US3047011A - Vacuum responsive servo flow control valve - Google Patents

Description

July 31, 1962 G. w. WRIGHT ETAL 3,047,011

VACUUM RESPONSIVE SERVO FLOW CONTROL VALVE Original Filed June 13, 1956 INVENTOR.

I WRIGHT y BURDETTE W. F055 ATTORNEY Claims. or. 137-4921 This invention relates to a control valve for booster pumping system for dispensing fuels, particularly such fuels as are prone to vaporize under high ambient temperatures and/or vacuum to produce vapor lock in the system. This application is a division of our prior application Serial Number S9l,l88 filed June 13, 1956, entitled Booster Pumping System.

Vapon'zation of fuels, such as gasolines, in fuel dispensing systems such as are used to fuel automobiles in the usual automobile filling stations has, in recent years, created problems in the dispensing of such fuels. Briefly stated, the vapor pressures of such fuels are being reduced and this results in the inability of the usual motor pump type of filling station dispenser, which is usually disposed at some distance from the tank, to lift the fuel from the storage tank, draw it through the lateral suction conduits to the pump in the dispenser and thereafter deliver the fuel under pressure to the vehicle tank. The fuels vaporize in the pipe when the suction is applied by the pump and either the pump fails to prime or its delivery is greatly reduced. These difficulties are usually experienced in hot weather when the pumps, lines and even the gasoline in the tanks becomes hot. Gasoline temperatures of 100 degrees Fahrenheit and higher are experienced and it has occurred several times that only one or two filling stations in a relatively large city were able to dispense any gasoline at all on hot days.

It is an object of the invention to provide a control valve in advance of each dispenser pump for preventing the flow of fuel to the dispenser when the dispenser is not delivering fuel even though the dispenser pump may be running.

Yet another object of the invention is to provide a control valve which is responsive to the vacuum created by the associated dispenser pump to control the admission of fuel to such dispenser pump.

Still another object is to provide a control valve for use at the inlet of each dispenser which throttles the rate of flow of fuel to the pump of such dispenser substantially in proportion to the rate of flow of the fuel being delivered by such dispenser.

Another object of the invention is to provide, for a system of the type described, a control valve which will prevent fuel from being drawn from the nozzle of an otherwise inoperative dispenser while the remote pump is operating.

These and other objects will become apparent from a study of this specification and the drawings which are attached hereto, made a part hereof and in which- FIGURE 1 is an elevation in section of the control valve mechanism which is used to control the flow of liquid to the individual dispensers.

FIGURE 2 is an elevation showing a system in which the source of supply is an elevated tank or pressure tank.

Control Valve (FIGURE 1) It will be understood that if liquid were supplied under pressure to the dispensers 301 when the pump 29 is inoperative or when the nozzle valve is closed or nearly closed even with pump 29 operating, liquid would be forced out the vent pipe which is usually provided on the sep- 3,947,011 Patented July 31, 19%2 arator and would be discharged exteriorly of the dispenser so as to create a fire hazard as Well as to result in the wastage of a fairly expensive fluid.

The valve 25 prevents such discharge as will be seen from FIGURE 1 in which the body 79 and a diaphragm 81 define a first chamber 83 which communicates with the branch pipe 26 while this diaphragm and a cap 84 define a second chamber 85 which communicates with the first chamber through a restricted pressure balancing orifice 87.

The body and a second diaphragm 89 define a vacuum chamber 91 which communicates with the suction pipe 27 while an atmospheric chamber 93, which is ventedthrough a restricted orifice 95, is defined by diaphragm 89 and a cap 96.

A port or passage 97 connects the chambers 83 and 91 in communication and is adapted to be opened, and closed or throttled by a valve 99 which is carried by the, diaphragm 81. The valve is closed by movement of diaphragm 81 toward the port 97 and thus closes with the flow from the inlet chamber 83 to the outlet chamber 91.

