U.S. patent number 3,700,355 [Application Number 05/160,691] was granted by the patent office on 1972-10-24 for emergency shutdown mechanism for centrifugal compressor.
This patent grant is currently assigned to Carrier Corporation. Invention is credited to Carl M. Anderson, James W. Endress.
United States Patent |
3,700,355 |
Anderson , et al. |
October 24, 1972 |
EMERGENCY SHUTDOWN MECHANISM FOR CENTRIFUGAL COMPRESSOR
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.
Inventors: |
Anderson; Carl M. (Syracuse,
NY), Endress; James W. (Syracuse, NY) |
Assignee: |
Carrier Corporation (Syracuse,
NY)
|
Family
ID: |
22578003 |
Appl.
No.: |
05/160,691 |
Filed: |
July 8, 1971 |
Current U.S.
Class: |
417/33;
200/61.45R; 415/199.1; 417/44.1; 192/129A; 415/160 |
Current CPC
Class: |
F01D
21/04 (20130101); F04D 27/0292 (20130101) |
Current International
Class: |
F04D
27/02 (20060101); F01D 21/00 (20060101); F01D
21/04 (20060101); F04b 049/02 () |
Field of
Search: |
;417/1,33,44 ;308/1.5
;184/6.4 ;200/61.45R ;192/129A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Croyle; Carlton R.
Assistant Examiner: Sher; R. J.
Claims
We claim:
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.
Description
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
The impellers 10, 11 are mounted on an impeller drive shaft 12. The
shaft 12 is journaled in bearings mounted in a casing having upper
and lower sections 13, 14 detachably secured together as by bolts
15, see FIG. 1. A driver 17 as an electric motor, steam turbine or
the like is operatively connected to the impeller shaft 12 to
effect rotation thereof.
Control circuitry is provided for the driver 17 and includes a
control element 20 connected by line 21 to the contacts of a switch
23. When the contacts of the switch 23 are actuated, the control
element functions to deenergize the driver 17.
A lug 26 is formed on the inner surface of the top casing section
13. A bracket 27 is mounted on the lug 26 as by bolts 29. The
bracket 27 is of right angle form in cross section having side
flanges 30, 31. The flange 31 is formed with elongated apertures 35
through which the mounting bolts 29 extend. With this arrangement,
the bracket 27 may be adjusted toward and from the impeller drive
shaft 12.
The switch 23 is fixed to the flange 31 of the bracket, as by
screws 40, and is constructed with a contact actuating plunger 43
extending through an aperture 44 in the flange 30 of the bracket
27.
A lever 45 is pivotally mounted intermediate its ends to the flange
30 by bolt 47. As the lever 45 is moved about its pivot 47, one end
of the driver is moved in to and out of engagement with the plunger
43. The surface of the lever contacting the plunger 43 is formed
with a depression 50. The plunger 43 is spring pressed outwardly
and when the outer end of the plunger is seated in the recess 50,
the lever 45 is yieldingly restrained against movement about the
pivot 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 the impeller shaft 12.
The impeller shaft 12 is provided with a projection 51 located to
engage the free end of the lever 45 upon the impeller shaft
shifting axially or radially from normal operating position. Upon
the projection 51 engaging the lever 45, it is moved from the
dotted line position in FIG. 3 to the full line position.
Accordingly, the opposite end of the lever 45 is moved out of
engagement with the plunger 43. The movement of the spring press
plunger is such that a substantial end portion of the plunger
extends outwardly from the flange 30 of the bracket, as shown in
FIG. 4, and serves to prevent return movement of the lever 45. That
is, when the lever 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 the projection 51 moves, the path being
indicated by the line 53. This is advantageous in that it prevents
the projection 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 the shaft 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.
* * * * *