US2387225A - Modulating valve - Google Patents

Description

Oct. 23, 1945. 'H L BE L Y 2,387,225

MODULATING VALVE" Filed Nov. 30/ 1942 Patented Oct. 23, 1945 UNITED STATE S PATENT OFFICE Electrimatic Corporation,

Illinois a corporation of Application November 30, 1942, Serial No. 467,299

9 Claims.

This invention relates to'a modulating valve, and more particularly to an improved valve for regulating fluid flow.

One feature of this invention is that it provide an improved modulating valve; another feature of this invention is that it'provides structure wherein a diaphragm may be used as the actuating member for the main valve; still another feature of this invention is that the pilot valve action is very stable; yet another feature of this invention is thatthe effect of pressure variations of the claimed herewith is primarily connected with this latter type of valve, conventionally called a modulating valve.

In order to have modulating action, the position of the main valve must in some-way affect the control mechanism or pilot valve. That has heretofore been accomplished commercially by having the seat or orifice with which the pilot valve cooperates carried by the main valve, or by mechanism associated with the main valve. This arrangement is not well adapted to use with diaphragm actuating means, however, and presents a number of problems in construction and operais sealed to the main valve member II, by any appropriate means, here shown as a gasket 25, and a threaded cap 26. The casting 23 carries still another casting 21, all three of these castings cooperating to form the valve body as a whole.

The valve body is surmounted by the actuating portion of a control arrangement. This is here shown as a conventional arrangement intended to be operated by fluid pressure, as fluid from a control thermostat. The control fluid is admitted through the pipe 28, to the housing 29, where its pressure is exerted on the top of member 30, in opposition to a spring 3|, so that the position of the member 30 and of the rod 32 fastened to it are a function of the pressure of the control tion. The invention disclosed herewith enables modulating action even though the orifice with which the pilot valve cooperates is fixedly mounted in the valve body. This is accomplished by having the control means arranged to move the pilot valve in one direction against the force of a spring, and arranging the spring so that the main valve position aifects its tension or force.

In the particular embodiment of my invention disclosed herewith, the valve is shown as comprising a main body casting l0 having an inlet II and an outlet l2, separated by a partition I 3 having a main valve or orifice l4 therethrough. The oriflce I4 is surrounded by a bead It, with which packing i8 cooperates, this being carried by the main valve member H. The members I8 and 19 are merely parts of a spider serving as a guide for the rod 20 carried by the main valve member. Plug 2| and screw 22 are merely drainage means.

The upper part of the main casting I0 i enclosed by another casting 23, these two castings being bolted or otherwise clamped together about the outer edge of a diaphragm actuating member 24, which may be of leather or similar flexible impervious material. The center of this diaphragm fluid. A sealing arrangement is provided, in conventional manner, by a Sylphon or sealing bellows 33.

Returning now to the valve body, it will be seen that an actuating chamber 34 is provided above the diaphragm 24, and space provided around the diaphragm on its under side so that it is open to pressure in the inlet of the valve. Thus, pressure in the chamber 34 tends to move the diaphragm and main valve ll downwardly, and the space beneath the diaphragm, by exposing its underside to inlet pressure, provides a force opposing pressure in the chamber 34.

immediately above the actuating chamber 34, but sealed from it, is a pilot valve chamber 35. Thebody of the valve is drilled with various passageways as shown. Passageways 36 and 31 lead to a restricted passageway 38 openlng into the actuating chamber 34; and from this point passageways 39 and 40 communicate, throughan orifice 4|, withthe chamber 35, communication being provided from this chamber to the valve outlet by the passageways 42 and 43. Since the pressure in the actuating chamber 34 is what determines the position of the main valve, passageways .38 and 3'! form what may be termed the inlet passageway, this Joining the restricted passageway into the chamber 34 and the outlet Dassageway, thev latter comprising a flow path inflow. This comprises a pilot valve 45 cooperating with an annular bead 4B, surrounding the orifice 4|. The pilot valve is carried by a longitudinally movable rod member 41, which extends down into the actuating chamber; anda rod member 48 is adapted to force the pilot valve down away from its seat when the pressure of the control fluid increases sufficiently.

It will be noted that the main orifice andvalve member, the rod members 41 and 48, and the pilot valve and its orifice, are all coaxial.