The valve has a central port or passage 191 which connects the chambers 85 and 91 in communication and this port is opened, closed or throttled by a valve 103 which is disposed in chamber 85 and is supported on a stem 105 which runs through passage 101 into chamber 91 where it is fixed to the diaphragm 89. The stem 105, as shown in FIGURE 1, has an upwardly converging tapered flow metering section or element 105 disposed immediately above the valve 193. The metering element coacts with the port 101 to gradually restrict or increase the flow of fluid therethrough when the valve 103 is open and it is moved relative to the valve 99. The taper is longer and included angle of the taper of this element is less than that of valve 103 and the maximum diameter of the element is substantially the same as the minimum diameter of the valve 103 so that once the valve 1% is opened, the effective area of the port 191 and therefore, flow through port are governed by the axial position of the element 1G5 with respect to that of the port. Valve 103 and port 161 tend to close both when diaphragm 89 moves away from port 191 or when valve 99 moves in an opening direction.

A spring 1% in chamber 85 acts on the diaphragm 81 in It will thus be seen that when no liquid under pressure .is applied to chamber 83, the spring 106 will hold valve 99 closed and that when no vacuum is applied to chamber 91, the spring 167 will hold valve 103 closed. Spring 107 acting through stem 16-5 and valve 103, also helps to hold valve 99 closed. I

So long as valve 1% remains closed, the valve 99 will remain closed even though liquid under pressure is applied to chamber 83 under pressure because the pressures in chambers 83 and 85 will be balanced through the orifice 87 and there will be no force applied to the diaphragm in a direction to overcome either spring 106 or 107.

No suction will be created in chamber 91, even with the associated pump 29 in operation, so long as the nozzle remains closed because under such conditions the by-pass valve which is always provided for pump 29 is wide open and liquid is merely circulated from the pressure side of the pump to its suction side. The valve 103 will therefore remain closed.

As soon as the nozzle valve 69 is opened even slightly, a slight vacuum is produced in chamber 91 and when the vacuum reaches a value high enough to enable the diaphragm 89 to overcome spring 107, valve 103 will open proportionately.

This then permits liquid to flow from chamber $5 through port 101 to chamber 91. When the fiow of liquid through the valve .exceeds the flow of liquid into chamber 85 through the orifice 87, the pressure in the chamber will drop below that in chamber 33 and when the diflerential pressure on the diaphragm is sufficient to overcome spring 10 5, the valve 99 will open to permit liquid to flow directly from chamber 83 to chamber 91 through port 97.

When this occurs, the movement of valve 99 relative to metering. element 105' tends to close the port 101 and more nearly equalize the pressures. in the chambers 83 and 85 so that the valve 99 will stop. Similarly, the

pressure in chamber 91 tends to increase slightly which also tends to move valve 103 and metering element 105' in a direction to cause 105' to restrict the port 101, and thus further assists in more nearly equalizing the difierential across the diaphragm 81. Thus the valves quickly reach a condition of equilibrium in which the opening of valve 99 is proportional to the rate of flow of the liquid being dispensed through the nozzle valve.

Should the nozzle valve be fully opened, a greater vacuum will be produced in chamber 91 and the valve 103 will open to a greater extent. This results in a Wider opening of the valve 99 before equilibrium is established so that again the rate of flow of liquid through valve 99 is proportional to the flow through the nozzle.

The orifice'95 resists the rapid flow of air to and from chamber 93 and thus exerts a damping effect to reduce ove-rtravel of the valve 103 in response to sudden changes of pressure in chamber 91 and, in turn, the valve 103 reduces overtravel of the valve 99 to reduce hunting action and to promote rapid attainment of the equilibrium condition. Should the nozzle valve be closed or should the pump be stopped, the vacuum disappears entirely from chamber 91 and valve 103 will immediately be closed by spring 107. As soon as this occurs, the pressures in chambers 83 and 85 Will become equalized through the orifice 87 and spring 106 will close valve 99 so that no liquid can flow to the dispenser even though chamber 83 is supplied With fluid under pressure from branch pipe 26. Valve 103 remains closed as valve 99 closes.

It will thus be seen that the flow from branch 26 is held proportional to the flow from the nozzle and the dispenser is protected from excessive pressures which would tend to make the nozzle valve chatter and become unmanageable. Since all fiow to the dispenser is stopped when no liquid is being drawn from it, the m'r release will not flood. Similarly, since the valve 99 is closed when the associated pump 29 is not operative, no liquid can be drawn from the inoperative pedestal and the air separator will not flood.

