US499450A - Fluid-pressure governor for pumping-engines - Google Patents

Description

(No Model.)

F. L. CLARK. FLUID PRESSURE GOVERNOR FOR PUMPING ENGINES.

No. 499,450. Patented June 13.1893..

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m5 Mann UNITED STATES PATENT OFFICE.

FRANCIS L. CLARK, OF WILKINSBURG, ASSIGNOR TO THE \VESTINGHOUSE AIR BRAKE COMPANY, OF 'PITTSBURG, PENNSYLVANIA.

'FLUlD-PRESSURE GOVERNOR FORVPUMPlNG-ENGINES.

SPECIFICATION forming part of Letters Patent No. 499,450, dated June 13, 1893.

Application filed December 9 1892. Serial No. 454,554. (No model.)

To all whom it may concern.-

Be it known that I, FRANCIS L. CLARK, a citizen of the United States, residing at WVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered a certain new and useful Improvement in Fluid-Pressure Governors for Pumping-Engines, of which improvement the following is a specification.

The object of my invention is to provide an improved governing device for pumping or compressing engines; and to this end it consists of a novel governing device in which the supply of-fluid to the engine is controlled by fluid pressureh and further, in certain improvements in the construction of such devices which are also applicable to other devices operative by fluid pressure.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings: Figure '1 is a central longitudinal section through a governing device illustrating an application of my invention, and Fig. 2, a similar section through a portion of the same showing some of the parts in different positions from those which they occupy in Fig. 1.

The fluid, the supply or flow of which is to be regulated or controlled, enters at the supply opening 1, and flows through the valve port 2 and passage 3; the valve 4 being normally held open or unseated by a spring 5 bearing against one side of a piston 7, which is fitted in a chamber 6 and secured to the end of a valve stem 8. The chamber 6 and the valve chamber 9 are separated by means of a partition 10, which is perforated to admit the passage of the stem 8; and, in order to prevent leakage of the supply fluid from the chamber 9 to the chamber 6, a projecting seat 11, on which the valve 4 seats when open, is formed on the partition 10. The chamber 6 is open to the atmosphere through a passage 12 shown in dotted lines in Fig. 1.

The flow of fluid through the port or passage 2 is controlled by the valve 4, which is moved toward its seat 14 by the fluid pressure acting on the back of the piston 7 against the pressure of the spring 5 and the upward pressure of the supply fluid below the valve.

The controlling fluid, by the pressureof which the piston 7 is operated, enters through the nozzle 13 and passages 15 and 16 into the chamber 17 where it acts against the lower side of the diaphragm 18, which is held in its normal position, as shown in Fig. 1, by the pressure of the spring 19. The outer edge of the diaphragm 18 is clamped between the shoulder 21 and .the ring or abutment 23, by means of that portion, 22, of the casing 27 which incloses the spring 19. The lower side of the ring or abutment 23 is beveled or cut away from its bearing on the casing to its inner edge, in such a manner that the disk 24, which fits'neatly in the central opening in the ring, projects a little below the inner edge of the ring when the disk is in its lower position; and the lower surface of the disk is flush with the lower surface of the ring when the disk is in its upper position, thereby forming one continuous surface without any intervening space between the disk and ring. The

disk 24has a hub or projection 25 formed on it against which one end of the spring 19 bears; and the upper end of the spring 19 bears against the screw plug 26, whichis ad justable in the casing 27 and is covered by the screw cap 28.

The central portion of the diaphragm 18 is clamped between the disk 24 and the clamping piece 29 which is secured in place by means of a threaded projection 30 which is screwed into a central bore formed in the disk and hub. The stem 33 of the valve 34 passes through an opening 32 in the clamping piece 29 and has formed on its upper end a shoulder 35 which abuts against the inner end of the bore 31, and forms a bearing for one end of a spring 36; the other end of the spring 36 bears against the projection 30 on theclamping piece 29, so that the spring tends to hold the head 35 against the inner end of the bore 31.

When the pressure of the fluid in the chamber 17 is below the maximum required to 'compress the spring 19, and lift the diaphragm 18, the valve 34 is held to its seat in the position shown in Fig.1, and closes communication, through the passages 37 and 38, between the chamber 17 and the piston chamber 39. When the valve 34 is in the closed position, the form of the diaphragm is that of a flat disk which lies in the plane of its outer edge which is clamped by the ring 23. The lower flat surface of the disk 24 then coincides with and forms a bearing fora large portion of the upper flat surface of the diaphragm.

When the pressure of the fluid in the chamber 17 rises above the desired maximum, the pressure on the under side of the diaphragm overcomes the tension of the spring 19, and moves the diaphragm 18 and disk 24 upward, and with them the valve 34. These parts are then in the positions shown in Fig. 2. The upward movement of the diaphragm and disk 24 is small and is stopped, by the projection 40 on the lower end of the spring casing 27, in the position shown in Fig. 2, in which position the lower edge of the disk 24 is flush with the inner lower edge of the ring 23. The lower surfaces of the ring 23 and the disk 24 then present a continuous surface for the support of the diaphragm and against which the diaphragm bears without forming wrinkles or sharp bands, such as are formed with other constructions and which cause the rapid destruction of the diaphragm.

With my improved construction the whole surface of the diaphragm has a firm bearing for its support against the pressure of the fluid beneath it, when that pressure is greatest and most capable of damaging the diaphragm if unsupported. The form of the support is, as nearly as possible, that which the diaphragm will take when deflected by fluid pressure; and the closeness of fit between the disk 24 and the ring 23 prevents the formation of corrugations in the diaphragm which are caused by the diaphragm being forced between its supports by the pressure of the fluid.

