US1922911A - Compressor governor - Google Patents

Description

COMPRES SOR GOVERNOR Filed May 25, 1928 llll l6 l7 l5 l7 i H {4! MI" "W W I q ,m a /0 5 5'2 I,

as itii I HUI INVENTOR CLYDE C. FARMER ATTORNEY Patented Aug. 15, 1933 COMPRESSOR GOVERNOR Clyde 0. Farmer, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a Corporation of Pennsylvania Application May 23, 1928. Serial No. 279,956

3 Claims. (Cl..137-153) This invention relates to governors adapted more particularly for the control of steam driven fluid compressors or pumps.

Superheated steam is extensively employed on locomotives at the present time at a high pressure of for example 275 pounds and at a high temperature for example of I degrees.

The high temperature seriously interferes with the proper lubrication of the piston which operates the steam controlling valve and also iniuriously afiects the temper of the spring which acts on the piston.

One object of my invention is to provide means for insulating the regulating portion of the steam governor from the heat action of the steam.

Another object of my invention is to provide a generally improved steam pump governor which can be more cheaply manufactured, and in which parts subject to wear may be easily renewed and in which maintenance expense is reduced to a minimum.

Other objects and advantages will appear in the following more detailed description of the invention.

In the accompanying drawing, the single figure is a central sectional view of a steam pump governor embodying my invention.

The steam pump governor shown in the drawing is of the so-called double top type, but my improvements may also be applied in connection with a single regulating top type of governor.

The governor comprises a steam valve body section 1, a piston cylinder section 2, and a cylinder head 3. The cylinder section 2 is provided with a cylindrical boss 4 which fits into an annular recess in the steam valve body 1, and the sections 1 and 2 are clamped together by bolts 5, a gasket 6 being interposed between the sections.

The cylinder head 3 is clamped to the cylinder section 2 by bolts '7, a gasket 8 being interposed between the head 3 and the section 2. The steam valve body 1 is provided with a partition wall 9 which separates a steam inlet chamber 10 from the steam outlet chamber 11, a steam inlet pipe 12 being connected to chamber 10 and a steam outlet pipe 13 to chamber 11.

Having screw-threaded engagement in the wall 9 is a seat bushing 14 provided with a seat for the steam valve 15. In order to prevent the bushing 14 from unscrewing when the parts are assembled, a pin 16 is secured in the cylinder section 2 and extends downwardly into chamber 11, in such position as to engage in one of a plurality of recesses 17, cut in the flange of the bushing, in case the bushing tends to unscrew.

A removable bushing 18 has screw-threaded engagement in the cylinder section 2 and is provided with a central bore for receiving the stem 19 0f the valve 14, the stem 19 being provided with annular grooves 20 to reduce leakage of steam past the stem.

Secured to the upper end of the stem 19 is a piston 21, the piston ring 22 of which is adapted to engage the inner cylindrical face of a slip bushing 23. The slip bushing 23 is provided with an annular flange 24 which engages in a recess in the cylinder section 2 and is clamped in position when the head 3 is secured to the cylinder section 2.

The governor tops each comprise a spring box 25 having screw-threaded engagement in the cylinder head 3, a flexible diaphragm 26 being clamped in position by an interposed diaphragm ring 27, when the spring box 25 is screwed in.

A follower plate 28 engages one side of the diaphragm and said follower is subject to the pressure of an adjustable spring 29, the adjustment being effected by a screw 30, having a screw- 30 threaded engagement in the ,upper end wall of the spring box.

A valve seat bushing 40 is mounted in a bore in a partition wall 31, which separates piston chamber 32 from chamber 33, and a valve 34 35 is adapted to engage the seat in said bushing. Said valve is provided with a follower head adapted to engage the diaphragm 26and is centrally recessed to receive a stem 35 carrying a disk 36 at its lower end.

One end of a coil spring 3'? engages the disk 36 and the other end of the spring engages a spring plate 38, which is held in place by pins 39.

