US3700355A - Emergency shutdown mechanism for centrifugal compressor - Google Patents

Abstract

A switch is mounted on a bracket fixed in the compressor casing and has contacts connected in a control circuit means for the impeller driver. Upon actuation, the contacts of the switch are cooperable with the circuit means to deenergize the driver. A lever is pivotally mounted on the bracket and in normal position restrains actuation of the switch contacts. Upon the impeller driving shaft shifting from normal operating position, a projection on the shaft moves the lever from normal position permitting actuation of the switch contacts to effect stoppage of the impeller driver.

Description

United States Patent Anderson et al.

[54] EMERGENCY SHUTDOWN MECHANISM FOR CENTRIFUGAL COMPRESSOR [72] inventors: Carl M. Anderson; James W. En-

dress, both of Syracuse, NY.

[73] Assignee: Carrier Corporation, Syracuse, N.Y.

[22] Filed: July 8, 1971 [21] Appl. No.: 160,691

[52 us. Cl ..417/33, 192/129 A, ZOO/61.45, 417/44 51 Int. Cl ..F04b 49/02 [58] Field of Search ..417/1, 33, 44; 308/15; 184/64; 200/6145 R; 192/129 A [56] References Cited UNITED STATES PATENTS Schenck ..192/ 129 A 1 Oct. 24, 1972 Blum ..200/61.45 R Conrath ..200/61.45 R

Primary Examiner-Carlton R. Croyle Assistant Examiner-R. J. Sher Attorney-Harry G. Martin, Jr. et al.

[57] ABSTRACT A switch is mounted on a bracket fixed in the compressor casing and has contacts connected in a control circuit means for the impeller driver. Upon actuation, the contacts of the switch are cooperable with the circuit means to deenergize the driver. A lever is pivotally mounted on the bracket and in normal position restrains actuation of the switch contacts. Upon the impeller driving shaft shifting from normal operating position, a projection on the shaft moves the lever from normal position permitting actuation of the switch contacts to effect stoppage of the impeller driver.

4 Claims, 4 Drawing Figures P'ATENTEDHBI 24 I972 SHEET 1 BF 2 L': c \i I FIG. I

INVENTOR. CARL MANDERSON ATTORNEY PATENTED 24 I97? 3,700,355

sum 2 or 2 CARL M. ANDERSON BY JAMES DRESS ATTORNEY EMERGENCY SIIU'IDOWN MECHANISM FOR CENTRIFUGAL COMPRESSOR BACKGROUND OF THE INVENTION Various forms of automatic shutdown mechanisms have been proposed to stop centrifugal gas compressors in the event the shaft carrying the impeller shifts from normal operating position. Certain of said mechanisms function satisfactorily. However, they are expensive to manufacture and assemble into the compressor structures. This invention has as an object an automatic emergency shutdown mechanism for a centrifugal gas compressor embodying a structural arrangement, particularly economical to manufacture and assemble into the compressor structure and which is rugged and durable in use.

SUMMARY OF THE INVENTION A commercially available switch having a spring actuated plunger for automatically actuating the contacts, such as a Microswitch, is fixed on a bracket in the compressor casing. A lever' pivotally mounted on the bracket is arranged with one end portion for engagement by a projection on the impeller shaft as it shifts from normal operating position. Upon such engagement, the lever is swung out of contact with the actuating plunger of the switch, deenergizing the impeller driver through a control circuit means in which the contacts of the switch are connected. Upon movement of the lever by the shaft, the switch contact plunger maintains the end of the lever spaced from the path of movement of the projection on the shaft.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a lengthwise sectional view of a centrifugal compressor embodying our invention with a portion of the casing shown in elevation and including a schematic representation of the driver.

FIG. 2 is an enlarged view of the safety shutdown mechanism as shown in FIG. 1.

FIG. 3 is a view taken on line 3-3, FIG. 2, and

FIG. 4 is a view taken on line 4-4, FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Theimpellers 10, 11 are mounted on animpeller drive shaft 12. Theshaft 12 is journaled in bearings mounted in a casing having upper and lower sections l3, l4 detachably secured together as bybolts 15, see FIG. 1. A driver 17 as an electric motor, steam turbine or the like is operatively connected to theimpeller shaft 12 to efl'ect rotation thereof.

Control circuitry is provided for the driver 17 and includes acontrol element 20 connected byline 21 to the contacts of aswitch 23. When the contacts of theswitch 23 are actuated, the control element functions to deenergize the driver 17.

A lug 26 is formed on the inner surface of thetop casing section 13. Abracket 27 is mounted on the lug 26 as bybolts 29. Thebracket 27 is of right angle form in cross section havingside flanges 30, 31. Theflange 31 is formed withelongated apertures 35 through which themounting bolts 29 extend. With this arrangement, thebracket 27 may be adjusted toward and from theimpeller drive shaft 12.

