US1830928A - Pump governor - Google Patents

Description

Nov. l0, 1931. c. A. CAMPBELL ET AL 1,830,928

PUMP GOVERNOR Original Filed Jan; 7, 1928 2 Sheets-Sheet l Nov. 10,- 1931. c. A. CAMPBELL ET AL 1,330,928

PUMP GOVERNOR Original Pld Jan. 7, 1928 2 vSheets-Sheet 2 Patented Nov.` 10, 1931 UNITED sierras PATENT OFFICE CHARLES A. CAMPBELL AND JAMES D. CARTIN, F WATER-TOWN, NEW YORK, AS'd SIGNORS TO THE JERSEY NEW YORK AIR BRAKE-GOMPANY, A CORPORATION lOl NEW PUMP GovERNon Application led January 7, 1928, Serial No. 245,170. Renewed AugustrS, 1.931.

This invention relates to fluid pressure regulators and will be described as embodied in a pump governor of the type used in railway air brakes, though some or all of the novel features are suited for general use and have particular utility in other air brake apparatus, for example-feed valves.

This application is subordinate to our prior application Serial No. 180,043, filed March 31, 1927, in which broad claims are presented to subject matter common `to the two cases. Said prior application discloses the use of a heat radiating structure between the valveand valve motor, a leakage interceptor on the valve stem, means fordirecting spent air from the pressure motor .in cooling relation with the heat intercepting means, and a dash pot for regulating the motion of the valve. mechanism. The broader claims to such features and combinations thereof, are presented in said prior application.

Referring to the invention as embodied in l a pump governor, the important objects are to limit or prevent the flow of steam or oil from the steam valve to the governor cylinder; minimizethe transmission of heat from companying drawings.

Figure 1 is a view principally in vertical axial section.

Fig. 2 is a plan view.

Fig. 3 is an enlarged fragmentary Vsection on the line 3--3 of Fig. 2.

The body of the steam valve is shown at 6. This is the valve that controls directly the Huid to be regulated and is typical of any valve for performing a similar function (cf. the main valve of a feed valve). The

valve seat is indicated at 7 and the valve at8. In order to keep the pump Warm when shut down, a bleed port 9 is formed in valve 8, as is usual. The valvebody 6 is connected in such a way that steam flows through the s valve body in the ldirection of the arrow 4and thus exerts an opening tendency on valve 8.

Valve 8 is formed integrally with a tub11 y bushing 12 is formed with a'seat for conical valve 15, which is formed vat the junction of stem 11 with a valve 8. The grooves 14 and valve .15' are provided to resist leakage of steam or oil along the stem, particularl when valve '8, is positioned between seat and the seat on bushing 12.

To divert suoli leakage as does occur, bushing 12 is'iformed withv an annular internal recess 16 above the range of travel of grooves 14on the stem 11 and this recess is vented freely to atmosphere by way of ports 17, recess 18 in bonnet 13 and passage 19.

YVithin recess16 the stem 11 is reduced or shouldered as shown at 21, which has the effect of assisting to check flow along the stemthrough the guide passagejin the top of -bushing 12. y

Supported in bonnet 13 by means of thin .fins 22 is cylinder housing 23 open at its lower end except for the sheet metalfdust excluder plate 24 pressed to place in a recess lprovided for it. Plate 24 has an air vent port 25.

Seated on `flange 26 in housing 23 and pendant therefrom is cylinder bushing 27' which is spaced from the hbusing laterally and at its lower end, both throughout its circumference. A notch 28 is formed in the lower margin of bushing 27 to serve as a vent port even ifthe space below the lower margin ,of the bushing should become clogged.

The upper end of bushing 27 has a project-Y ing flange 29 which seatson flange 26 and the upper face ofiiange29 is grooved at 31 to keep .gasket 32 from creeping. Gasket 32 sealsy the joinv between housing 23 and bushing 27 on the one hand and cap 33 on the other.