In the chamber 41 below piston 21 there is provided a ledge 42 upon which rests a barrier plate 43. Said plate is centrally dished and forms a support for a spring 44 adapted to engage the piston 21 and urge same in an upward direction. The chamber 45 below the barrier plate 43 is connected'by a port 46 with a passage 47, which leads to an atmospheric vent pipe 48, and the plate 43 is provided with a plurality of openings 49 which afiord communication between the chambers 41 and 45.

An annular chamber 50 in the bushing 18 surrounds the stem 19 and communicates with passage 47.

The left hand governor top 25 is known as the low pressure top and the right hand governor top as the high pressure top. The spring 29 of the low pressure top is responsive to a lower pressure of fluid acting on its diaphragm 26 than the spring 29 of the high pressure top.

In operation, the diaphragm chamber 33 of the low pressure top is supplied with fluid at the pressure compressed by the compressor into the usual main reservoir (not shown) under certain conditions, while under other conditions the chamber 33 of the high pressure top is supplied with fluid under pressure from the main reservoir.

Assuming main reservoir pressure as being supplied to chamber 33 of the low pressure top, when by operation of the compressor, the main reservoir pressure has been increased to a predetermined degree for which the spring 29 of the low pressure governor top may be adjusted, the diaphragm 26 is deflected upwardly, permitting valve 34 to be unseated by spring 37.,

Fluid under pressure is then supplied from chamber 33 to piston chamber 32, and piston-21 is then shifted downwardly, so thatthe steam valve 15is brought to its seat, thus cutting off the further supply of steam to the compressor and causing the compressor to cease operating. When the pressure of fluid in the main reservoir andin chamber 33 has been reduced below a predetermined degree, the spring 29 of the low pressure governor top operates to deflect the diaphragm 26 downwardly, so that the valve 34 is moved to its seat. The supply of fluid under pressure to the piston chamber 32 being thus cut off, the fluid pressure in said chamber leaks off, through a restricted port in the plug 60.

The spring 44 then acts on the piston 21 to shift same upwardly, so that the steam valve 15 is again unseated, permitting the supply of steam to the compressor. The compressor then starts operation to compress fluid into the main reservoir.

When fluid from the main reservoir is supplied to the diaphragm chamber 33 of the high pressure governor top 25 at the right, the high pressure governor top then controls the operation of the compressor governor in the same manner as the low pressure governor top functions.

In order to relieve the steam pipes .12 and 13 of the strain due to supporting the governor, a

separate supporting member 51 is provided and the lower portion of the steam valve body 1 is provided with a boss 52 which is tapped for a bolt 53, bywhich the governor is secured to the member 51.

Possible leakage of steam from chamber 11 around the stem 19 to the chamber will be leaking steam, so that the temperature will not rise sufliciently to interfere with the lubrication of thepiston 21.

-While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, What I cl im as new and desire to secure by Letters Patent, is:

1; In a steam pump governor, the combination with a steam valve body, a steam valve mounted in said body, a cylinder section, a piston mounted in said section, a partition wall in said section, and a stem connecting said valve with said piston and extending through a bore in said wall, of a spring acting on said piston and a barrier plate interposed between said wall and said piston for supporting said spring and to prevent conduction of heat from the partition to the spring, said plate providing an air space between the partition wall and the plate.

2. In a steam pump governor, the combination with a cylinder casing, a piston mounted in said casing, a partition wall in said casing, a steam valve, a bushing mounted in said wall, and a stem connecting said valve with said piston and extending through a bore in said bushing, of a barrier plate interposed between said piston and said wall and providing an air chamber between said wall and said plate, an'atmospheric vent connected to said chamber, and an annular chamber in said bushing, surrounding'said stem and connected to said atmospheric vent.

3. The combination with a valve body, of a valve therein, a cylinder, a piston in said cylinder for operating said valve, a partition wall between said valve body and said cylinder, and a plate disposed between said wall and said piston and forming a closed air chamber between the plate and said wall to minimize the conduction of heat to said plate and said piston.

CLYDE C. FARMER.

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