Both of the rod members 41 and are sealed so that there can be no movement of fluid through the openings in which these rod members move, this being here shown as accomplished by sealing bellows 49 and 50. Fluid pressure in the chamber 34, in the particular arrangement of parts shown here, tends to move the rod member 41 up, while fluid pressure in andabove the orifice 4| tends to move the rod member 48 up, but the valve member 45 down. Since these fluid pressures are the same and are a function of the inlet pressure of the fluid being con- I trolled, proper design and proportions of the parts can eil'ect a balance of forces such that operation of the pilot mechanism is independent of fluid pressure in the inlet of the valve. Since the pressure on both sealing bellows is such that force exerted through the rod 48 and the upward restoring forceprovided by the spring SI, and when this restoring force has reached .the proper value, the pilot valve 45 will have been moved back up to a position where the outlet flow bears the proper relation to the inlet flow, whereupon the partswill become stabilized and the main valve will remain in that position. Any slight increase or decrease in pressure of the control fluid will result in a new position of the main valve, these bearing a predetermined relationship which can. be worked out in advance and which is independent of the pressure of the fluid being conit will force upward while that on the valve member is down, the effective diameters oi the sealing bellows (thediameters or their inner convolutions) are so chosen that their two areas, when added together, are equal to the area within the bead 4!, the area over which fluid pressure is effective on the valve member 4!. These areas should always hear a relation such that the area within the bead 48 is equal to the algebraic sum of the effective areas of the sealing bellows. That is, if the pressure on both bellows is effective in a direction opposed to that on the pilot valve, their areas would be added with a plus sign, while it one is in the opposite direction, its area would be subtracted from that of the other bellows to determine the proper area for the head 46. In any event, of course, all portions of the outlet passageway must be larger than the narrowest portion of the inlet passageway adjacent to plug 44, so that fluid can always be removed from the actuating chamber 34 faster than the inlet passageway can supply it.

The main valve member l1 carries within it a fairly heavy spring II, the upper end of this spring carrying a pressure member 52. which makes point engagement with the lower end of the rod member 41. when the parts are in the position shown, therefore, the pressures above and below the actuating diaphragm 24 are substantially balanced (since i'ull inlet pressure exists on both sides), and the force of the sprin 5i and the weight oi the valve I! keep it closed. when the control arrangement reacts to a demand for fluid flow. however. the pilot valve is V pushed downwardly by the rod member 48. and

- chamber), the diaphragm moves upwardly, carrying the. main valve member with it, and opening the main flow passageway.- Any upward movement of the main valve member, however, raises the lower end of the spring BI and 'thus increases the force of its upward pressure on the pilot valve 45. The position of the pilot valve 45 is thus a function of thedownward control trolled.

This arrangement provides a particularly good and stable modulating valve structure, a retarding or dash pot action being provided by the slow movement of liquid in and out of the actuating chamber 34 because oi. the restricted nature of the passageway 38. While this valve may be made in any desired size, it provides a particularly important improvement in operation in large sized valves. 1

While I have described and shown certain embodiments of my invention, it is to beunderstood that it is capable oi many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope or the invention as disclosed in the appended claims.

' I'claim:

l. A modulating valve 01' the character described adapted to control the flow 01' fluid under pressure, including: a valve body having an inlet and an outlet and a partition separating them, the partition having a main flow opening therethrough; a main valve member arranged to control flow through the opening; a control chamber; a diaphragm actuating member having one side subject to the pressure in the control chamber and its other side subject to inlet pressure;

means connecting the actuating member and the 48 for venting pressure in the chamber; control means constructed and arranged so as to vary the flow thorugh one of said passageways in a manner to vary. the pressure in said control chamber and cause movement of the actuating member; actuating means for the control means including yieldable force applying means opera-j tive thereon; and yielding means operatively connected to the main valve member and to the control means, the connection being such that movement of the'main valve member toward and away from said main flow opening results in the application oi a force through said connection in a direction to oppose the force applied by the actuating means to affect flow through the controlled passageway in a manner tending to ofiset the initial variation in the pressure in the control chamber.