VTh'ecap 33 is formed with an annular plrojection' 34 on its lower or inner side in w ich is mounted a guide bushing 35 for hub eX- Vtension 36 formed on piston 37. The hub a and other obstructions.

extension and bushing serve as a dash pot to check sudden movements of the piston, which works in cylinder bushing 27 and aetuates main valve 8. This steadies the piston and permits the omission of a spring urging the piston 37 upward heretofore considered necessary.

l Piston 37 has a packing ring 38 and piston rod 39. Rod 39 is formed with an integral collar 4l which engages the lower side of the piston, and the rod, extending upward through hub 36 is peened or riveted over at its upper end to afford a rigid and permanently tight connection between the piston and rod. The lower end of rod 39 extends into and makes a close slip fit with the bore of tubular valve stem 1l. It is in thrust engagement at itslower end with valve 8, and the point of such engagement when the valve is closed is below the lower end of the valve guide in bushing 12.

rlhus the valve and the piston guide each the other and the construction is such that.

canting of each is prevented.

To permit a controlled discharge of pressure fluid (air) from the cylinder space above piston 37 a passage 42 (see Fig. 3) is cored or otherwise formed in cap 33 and cylinder housing 23. `This leads to the annular space surrounding` bushing 27 so that the discharging air assists to keep bushing 27 and housing 23 cool.

At some point in this passage a choke port must be provided, and for illustra ion there is shown a choke port forming the subject of a prior application by Charles A. Campbell, Serial No. 236,340, filed Nov. 28, 1927, and hence not claimed in the present application.

This choke structure includes a plug 43 I spring' seat 71 which is lockedrby threaded having a vertical cup-like chamberv 44 in which is mounted a free ball 45 of slightly smaller diameter. The interval between the ball and the surrounding wall of the cup serves as the choke port. A passage 46 formed in plug 43 directs the outflowing pressure fluid eccentrically against the ball 45 so that the ball is given a rotaryy motion which keeps the choke port clear of dust The capacity of passage 46 exceeds that of the interval around ball 45 so that passage 46 has no regulatory action.

, The pump governor chosen for illustration in the present case is of the well known duplex type and hence includes two diaphragm pin valves intended to function in alternation witheach other to maintain two different pressures. vOne diaphragm pin valve is shown in Fig. l in section and the other in elevation. As they are identical, except that sures, a description cf one will suilice, identishown) orother volume whose pressure variations are to control the opening and closing of valve 8. j

Supported in base 5l and sealed by gasket 55 is pin valve seat member 56. This is mounted in a recess which .contines gasket 55, and has a flange 57 which seats on shoulder 58 in base casting 5l. Flange 57 thus offers a lirm support for diaphragm 59 clampedlthereagainst by ring 6l and spring` box 62 of usual form, which last is screwed into the internally threaded upper portion of base 5l'.

Diaphragm 59 is open at the center as usual to receive a thrust plate and pin valve assemblyV of known form. lThis includes a thrustfplate 63 guided at'64 in the spring boX 62, a combined clamp screw and pin valve guide 65, threaded into the plate 63, a washer 66; a pin valve 67 and a spring 68 which holds the head of the pin valve 67 upward against thrust plate 63. Pin valve 67 coacts with port 69 in seat member 56 to open and close the same. Member 56 is ported to permit pressure Huid arriving by connection 54to act against the lower face of diaphragm 59 and to discharge through port 69 when pin valve 67 opens the port.

Certain details of the pin valve structure above described are novel. but are not a part of the present'joint invention and hence form the subject of alseparate application.

Threaded in spring-box 62 is adjustable cap 72. The spring seat sustains the upper end of loading spring 73 whose lower end carries the conical thrust member 74. Thrust member 74 engages thrust plate 63, a conical recess 75 being provided to position the thrust member and assure its centering in the thrust plate. The space above vdiaphragm 59 is vented to atmosphere by port 76. l a

The two diaphragm actuated pin valves,

` commonly called governor tops are used l'steam pressure which acts upward against valve 8, partially or wholly closing the valve 8.

TheV air escaping through the choke port cools the bushing 27, housing 23 and the space below piston 37, and is finally discharged to atmospherethrough port 25. In modern practice the use'of superheated steam entails temperatures as high as 700o F. in the valve body 6 and such temperature if allowed to prevail generally would affect adversely the desired smooth action of piston 37 and valve 8. The cooling effect of the discharging air, aided by partial thermal isolation effected by the use of. slender supporting Webs 22, and the diversion of steam leakage through the use of vented chamber 16, is effective to keep the temperature of the piston and governor tops to the desired relatively low value. The hand may be safely placed on cap 33 while valve body 6 is in the neighborhood of 700o F., hot enough to burn paint on the valve body.

