a central, circular support disc 18 is rigidly mounted on an intermediary member 19. which is preferably integral with the bar 17. The support disc 18 has a central hole 20 and the intermediary member a corresponding blind hole 21 with an inner thread. This arrangement permits the diaphragm 12, which is also provided with a central hole, to be secured to the central portion of the support disc 18 by screwing a screw 22 into the blind hole 21 of the intermediary member. Preferably, a washer 23 is positioned between the screw head and the diaphragm 12.

When the screw 22 has been screwed in, the diaphragm is supported on the support disc 18 and, with its circumferential parts, on the V-ring 13. Thus, in this position, the diaphragm sealingly engages with the V- ring 13, and the seal becomes even more effective, if the diaphragm is loaded under liquid pressure from above.

On the other hand, when the-water level in the valve casing rises and the float pulls the nylon cords upwards, those parts12' of the diaphragm 12 which are secured to the cords are also lifted upwards, whereby the corresponding portions of the V-ring 13 forming the outer seat face are disengaged from diaphragm 12 and water is permitted to flow down through the annular passage between the support disc 18 and the V-ring l3 and further down into the inside of the draining gutter via the sleeve 14. It should be noted that the bar is comparatively narrow and does not interfere severely with the discharge flow.

In the embodiment shown two nylon cords l l are fastened at opposite locations to the circumferential portion of the diaphragm 12. Thus, in its lifted position, the diaphragm takes the form of a U or a V in all planes parallel to the section plane shown on the drawing, i.e. the diaphragm does not disengage from the total seat face of the V-ring. Of course, with a larger number of symmetrically arranged cords or other connection means, it is possible to achieve a total disengagement from the seat face. Moreover, within the scope of the invention, the diaphragm 12 may be secured at any part of its circumferential portion instead of the central fastening by means of the screw 22, in which case, however, the different parts of the valve (the diaphragm 12, the seat ring 13 and possibly also the support disc 15) are not circular but polygonal, e.g. squared, in shape. The important thing is that the diaphragm 12 is sup ported by the support disc 18 and that at least a portion of its circumference can be lifted up, whereby the corresponding parts of the outer seat face are disengaged. In such a case the diaphragm 12 may be connected to the float at only one point oralong a line.

The valve operates in the following way: In case only water, possibly polluted with e.g. sand and dirt particles or the like, flows into the valve casing through the upper side openings 9, the water level in the valve casing 4 rises from the level shown in FIG. 1 corresponding to the rest position of the device (in the embodiment shown the density and size of the float are so adapted that the valve is then in a closing position but will open upon a small increment of the buoyancy of the float the balance may also be such that the valve is open at rest but will close upon a small reduction of the buoyancy of the float), whereby the float by means of the cords 11 lifts the circumferential parts of the diaphragm 12 and thus opens the valve, so that the water may flow down into the inside of the draining gutter and thereafter out through the draining pipe 3. Now, it is important that the valve is maintained in open position even if large amounts of water (under great pressure heads) flow through the valve casing. The problem which has been observed for previously known valves, i.e. that the suction effect occuring underneath the valve member in case of a great flow of water will cause the valve to close although a proper valve operation is very significant in this case (the risk of overflow), is eliminated in an unexpected manner by means of the valve according to the invention. Tests have shown that not even comparatively great pressure heads and water flows will cause the inventive valve to close.

If, alternatively, a lighter liquid than water, such as oil, or a mixture of water and a lighter liquid flows into the valve casing 4, the lighter liquid will be positioned in the upper part of the valve casing 4. If now the amount of lighter liquid is so great that the float is predominantly surrounded by the lighter liquid, the buoyancy of the float will be reduced, thereby causing the closure of the valve. This may occur incase of an accident, such as a substantial leakage, and then the oil or the like which has leaked out must be removed in any conventional manner from the closed housing means in which the valve is mounted (e.g. an embankment surrounding an out-door oil tank or a cellar wherein an oil tank is installed). However, in case additional water flows into the valve casing, the water will displace (upwardly) the lighter liquid, whereby the float regains its greater buoyancy and the water is permitted to be discharged as the valve opens again. Thus, water can always be discharged through the valve casing, whereas any lighter liquid is prevented from flowing out into the draining system. In those situations where only small amounts of the lighter liquid enter the valve casing, as the case will be at gas stations or motor repair shops where spillage of gas and oil is unavoidable, the spillage will be accumulated in the upper part of the valve casing and can be removed by a known method, e.g. by inserting a suction tube through the upper hole 8 normally used for evacuating air.

Modifications and structural variations may be made within the scope of the invention. For instance, the V- ring 13 may be replaced by an O-ring.

What I claim is:

1. In a float-controlled valve for separating a liquid, such as water, from at least one other liquid, such as oil, having a lower density than the first-mentioned liquid, wherein the valve is disposed in the lower part of a generally closed housing means, such as a tank, the valve including a valve member connected to a float the density and size of which are adapted so as to cause the valve member to open a discharge opening of the valve when the float is buoyantly supported at least partially by the heavier liquid, but to cause the valve member to close the discharge opening in other cases, the improvement wherein:

said discharge opening being defined between an outer, substantially circumferential seat face defining therein a space and an inner support plate which is positioned in said space and which is coaxially fixedly mounted with respect to said outer seat face, the outer periphery of said inner support plate extending radially to a position adjacent said outer seat face to form therebetween a generally continuous circumferential passage;

said valve member comprising a diaphragm made of a flexible material and being supported on said support plate, said diaphragm, when the valve is in the closed position, sealingly engaging with said outer seat face; and

connecting means linking said float with said diaphragm at a circumferential portion thereof, such as at least one circumferential point or line thereof, for disengaging at least a portion of the circumferential part of said diaphragm from said outer seat face to open said valve when said float is buoyantly supported at least partially by the heavier liquid.

2. A valve as claimed in claim 1, wherein said diaphragm is secured to said support plate at the upper face thereof.

3. A valve claimed in claim 1, wherein said outer seat face is circular and is formed by a sealing ring secured to a sleeve.

4. A valve as claimed in claim 1, wherein said support plate is mounted at the inside of a sleeve and has therein a central hole forming the opening of an aligned bore having an inner thread, said diaphragm being secured to said support plate by means of a screw which is screwed into said bore.

5. A valve as claimed in claim 1, wherein the outer seat face is inclined radially upwardly.

Claims

1. In a float-controlled valve for separating a liquid, such as water, from at least one other liquid, such as oil, having a lower density than the first-mentioned liquid, wherein the valve is disposed in the lower part of a generally closed housing means, such as a tank, the valve including a valve member connected to a float the density and size of which are adapted so as to cause the valve member to open a discharge opening of the valve when the float is buoyantly supported at least partially by the heavier liquid, but to cause the valve member to close the discharge opening in other cases, the improvement wherein: said discharge opening being defined between an outer, substantially circumferential seat face defining therein a space and an inner support plate which is positioned in said space and which is coaxially fixedly mounted with respect to said outer seat face, the outer periphery of said inner support plate extending radially to a position adjacent said outer seat face to form therebetween a generally continuous circumferential passage; said valve member comprising a diaphragm made of a flexible material and being supported on said support plate, said diaphragm, when the valve is in the closed position, sealingly engaging with said outer seat face; and connecting means linking said float with said diaphragm at a circumferential portion thereof, such as at least one circumferential point or line thereof, for disengaging at least a portion of the circumferential part of said diaphragm from said outer seat face to open said valve when said float is buoyantly supported at least partially by the heavier liquid.