2. A modulating valve of the character de-,

scribed adapted to control the flow of fluid under pressure, including: a valve body having an inlet its other side subject to inlet pressure; means connecting the actuating member and the valve.

member; a passageway connecting the control chamber to the inlet; a second passageway for venting pressure in the control chamber; an orifice means forming part of one of the passageways, said orifice means being fixedly positioned;

a pilot valve for controlling flow through said orifice means so as to vary the pressure in the control chamber; control means affecting the position of said pilot valve, said control means including yieldable force applying means operative on the pilot valve to actuate it in one direction; and yielding means operatively connecting the main valve and the pilot valve, the connection being such that initial movement of the pilot valve in a certain direction causes movement of the main valve in a direction such that forces are developed in and transmitted through the connection opposing movement of the pilot valve in the initial direction, whereby movement of the main valve toward and away from the main flow opening affects fiow through the passageway having said pilot valve controlled orifice means therein.

3. A modulating valve of the character described adapted to control the flow of fluid under pressure, including: a valve body having an inlet and an outlet and a partition separating them,

the partition having a main fiow opening therethrough; a main valve member arranged to concontrol chamber and cause movement of the actuating member; control means for moving the pilot valve, said control means including yieldable force applying means operative on the pilot valve to actuate it in one direction; spring means providing a force opposing such movement; and means providing an oprative connection between the main valve and the spring, the connection being such that movement of the main valve toward and away from the main flow opening varies said 4. Apparatus of the character claimed in claim 3, wherein the main valve and pilot valve are coaxial and said spring has one end carried by the main valve. 3

5. Apparatus of the character claimed in claim 1, wherein the connection between the control chamber and at least one of the passageways is restricted, whereby movement of the main valve in at least one direction is retarded.

6. A modulating valve of the character described adapted to control the fiow of fluid under pressure, including: a valve body having an inlet and an outlet and a partition separating them, the partition having a main flow opening therethrough; a main valve member arranged to control flow through the ripening; a control chamher; a movable actuating member having one side subject to the pressure in the control cham-- her and its other side subject to inlet pressure; means connecting the actuating member and the valve member; a passageway connected to the inlet; a second passageway connected to the outlet, said passageways joining each other; a restricted communication between the control her;

chamber and the point of juncture of said passageways; an orifice means forming part of one of the passageways, said orifice means being fixedly positioned; a pilot valve for controlling fiow through said orifice meansso as to vary the pressure in said control chamber and cause movement of the actuating member; control means afiecting the position of said pilot valve, said control means including yieldable force applying means operative on the pilot valve to actuate it in one direction; and yielding means operatively connecting the main valve and the pilot valve, the connection being such that movement of the main valve results in the application of a force through said connection in a direction to oppose the movement of said pilot valve which caused the movement of the main valve, the position oi the pilot valve being a function of both of the last mentioned means.

" "I. A modulating valve of the character described adapted to control the flow of fiuid under pressure, including: a valve body having an inlet and an outlet and a partition separating them: the partition having a main flow opening therethrough; a main valve member arranged to control flow through the opening; a control chamber; a movable actuating member having one side subject to the pressure in the control chamber and its other side subject to inlet pressure; means connecting the actuating member and the valve member; a passageway connectingthe control chamber to the inlet; a second passageway for venting pressure in the control chamber; a pilot therearound, flow or fluid through this orifice afiecting the pressure in the control chamber; a-

pilot valve for controlling flow through said orifice so as to vary the pressure in the control chamcontrol means comprising a control rod member passin through said orifice and adapted to engage said pilot valve to affect the position thereof, said control means including yieldable force applying means operative on the pilot valve to actuate it in one direction; and yielding means operatively connecting the main valve and the pilot valve, this means comprising a second rod member movable in said opening between the two chambers, the connection being such that initial movement of the pilot valve in a certain direction causes movement of the main valve in a direction such that forces are developed in and transmitted through the connection opposing movement of the pilot valve in the initial direction, wherebymovement of the main valve toward and away from the main flow opening afiects flow through the passageway having said pilot valve controlled orifice therein. 1 v

8. Apparatus of the character claimed in claim '7, wherein both rod members are coaxial and longitudinally movable and the connection between the 'second'rod membe and the actuating member includes a spring.

9. Apparatus of the charactei claimed in claim the pressure of said fluid,

HENRY BEEKLEY.

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