In my improved construction the diaphragm is unsupported by the ring 23 only when the pressure is below the maximum, and not great enough to distort the narrow annular portion which is unsupported; but when, for any reason, the pressure below the diaphragm is increased above the maximum, the diaphragm is supported over its whole surface. These changes sometimes occur very'suddenly and if there is aspace between the disk and the outerbearing, the diaphragm is forced into the space anda permanent corrugation is formed. This has been a very serious difficulty with metallic diaphragms employed in devices of this kind, as it not only caused them to wear out quickly but alfected the regulation of the device by changing the resistance to movement after being adjusted for certain pressures.

The spring 36 causes the head 35 of the valve stem to be held always in contact with the inner end of the bore 31, and thereby compensate for lost motion which may be due to dilferent adjustments of the clamping piece 29. In some constructions in which a similar valve has been used, but with the head on the valve stem bearing directly against the screw plug 30, the wear between the valve and the plug has been so great as to permit the upward movement of the diaphragm without lifting the valve 34 far enough from its seat to fully open the passage 37. This difliculty is obviated by the spring 36, which always keeps the head 35 pressed against the inner end of the bore, and insures the lifting of the valve with the rising of the diaphragm. The strength of the spring 36 is sufficient to hold the valve up as described, and it need not be any greater, because, on account of its arrangement relatively to the other parts, it is not compressed by the greater pressures by which the diaphragm is raised or depressed.

When the pressure below the diaphragm 18 exceeds the required maximum and lifts the diaphragm and valve 34, a portion of the fluid in the chamber 17 flows through the passages 37 and 38, into the piston chamber 39, and acting on the piston 7, moves it downwardly, compressing the spring 5 and closing the valve 4.

The fluid which is controlled by the valve 4 is usually the steam supply to an engine; and the fluid in the chamber 17, which lifts the diaphragm l8 and acts on the piston 7, may be a fluid pumped or compressed by the engine, or whose pressure is due to the operation of, and depends on the speed of the engine. The pressure of the fluid in the chamber 17 may, however, vary on account of other causes than the speed of the engine, and such variations operate to control the passage of fluid through the port or passage 2. The fluid flowing through the port2 may be the same as that in the chamber 17, and my improvement is not limited in its employment to the control of the supply of steam or other fluid to an engine, as the fluid after passing through the passage 3 may be utilized for other purposes.

When the pressure below the diaphragm is reduced to or below the desired maximum the valve 34 is closed, and the fluid in the chamber 39 and the passages 38 and 37 leaks by the piston 7 and out through the passage 12, shown in dotted lines, thereby permitting the pressure below the valve 4 and the pressure of the spring 5 to open the valve 4 and permit fluid to flow through the port 2.

While the construction and relation of the ring 23, disk 24, and diaphragm 18, and also the relation of the valve 34 and spring 36, are specially adapted for use in connection with the other parts as shown in the drawings, they may be used With equal advantage in other fluid pressure devices, or in other pressure regulators and I do not therefore limit myself to their employment in connection with the devices shown. Further, while the diaphragm as shown is subjected to fluid pressure on only one side it may be subjected to fluid pressure on both sides,and be arranged so as to be supported in both extreme positions.

I claim as my invention and desire to secure by Letters Patent 1. A movable diaphragm secured at its outer edge and having a connected central disk or plate which fits accurately in a stationai'y abutment, so that in one position of the diaphragm and disk the contiguous edges of the disk and abutment are in the same plane and the surfaces bounded by these edges form a continuous bearing for the diaphragm, substantially as set forth.

2. A movable diaphragm secured at its outer edge and having a connected central disk or plate fitting accurately in a stationary abutment, and an inclined surface on the abutment which forms a bearing for part of the diaphragm and is flush with the surface of the disk when the disk is at one extremity of its movement, whereby a continuous bearing is formed for the diaphragm, substantially as set forth.

3. The combination of a movable diaphragm secured at its outer edge, an abutment against which a portion of the diaphragm bears at one extremity of its movement,a disk or plate accurately fitting an opening in the abutment and secured to and movable with the diaphragm, and a stop for limiting the movement of the disk, so arranged that the surface of the disk next to the diaphragm is stopped flush with the surface of the abutment where by a continuous bearing is formed for the diaphragm, substantially as set forth.

4. In a fluid pressure device, the combination, with a casing, of a chamber therein, a diaphragm in the chamber, an annular abutment or ring bearing on the outer edge of the diaphragm and clamped in place with it,'a movable disk or plate accurately fitting in the ring and secured to and movable with the diaphragm, and a stop for limiting the movement of the disk or plate to aposition in which the surface of the disk next to the diaphragm is flush with the similarly located surface of the ring, whereby a continuous bearing is formed for the diaphragm, substantially as set forth.

5. In a fluid pressure device, the combination, witha movable diaphragm, of a valve connected with and movable thereby and seated by a rigid connection between the valve and the diaphragm and unseated by means of an elastic connection between the valve and the diaphragm, substantially as set forth.

6. In a fluid pressure device, the combination, with a diaphragm, of a center piece secured to the diaphragm, a valve loosely connected to the center piece and which is pressed to its seat by direct contact with the center piece whenthe diaphragm is moved in one direction and a spring which tends to hold the valve in contact with the center piece and which forms an elastic connection by which the valve is unseated when the diaphragm moves in the other direction, substantially as set forth.

7. In a fluid pressure device, the combination with a diaphragm, which is movable in one direction by fluid pressure, of a spring which moves the diaphragm in the opposite direction, a valve loosely connected to the dia:

FRANCIS L. CLARK.

Witnesses:

T. J. HOGAN, DARWIN S. WOLCOTT.

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