US1977039A - Foot valve - Google Patents

Description

Oct. 16,1934.

W. H. D. BRoUsE FOOT VALVE Filed Feb. 4, 1951 Patented Oct. 16, 1934 more!) sures ears i FiCE FOOT VALVE Application February 4, 1931, Serial No. 513,365

8 Claims.

The principal objects of the invention are, to overcome the difficulties met with in attempting to maintain a constant level of fluid in fluid dispensing systems, thereby facilitating accurate measurement at all times, and further, to provide a valve of the mercury seal type which will allow the escape of pressures in excess of the normal hydrostatic head, and will ensure the maintenance of an effective body of mercury in i the sealing pocket.

The principal features of the invention consist in the novel construction of a tapered tubular valve engaging a tapered tubular inlet and sealed at the bottom end in a mercury seal, whereby the mercury if forced upwardly from the sealing pocket by an excessive back pressure is intercepted and returned to the sealing pocket.

In the accompanying drawing,-Figure 1 is a verticalmid-sectional view of a foot valve constructed in accordance with this'invention showing the valve in the closedposition.

Figure 2 is a view similar to Figure 1 showing the valve open.

Figure 3 is a cross section taken on the line 3-3 of Figure 1.

In the operation of fluid dispensing apparatus, such as gasoline pumps, it is found that the ordinary types of check valves, used at the bottom of the supply pipe leading from the tank,

30, will not retain the column of liquid in the stand pipe, pump and meter with the result that air pockets are formed and when the device is used, after resting for a substantial period the air pockets created therein hinder an accurate meas 35, urement of the fluid.

The most successful means proposed for over-;

coming this detrimental defect is a mercury sealed valve in which a tapered tubular valving member encloses a tapered tubular inlet and is sealed in a body of mercury arranged at the bottom of the valving member but it is found that conditions arise in the practical use of these valves that destroy the sealing effect of the mercury and in fact remove the mercury at least in part,

from the sealing pocket.

The present invention has eifectively eliminated these difficulties' and the improved construction is illustrated in the accompanying drawing in which the body of the valve is in the form of a metal cylinder 1 having feet 2 extending from the bottom end to support the cylinder clear of the bottom of the tank in which the valve is placed.

A tapered tube 3 is formed with a flange 4 at the bottom end which is securely sealed to the inner wall of the cylinder 1 above thefeet 2. The upper end 5 of the tube 3 is open.

A tapered tubular valve member 6 is arranged to encircle thetube 3 and is provided with an enlarged closed end 7 which encloses the open upper end 5 of the tube 3, the enlargement extending well below the upper end of said inner tube and forminga recess surrounding the inlet tube.

A small tube 8 pierces the underside of the enlarged end '7 of the valve 6 and is sealed therein and extends downwardly to the bottom end of the valve providing a conduit from the recess to the sealing pocket.

A small quantity of mercury 9 is arranged in the pocket formed between the bottom end of the inlet tube 3 and the casing 1 and seals the bottom end of the valve 6 andtube 8 secured thereto. The valve 6 is supported slightly above the flange 4 and with its inner tapered surface just clear of the tapered outer surface of the inlet tube 3 and the mercury fiow s around the free edge of the valve in a perfect seal which will effectively hold the pressure of the normal hydrostatic column of fluid thereabove.

A collar 10 secured in the top of the cylinder 1 is threaded on to the stand pipe 11 which preferably projects a short distance below the collar and forms an annular recess 12 which prevents the escape of the mercury from the foot. valve while being handled prior to its being placed in the tank.

A spider 13 is threaded into the inner end of the pipe 11 and supports a check valve 14 the stem 15 of which extends below the spider and 94 is provided with a stop block 16 Which forms, a limit stop for the upward movement of the valve 6. This stop valve checks the back flow of fluid in the stand pipe immediately on the cessation of operation of the pump connected with the 95 stand pipe.

It has been found in the use of mercury sealed valves previously proposed that abnormal condij tions arising in the stand pipe above the foot valve and creating pressures greater than that of the normalhydrostatic column caused the mer-v cury to be driven from the sealing pocket up-- wardly between the inlet tube and the tubular valve and as the inner wall of such valves extended above the top of the inlet tube the mercury flowed into the tank and the valve became useless.

In the construction of the valve herein shown the mercury when forced upwardly between the valve 6 and tube 3 and the tube 8 flows into the enlargement 7 of the valve where it is intercepted and permits the escape of the excess pressure, the mercury then flowing back to the sealing pocket, thus enabling the continual reestablishment of the seal to support the fluid column for which the valve is designed.

The result of this means for intercepting the mercury and returning it to the sealing pocket is that while any excess pressure exists in the column above the foot valve it will work its way between the valve 6 and tube 3 escaping to the tank without detrimentally affecting the mercury seal.