The vented chamber 16 functions to divert leakage. In pumpl governors the leakage is steam or steam and oil. In feed valves for air brakes, which are functionally and strucand the oil, if it be permit-ted to lenter the regulating cylinder of any such device, causes mal-functions by gumming and causing the piston to stick. vThus the diverting chamber is a feature of particular' importance in pressure regulators generally because of oil diversion independently of the heat diverting function which it also performs in the pump governor above described.

What is claimed is 1. The combination of a valve body; a valve therein; a fluid pressure motor including a housing, a cylinder bushing spaced from said housing, and a piston arranged to actuate said valve, there being a vent port leading from the space to one side of said piston within the bushing to the annular space between said housing and bushing and thence to atmosphere; andpressure responsive means for admitting pressure fluid at varying rates to act against said piston.

2. The combination of a valve body; a valve therein having a stem; a guide for said stem projecting from said body; a fluid pressure motor including a housing, a cylinder bushing mounted in and spaced from said housing and a piston-in said bushing arranged to actuate said valve through said stem, there being a vent passage leading from the cylinder space at one side of said piston, through the space between said housing and bushing and thence past said guide to atmosphere; and pressure responsive means for admitting pressure fluid at varying rates to act against said piston.

3. The combination of a valve body; a valve therein having a stem; a guide for said ingl and? bushing' and-"thenepast said-guide for admitting! pressure-fluid atlvaryingffrates wmf-against said piston; alfheatfradig ating l supporting" connection ybetw'e'enfl said body and housing* 7 f 'l f 6 "75. "The combinationf of' a 'y valvekv 1 ibodyl; fa valve therein having shouldered Ais'tem ;=a` f fluidi'- p'ressur'e motor;- including1er-cylinder and pistoni"-andl having a" cylinder-vent? arrangedit'o discharge' pressure-'fluidlincooling relationwitthe cylind'rgsaidipistonJbe'ing in thrust relation with said stem kafgu-ide*for sai'd-L stem'l including a' 'leakageiintercep'tor comprising a vented 'chamber-[which'em braces-1' the shouldered-portion'- of the stem; and pressure responsive means-for admitting pressure fluid at varying rates to act against said piston.

6. The combination of a valve having a shouldered stem; a fluid pressure motor for actuating the valve through said stem; and means for intercepting leakage flow from the valve to the motor along the stem comprising a vented chamber distinct from said motor and through which the shouldered portion of the stem passes, and with the walls o-f which it makes slip fits on opposite sides of said shoulder. Y

7. The combination of a valve body; all valve therein having a hollow stem; a cylinder having a dash pot formed in one end thereof; a piston in said cylinder having a plunger extension working in said dash pot;

'tofatinosphere;fa-pressuref responsive-'meansturally similar the leakage 1s 'air andk oil,

a rod fixed in said piston and in thrust relai tion with and extending into said valve stem; a guide for said stem provided with leakage `intercepting means comprising a vented connection betweenk said valve body'and cyl-I luder; and pressure responsive means ar-` ranged to vary the leffective pressurein said piston.

' 48. The-combination ofa valve bodyaa valve therein; a fluid pressure motorI including a housing open at its lower end, a cylinder bushing spaced from said housing, a

piston working in said bushingand arranged to actuate said valve, and a thin sheet metal closure for the open lower end of said hous-A ing.y said closure being belowsaid bushing and being ported, there being a vent passage from the space above the piston .through the space between the bushing and housing and thence beneath the bushing to the portjin said closure; and pressure responsive means l for admitting pressure fluid at varying rates to the space above the piston. Y

9. The combination of a valve body a valvetherein; a fluid pressurevmoto'r including a housing open at its'lowerend,la cylinder bushing spaced from said housing, a piston working in said bushing and arranged to actuate said valve, and a thin sheet metal closure for the open lower end of said housing, said closure being below said bushing and being ported, there being a vent passage rom the space above the piston through the spacefbetween the bushing and housing and thence beneath the bushing to the port' in said Vclosureypressure responsive means for admitting pressure fluid at varying rates to the space above the piston; and means for supporting said housing comprisingk a plurality of slender blade-like struts extending between said housing and a portion of the valve body. p

In testimony whereof We have signed our names to this specification.

CHARLES A. CAMPBELL.

JAMES D. CARTIN.

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