Illustrative System (FIGURE 2) FIGURE 2 illustrates a system in which a motor pump type of dispenser 301 is connected to a liquid supply line 303 which isconnected at its other end to an above ground supply tank 305 through a control valve 25.

When a single dispenser is used with the line 303, the valve 25 is preferably located adjacent the tank 305 so that it will protect the line as well as the dispenser against leakage.

If a number of dispensers are used on the line, a valve is used adjacent each dispenser in the branch 26 to such in the case in which valve 25 is disposed adjacent the tank, until line 303 is evacuated by the dispenser pump,

no liquid can flow through the valve 25 to line 303 and be lost through any leaks or breaks therein. in line 303 are substantial, the air flowing in through them may be sufiicient to prevent the establishment of the vacuum required to open the valve and in such'case the system will be inoperative'until the leaks are repaired.

In the case of the use of valves 25 in parallel as shown in FIGURE 2, by the dashed lines, the operation of any pump will create the vacuum necessary to openthe valve 25 adjacent the pump. I

it is obvious that various changes may be made in the form, structure and arrangement of parts of the specific embodiments of the invention disclosed herein for purposes of illustration, without departing from the spirit of the invention. Accordingly, applicant does not desire to be limited to such specific embodiments but desires protection falling fairly within the scope of the appended claims.

We claim:

l. A control valve comprising a body, first and second displacement means defining with said body an inlet and an outlet chamber, said body defining a first port connecting said chambers, a control valve for said first port connected for operation by said first displacement means, yieldable means for urging said control valve toward said port to close it, means cooperating with said first displacement means for form a third chamber, means defining an orifice connecting said third chamber in communication with said inlet chamber, means defining a second port connecting said thirdchamber in communi-.

cation with said outlet chamber, second valve means mounted to control said second port and connected for operation by said second displacement means in a direction to open said second port when a vacuum is applied to said outlet chamber, yieldable means for urging said second valve means toward said second port, ,said means defining said second port being connected for movement by said first displacement means and relative tosaid second valve means in a port closing direction, as'said control valve opens, said second valve means and second port defining means being constructed so as to gradually increase and decrease the efiective area of said second port upon relative port opening and closing movement thereof, said first displacement means being movable in response to the opening of said second valve means to open said control valve to the degree necessary to establish equilibrium between the respective total forces acting on said first and second displacement means.

2. The structure defined by claim 1 which includes means for damping the movement of said second displacement means.

3. A control valve comprising a body, first and second displacement means defining with said body an inlet and an outlet chamber, said body defining a first portconnecting said chambers, a poppet type of control valve for said first portconnected for operation by said first displacement means to open and close said first port,

' yieldable means for urging said control valve toward said port to close it, means cooperating with said first displacement means to form a third chamber, means defining an orifice connecting said third chamber in communication with said inlet chamber, means defining a passage through said control valve, said passage having a second port, connecting said third chamber in communication with said outlet chamber, second valve means comprising a pilot valve constructed with a short tapered portion having a large included angle and. a metering element constructed with a relatively long tapered portion having a relatively small included angle, disposed to open and close said passage and to increase and decrease the efiective area of said second port respectively and having a stem connected for operation by said second displacement means in a direction to open said passage when a vacuum is applied to said outlet chamber, yieldable means for urging saidsecond valve means toward said second port, said control valve, when it is moved in an opening If the leaks direction by said first displacement means, serving to move said second port relative to said second valve means in a direction to reduce the effective area of said second port, so that the effective area of the second port is gradually increased and decreased, upon relative movement of said control valve and said second valve means, to the degree necessary to establish equilibrium between the forces acting on said first and second displacement means.

4. The structure defined by claim 3 which includes a dash pot connected for damping the movements of said second valve means.

5. The structure defined by claim 3 wherein said dash pot includes a movable control means comprising said second displacement means.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Italy Feb. 20, 1932 France Sept. 21, 1943

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