US2273217A - Method of and apparatus for controlling flow - Google Patents

Description

1942- R. w. PRESSEY METHOD OF APPARATUS FOR CONTROLLING FLOW Filed March 17, 1939 INVENTOR. BY [Mg WPresseg :3 ATLIORN Patented Feb. 17, 1942 UNITED STATESPATENT OFFICE METHOD OF AND APPARATUS FOR, C NTROLLING FLOW Ralph W. Pressey, Newtown Square, Pa.

Application March 17, 1939, Serial No. 262,372

8 Claims. Cl. 237-9) My invention is a method of and apparatus for controlling flow which is responsive to slight variations in the pressure of a fluid, and particularly of a condensible vapor such as steam, flowing through a conduit. It is primarily designed to maintain the flow at a constant pressure within very close tolerances by apparatus which is simple, inexpensive and free from parts likely to deteriorate or get out of order.

My improved flow controller is further designed to be immediately responsive to an increase in pressures and'more slowly responsive to a decrease in pressure, and it includes a valve which is immediately moved toward closing position upon any rise in pressure and which is opened slowly upon a drop in pressure.

My improved flow controller is particularly applicable to the control of low pressure steam heating systems where it is desired to maintain an adjustabl'y constant low pressure of steam on radiators notwithstanding changes in the radiating circuit or changes in the high pressure steam supply line. My improvements may, however, be applied to the control of flows of gaseous or liquid fluids at high or low pressure.

In a preferred embodiment of my invention, variations in pressure of vapor flowing in a conduit act upon condensate from such vapor to vary the relative quantities of condensate in communicating vessels. The consequent variations in liquid head in one of the vessels effect actuation of a valve controlling the vapor conduit. One of the vessels preferably comprises a pipe section depending from a T-fitting of the down-flow side of the vapor conduit and has its bottom closed or plugged so as to form a receiver or reservoir in which condensate from the vapor system collects to a depth regulated by a trapped overflow line. The other vessel preferably consists of a receptable suspended from a valve operating arm and communicating with the reservoir through a flexible tube terminating in a nozzle projecting into the receptacle and preferably having an end port and a side port spaced from one, another and ofdifferent areas.

The characteristic features and advantages of my improvements will further appear from the following description and the accompanying drawing in illustration thereof.

In the drawing, Fig. 1 is a side elevation of a flow controll r embodying my improvements; Fig. 2 is an enlarged fragmentary vertical sectional View of the valve-operating receptacle; Fig. 3 is an enlarged fragmentary vertical sectional view of the air valve of the valve-operating receptacle;

- low pressure conduit 2 through a valve 3 having a valve stem 4 vertically reciprocable, to open and close the valve, by an arm 5 fulcrumed on the bearing 6 and guided by the guides l; the valve stem being normally biased toward open position by a counterweight 5.

The low pressure conduit section 2 includes a T-fitting 8 having one of its ports communicating with a distribution line 9 and the other of its ports communicating with a depending pipe sec- 1 tion [0 having a closed bottom forming a con densate receiver or reservoir I 0' in the lower portion thereof. A valved overflow tube H communicates with the pipe section Hi to limit the depth of condensate in the reservoir l0 and discharges to waste through a sealed or float-controlled trap I2 which, while maintaining the pressure in the system, permits the escape of excess condensate from the pipe section H] but prevents the escape of vapor.

The lower portion of the reservoir Ii! communicates, through the valved fitting l3 and flexible tube I4, with a nozzle [5 adjustably mounted in the bottom of the receptacle I 6 which is suspended by a tension member I! from the valve operating arm 5. The nozzle 15 has a lateral port l8 within the receptacle l6 adjacent to the bottom thereof and an end port I 9 of larger area than the port I8.

A gauge glass 20 is mounted on the receptacle 7 16 so as to communicate therewith near the top and bottom thereof. An air escape valve 2! is mounted on top of the receptacle and has a port 22 controlled by a float valve 23 by which escape of air from the receptacle is permitted but the escape of liquid is prevented.

In the operation of the device, condensate from vapor flowing through the'conduit system collects in the reservoir 10'. With the valve 3 positioned to give a desired pressure in the conduit 2, the controller parts are so adjusted that the vapor pressure will force sufiicient condensate from the reservoir I0 into the receptacle It to weight the latter sufficiently to maintain the valve in normal position against the bias imparted by the counter-balance 5 on the valve arm 5; the nozzle l5 being so adjusted that its mouth 59 is substantially coincident with the normal level of the condensate in the receptacle Hi. If further condensate accumulates while the pressure in the conduit 2 is constant, such excess escapes through the pipe H and trap l2 so that the quantity of condensate in the reservoir and receptacle I6 is substantially constant so long as the pressure in the conduit 2 is constant. Should the vapor pressure in the conduit 2 rise, condensate is forced from the reservoir [0 into the receptacle 16, thereby increasing the weight of the latter and pulling the valve stem 4 toward closing position. The air displaced from the receptacle l6 by the additional condensate escapes through the valve port 22, but should the excess pressure in the conduit 2 be so great as to entirely fill the receptacle I6 and the valve body 2|, the float valve 23 closes the port 22 and prevents the overflow of liquid. As soon as the pressure in the conduit 2 drops to normal, condensate flows from the receptacle l6, through both ports 19 and 18 of the nozzle 15, back to the reservoir Hi, thereby rapidly lightening the vessel l6 until the level of liquid therein is back to the original setting. If the pressure in the conduit 2 falls below normal, the liquid in the receptacle l6 escapes slowly through the port I8 back to the reservoir I0, thereby permitting the counterweight on the lever 5 to slowly lift the valve stem 4 and open the valve to permit the ingress of additional steam. The condensate from the system will quickly make up any loss of condensate resulting from its escape through the discharge pipe H as a result of the return of condensate from the vessel E6 to the reservoir l0.

