US2242367A - Valve lifter - Google Patents

Description

May 2o, 1941.

J. NAAB 2,242,367

VALVE LIFTER Filed Feb. 2', 1959 HIS ATTORNEY Patented May 20, 1941 s Peli VALVE LIFTER Julius Naab, Easton, Pa., assignor to Ingersoll- Rand Company, Jersey City, N. J., a corporation of New Jersey 2 Claims.

This invention relates to compressors, and more particularly to a valve lifter for controlling the loaded and unloaded periods of a compressor.

One object of the invention is to assure against leakage of pressure fluid through the valve lifter to the atmosphere.

Another object is-to enable the power device of the valve lifter to be serviced at any time, irrespective of whether the compressor is in operation or idle.

A further object is to eliminate the necessity of frequent inspections and replacements of the parts comprising the power element of the valve lifter.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this speciiication and in which similar reference numerals refer to similar parts,

Figure l is an elevation, in section, of a valve lifter constructed in accordance with the prac- `tice of the invention and a compressor inlet valve to which it is applied, and

Figure 2 is an elevation, in section of a modified form of the invention.

Referring more particularly to the drawing, designates a portion of a compressor casing and 2| a valve assembly which controlsthe admission of fluid from a channel 22 into a compression chamber 23 in the casing 20.

The valve assembly 2| is shown as being of a conventional type comprising a stop plate 24 seated in an inner wall 25 of the casing 2|) and having ports 26 for the passage of the fluid into the compression chamber 23. A valve seat 21 rests upon the stop plate 24 and likewise has ports 28 which are controlled by spring-pressed valves 29 for admitting fluid from the channel 22 into the compression chamber 23.

T-he valve seat 21 supports a sleeve 30 which extends into a bore 3| in an outer wall 32 of the casing 20 and has ports 33 to afford communication between the channel 22 and the interior of the sleeve. The sleeve 30 is secured to the valve seat by bolts 34 and has an internal flange 35 in its outer end from which depends an integral annular wall 36.

The interior or opening 31 of the wall 36 also extends through the flange 35 and serves as a guide for a valve lifter 3B whereby the valves 29 are unseated to permit of uninterrupted communication between the compression chamber 23 and the channel 22 whenever conditions in the compressing system require the unloading of the compressor. The valve lifter 38 comprises,

inthe present instance, a piston portion 33 which is slidable in the opening 31 and has a flange 49 the outer surface 4| of which cooperates with the adjacent end 42 of the wall 36 to normally prevent the passage of ud through the opening 31. Fingers 43 on the flange lil extend into the ports 28 and terminate a slight. distance above the valvesv 29 so that they will be out of contact Ywith the valves during the normal operation of the compressor. v

The piston 39 is hollow and its outer end wall 44 serves as a seat for an end'oi a spring 45 seated upon the valve seat 21 to urge the valve lifter 38 outwardly and to maintain the flange 40 in engagement with the surface 42 of the annular wall 36.

The mechanism that supplies the powerl required for actuating the Valve lifter 38 is arranged coaxially with the valve assembly 2|. It comprises a casing 46 having a skirt 41 extending into the bore 3|. On the periphery of the casing |56 is a liange 48 through which extend bolts 49 that are threaded into the wall 32 of the compressor casing to maintain the skirt 41 in the bore 3|.

The casing 46 is hollow throughout, having an opening 5U into the inner end of which eX- tends a plunger 5| which preferably fits loosely in the opening 56 and has a stem 52 terminating in a foot-piece 53 to engage the end of the piston 39. At the inner end of the plunger is an external flange 54 to engage the adjacent end 55 of the casing 46 for preventing the passage of fluid along the peripheral surface of the plunger and thus through the casing.

In the outermost end of the plunger 5I is a concavity 56 to receive a flexible sack 51, preferably of rubber, which lies in the outer end of the opening 50 to serve as a receptacle for pressure fluid employed for actuating the plunger 5|. At the mouth of the sack 51 are lateral inner and outer flanges 58 and 59, respectively, and the latter ange seats upon the outer end of the casing 46 and is clamped thereagainst by a plate 60 that serves as a cover for the casing 46.

The flange 58 also seats against the plate 69 and is preferably provided with annular ribs 6| that extend into grooves 62 in the inner surface of the plate 60 to 4further preclude leakage of fluid between the cooperating surfaces of the flange 58 and the plate 69. The ribs 6| are held firmly in engagement with the grooves 62 by a plate 63 having a hollow stem 64 projecting through the plate 66 for introducing pressure uid into the sack 51. A nut 65 threaded 0n the stem 64 seats against the outer surface of the plate 60 to press the plate 63 against the ilange 58.

To the end that the sack 51 may be fully capable of withstanding the flexion to which it will be subjected in operation, the annular portion 66 adjoining the flanges 58 and 59 and lying directly in the mouth of the opening 50 is of materially greater thickness than the remaining portions of the sack and, in order that the sack proper may be readily responsive to the pressureof the iluid introduced thereinto, the body pori tion of the sack is of gradually decreasing thickness from the annular portion 66 to the central bottom part 61 of the sack.

In the assembled position ofthe cage 48 they skirt 41 is spaced a slight distance from the adjacent end of the sleeve 33. This spacing of the skirt may vary, as required, to assure the.

lagainst the ange 59. The bolts 10 thus serve to secure the plate 60 to the cage 46 and also to clamp the valve assembly securely in position in the compressor.

In practice, during the time the pressure value of the fluid in the compressing system is below -the predetermined .maximum value intended to be maintained in the system the valve lifter 38 occupies the retracted position in which the ngers 43 are out of `engagement with the valves 29. The valve lifter will be held in this position by the spring 45 which will also supply the force for norm-ally pressing the flange 54 against the end surface 55 of the cage. Owing to this `arrangement the inner end of the lopening 50 will be sealed and the sack 51 may be uncovered for inspection, or such other attentions which it may require, without stopping the compressor.

The parts comprising the valve lifter will remain in the .positions described until the pressure uid in the compressing system attains the maximum predetermined value. Pressure fluid is then admitted into the sack 51, by suitable devices (not shown), and will actuate the plunger 5I towards the valves. This movement of the plunger will cause the ngers 43 to unseat the valves 29 and thereby communicate the compression chamber 23 with Ithe channel 22. The valves will remain unseated until fthe pressure of the uid in the compressing system again falls to a predetermined low value. The devices controlling the pressure iluid supply to the sack will then operate to deate the sack, whereupon the spring will actuate the valve lifter 38 rto release the valves 29 and .the load will then again be applied to the compressor.

In the modied form of the invention shown in Figure 2, the sack, designated by 12, carries onlythe flange 59 which is clamped between the .plate 60 and the cagek46 by the bolts 10 and nuts 1 I. f The annular pontion 66 and the body portion of the sack are identical with the corresponding portions of the sack shown in Figure 1, and a conduit 13 is threaded .to the plate 60 and communicates with the interior of the sack through a port 14 in the plate for conveying pressure uid to and from the sack for operating the plunger.

2. An actuator, comprising a casing, a iiexiblev sack in the casing, inwardly and outwardly extending Ilanges at the mouth of and integral with the sack, a member rto press the outwardly extending flange against thecasing, means for clamping the inwardly extending Iiange against the member, and interlocking portions on fthe `member and the inwardly extending flange for lpreventing relatively lateral movement between said member and the inwardly extending ange.

. JULIUS NAAB.

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