The valve 14 is provided to check the flow of the fluid due to excess pressure thereby relieving the mercury seal from undue disturbance and allowing the excess pressure to equalize gradually as the liquid filters through to the lower chamber.

A suitable screen 17 is arranged at the bottom of the cylinder 1 to arrest particles of grit or other foreign matter and the clearance between the valve 6 and metal tube 3 is such that any foreign particles passing the screen will not lodge between said valve and tube but will carry freely therethrough.

The device is extremely simple and inexpensive to build as no close fitting surfaces are required and it is found that it will eifectively retain the lightest fluids indefinitely and it operates auto matically and without loss of fluid.

In the form of the invention shown the inlet tube and valve are shown tapered but it must be understood that they may be of cylindrical or other shape without departing from the spirit of the invention.

What I claim as my invention is:-

1. A foot valve having a tubular inlet surrounded by a sealing pocket, a sealing fluid in said pocket, 2. displaceable tubular valving member enclosing said tubular inlet and movable into and out of sealing relation with said tubular inlet and said sealing fluid, said valve being recessed on the inner side adjacent the upper end thereof to receive upwardly-displaced sealing fluid, and a conduit connecting said valve recess to said pocket.

2. A foot valve having a tubular inlet surrounded by a sealing pocket, a sealing fluid in said pocket, a tubular valve enclosing said tubular inlet having its bottom edge sealed in said sealing fluid and having an enlarged upper end forming a recess surrounding the upper end of the inlet tube with its bottom normally below the top of the inlet tube, and a tube opening into said recess and extending down to the bottom of the valve.

3. A foot valve having a tubular inlet surrounded by a sealing pocket, a sealing fluid in said pocket, a tubular valve enclosing said tubular inlet having its bottom edge sealed in said sealing fluid and having an enlarged closed upper end enclosing the upper end of said inlet and having its bottom encircling said inlet tube nor- -mally below its upper extremity, and a tube opening into said enlarged upper end and extending downwardly and entering said fluid seal. 4. A foot valve comprising a cylindrical casing, an inlet tube extending upwardly within said casing and forming an annular sealing pocket, a mercury seal in said pocket, a ring secured in the top of said casing, a stand pipe secured in and extending below said ring and forming a seal, a tubular valve enclosing said inlet tube, and means forming part of said valve surrounding the upper end of said inlet tube adapted to intercept a sealing fluid and direct it back to said sealing pocket.

5. A valve comprising a jacket, a frusto-conically shaped inlet pipe rising from the bottom of the jacket and extending upwardly therewithin, frusto-conically shaped bell receiving the pipe and normally seated thereon, a closed overflow head carried by the upper end of the bell and enclosing the upper end of the inlet pipe, said upper end of the inlet pipe projecting within the overflow head above the bottom thereof in the seated position of the bell, a liquid contained in the lower end of the jacket, said liquid having a relatively high specific gravity and said bell having the lower end thereof normally immersed in the liquid, and a passage extending from the lower part of the head and having the lower end thereof normally immersed in the liquid.

6. A valve comprising a jacket having the upper end thereof provided with an outlet opening, a frusto-conically shaped inlet pipe rising centrally within the jacket from the bottom thereof, a liquid having a relatively high specific gravity contained in the lower end of the jacket, a frustoconically shaped bell surrounding and normally seated on the inlet pipe and having the lower end thereof in the seated position of the bell immersed in the liquid and the upper end thereof stopping short of the upper end of the inlet pipe, a closed overflow head carried by the upper end of the bell and enclosing the upper end of the inlet pipe, a pipe leading from the bottom of the head and having the lower end thereof immersed in the liquid in the seated position of the bell, and means for limiting the upward travel of the head.

'7. A foot valve having a tubular inlet surrounded by a sealing pocket, a sealing fluid in said pocket, a tubular valving member enclosing said tubular inlet and movable into and out of sealing relation with said tubular inlet and said sealing fluid, and means forming a cavity to temporarily receive sealing fluid forced upwardly between the'inlet and valve, said cavity having a tubular connection with the sealing pocket.

8. A foot valve having a tubular inlet surrounded by a sealing pocket, said pocket having a sealing fluid therein, a valve member surrounding said tubular inlet in spaced relation therewith and sealingly engaged at the bottom by said sealing fluid, said fluid being adapted to rise excessively in said space under abnormal pressure conditions, and means normally disposed below the inlet top for temporarily receiving the excessive displacement of said fluid during the abnormal pressure condition to prevent same from overflowing the top of said tubular inlet, said receiving means having return communication with said sealing pocket independent of said space.

WILLIAM H. D. BROUSE.

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