Instead of making the valve-control receptacle cylindrical it may be made of irregular cross sec tion, such for instance as the spherical or spheroidal receptacle shown in Fig. 4. In the construction illustrated in Fig. 4, the spheroidal receptacle lBa is supplied with condensate from the reservoir l0 through the nozzle 1501, having the ports l8a and I911. The port l9a is normally positioned slightly below the center line of the vessel and there is therefore an equatorial zone in the receptacle in which very slight changes in surface level will effect a substantial change in the weight of the vessels contents and hence of the force applied to the valve arm 5. Increased sensitiveness of the apparatus to variations of vapor pressure from normal may be thereby secured without abnormally weighting the valve arm 5 during normal operation.

Having described my invention, I claim:

1. A flow controller comprising a valve conduit, a liquid reservoir, means communicating with and supplied with fluid from said conduit, a vessel operatively connected with and controlling the valve of said conduit and a flexible tube connecting said reservoir and vessel, said tube having a section projecting into said vessel and provided with an end port and a side port at different distances from the bottom of said vessel to rapidly fill and more slowly drain said vessel.

2. A flow controller comprising a valved conduit, a vessel operatively connected with and controlling the valve of said conduit, means for supplying liquid to said vessel from said conduit in response to a rise in pressure in said conduit and for draining said vessel in response to a pressure drop in said conduit, said means connecting said conduit and vessel and forming a plurality of ports communicating with said vessel and one of which is of larger area and at a greater distance from the bottom of the vessel than the other port so that the vessel may be filled with liquid above the upper port through both of said ports more rapidly than. it can be drained below the upper port through the lower port alone.

3. A method of controlling the flow of a condensible vapor which comprises condensing a portion of such vapor in a receiver, expelling from said receiver variable portions of the condensate by the pressure on the condensate of uncondensed Vapor and controlling the supply of vapor by variations in the weight of the expelled portions of condensate which vary the elevation of the expelled condensate, relatively to the point of expulsion thereof from the receiver, inversely to the weight of condensate expelled so that the greater the weight of the condensate portions expelled the lower the elevation thereof falls.

4. In a heating system including a high pressure steam supply line and a low pressure radiating circuit with which said line constantly communicates, means for maintaining the pressure of steam in the radiating circuit substantially constant and comprising a condensate collector means constantly communicating with the radiating circuit, means for maintaining in the collector a substantially constant quantity of condensate so long as the pressure in the radiating circuit is substantially constant, a reducing valve mechanism including a valve between the high pressure line and low pressure circuit, a hollow vessel suspended from said mechanism for operating said valve, and a conduit through which condensate flows back and forth between the interior of said vessel and collector means with variations in the pressure in said radiating circuit and thereby varying the weight suspended from said valve mechanism.

5. The combination with a conduit and condensate-receiver-means communicating therewith, of weight-operable valve mechanism con trolling flow between said conduit and means, a liquid container supported by said valve mechanism in weight-operating relation thereto, and a tube connecting said container and means and through which tube condensate flows backward and forward between said container and means to vary the weight of the contents of said container and the stress thereby imparted to the valve mechanism with changes in pressure on condensate in said means.

6. A flow controller comprising a conduit including a valve mechanism, valve-operating means operatively connected with said valve mechanism and including a liquid container having a plurality of ports for supplying liquid thereto and draining liquid therefrom, one of said ports being higher than the other so that the container may be filled with liquid above the upper port more rapidly than it can be drained below such port, and condensate receiver means connected with said conduit and communicating through said ports with said container.

7. A flow controller comprising a conduit including valve mechanism, valve-operating means operatively connected with said valve mechanism and including a liquid container having an airescape port, a float-operable valve in said container for closing said air-escape port when the container is full, and condensate-receiver means communicating with said conduit and container.

8. The combination with a conduit and condensate-receiver means communicating therewith, of weight-operable valve mechanism con: trolling flow between said conduit and means, a liquid container suspended from said valve mechanism and imparting stress to the valve mechanism proportional to the weight of the contents of said container, an air-escape port in said container, a float-operable valve controlling said port, said container having therein means forming a plurality of ports for supplying liquid thereto and draining liquid therefrom, one of said ports being below and smaller than the other so that said container may be filled more rapidly than it can be drained, a flexible tube connecting said means with said ports, and a trapped discharge pipe communicating with said means above the connection of said flexible tube therewith.

RALPH W. PRESSEY.

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