Theswitch 23 is fixed to theflange 31 of the bracket, as byscrews 40, and is constructed with a contact actuatingplunger 43 extending through anaperture 44 in theflange 30 of thebracket 27. u

Alever 45 is pivotally mounted intermediate its ends to theflange 30 bybolt 47. As thelever 45 is moved about itspivot 47, one end of the driver is moved in to and out of engagement with theplunger 43. The surface of the lever contacting theplunger 43 is formed with adepression 50. Theplunger 43 is spring pressed outwardly and when the outer end of the plunger is seated in therecess 50, thelever 45 is yieldingly restrained against movement about thepivot 47 In this position, shown in full line in FIG. 2 and in dotted line in FIG. 3, the opposite end of the lever is located in proximity to theimpeller shaft 12.

Theimpeller shaft 12 is provided with aprojection 51 located to engage the free end of thelever 45 upon the impeller shaft shifting axially or radially from normal operating position. Upon theprojection 51 engaging thelever 45, it is moved from the dotted line position in FIG. 3 to the full line position. Accordingly, the opposite end of thelever 45 is moved out of engagement with theplunger 43. The movement of the spring press plunger is such that a substantial end portion of the plunger extends outwardly from theflange 30 of the bracket, as shown in FIG. 4, and serves to prevent return movement of thelever 45. That is, when thelever 45 has been tripped, it is held in trip position shown in full line, FIG. 3, with the free end of the lever spaced from the path in which theprojection 51 moves, the path being indicated by theline 53. This is advantageous in that it prevents theprojection 51 from engaging with the free end of the lever during reverse rotation of the compressor. During the coast down period of the centrifugal compressor, there is a time when the high pressure gas will backflow through the machine .and effect reverse rotation of the impellers and theshaft 12.

The shutdown mechanism described embodies a low cost structure which is conveniently mounted in the compressor casing, and which functions to deenergize the compressor driver prior to the movement of the impellers and impeller drive shaft from normal operating position, prior to the engagement of the rotating parts with the frame structure or casing of the machine.

We claim:

1. A centrifugal refrigeration compressor including a casing, animpeller drive shaft joumaled in said casing, a driver operatively connected to said shaft for effecting rotation thereof, said shaft having a radially extending projection, a safety shutdown mechanism for deenergizing said driver upon said impeller shaft shifting from normal operating position, said mechanism comprising a control circuit means for said driver, a bracket fixedly mounted in said casing, a switch mounted on said bracket and having contacts connected in said control circuit and operable when actuated to cause deenergization of said driver, said contacts being mounted in an enclosure, an axially movable contact actuating plunger, means yieldingly urging said plunger outwardly out of said enclosure for actuation of said contacts, a lever pivotally mounted on said bracket for movement in to and out of engagement with said plunger, said lever normally engaging said in claim 1, wherein upon movement of said lever out of engagement with said plunger for outward movement thereof, said plunger is effective to maintain said lever out of normal position.

4. A centrifugal refrigeration compressor as set forth in claim 1, wherein the axis of the pivotal mount for said lever is located in spaced parallel relation to the axis of said plunger and said impeller drive shaft.

Claims (4)

1. A centrifugal refrigeration compressor including a casing, an impeller drive shaft journaled in said casing, a driver operatively connected to said shaft for effecting rotation thereof, said shaft having a radially extending projection, a safety shutdown mechanism for deenergizing said driver upon said impeller shaft shifting from normal operating position, said mechanism comprising a control circuit means for said driver, a bracket fixedly mounted in said casing, a switch mounted on said bracket and having contacts connected in said control circuit and operable when actuated to cause deenergization of said driver, said contacts being mounted in an enclosure, an axially movable contact actuating plunger, means yieldingly urging said plunger outwardly out of said enclosure for actuation of said contacts, a lever pivotally mounted on said bracket for movement in to and out of engagement with said plunger, said lever normally engaging said plunger and restraining outward movement thereof, said lever having an end portion terminating in close adjacency to the path of revolution of said projection, said lever being movable about said pivotal mounting out of engagement with said plunger upon contact by said projection.

2. A centrifugal refrigeration compressor as set forth in claim 1, wherein said lever is formed with a depression for the reception of the outer end of said plunger.

3. A centrifugal refrigeration compressor as set forth in claim 1, wherein upon movement of said lEver out of engagement with said plunger for outward movement thereof, said plunger is effective to maintain said lever out of normal position.

4. A centrifugal refrigeration compressor as set forth in claim 1, wherein the axis of the pivotal mount for said lever is located in spaced parallel relation to the axis of said plunger and said impeller drive shaft.

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