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Патент USA US2112564

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March 29,1938.
Filed NOV. 11, 1935
2 Sheets-Sheet l _
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March 29, 1938. K
Filed Nov. 11,1935"
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Patented Mai-.29, 1938
' 2,112,564
V. Haight, Ashton-on-Mersey, England;
asslgnor to Ingerso
-Rand Company,
City, N. J., a corporation of New JerseyJersey
Application ‘November’ 11, 1935, Serial‘ No. 49,207
1 Claim. (Cl. 230-29)
This invention relates to compressors, but more
particularly to an unloader fo'r compressors .of daubuiar member 32 of which the interior or pas
sage 33 serves to convey ?uid from the manifold.
the multi-stage type.
‘ The'tubuiar member 32 supports a valve'mech-,
anism 34 of which a casing 35 is threadedly con
nected to an intermediate portion of the tubular _ 5
member. The lower end 36 of the member 32
projects into a chamber 31 in the casing 35, and
in the side of the chamber 31. is an outlet-open
Other objectsv will be in part obvious and in
Part pointed out hereinafter. .
In the drawings accompanying this. speci?ca
tion and in which similar reference numerals
The casing 35 consists of an upper section 33
Figure 1_' is an end elevation of a compressor
threaded to the tubular member 32 and a lower
section 40 secured to the section 39, as by bolts
refer to similar parts,
equipped with'an unloader constructed in ac
cordance with the practice of the invention,
Figure 2 is a side elevation of the compressor
partly broken away. and
ing, illustrated as being in the form of a con
‘duit 33, which may open directly to the atmos- 10
Dhere-or to a source of ?uid medium.
Figure 3 is an elevation, in section, of the un
4|. A ?exible diaphragm 42 is clamped between 15
the casing sections to seal the chamber 31 from
a chamber 43 in the casing section“.
The diaphragm 42, which may be capable of a
considerable degree of movement in the casing
35, carries avalve v44 to control the outlet opening 20
of the passage 33. The valve is secured to the
diaphragm by a bolt 45.
It is arranged in a .
plate 46 upon which-is seated‘a spring 4‘! ar
ranged about the lower end 36 ‘of the tubular 4
member to open the valve. On the lower surface 25
' of the diaphragm is a plate
48 which is clamped
to the diaphragm by the bolt 45 and seats against
a hollow boss 49 in the chamber 43 for limiting
the opening movement of thevalve 44.
The surface of the diaphragm confronting the 30 '
chamber 43 constitutes a pressure surface 53
which is subjected to pressure ?uid admitted to .
the pressure chamber 43 directly from the high
- pressure cylinder 23.
Such pressure ?uid is con
veyed to the chamber 43 by a conduit 5| which 35
communicates constantly with the upper'end of
the high pressure cylinder 23 through a passage‘
52 and with the chamber 43 through a port 53.
Thus, in operation, pressure ?uid may ?ow di
rectly from the high pressure cylinder 23 through 40
the conduit 5| into the chamber 43 and act
Upon being compressed to a higher against the pressure surface. 50 for holding the
46 pressure in the latter cylinder the ?uid passes ,valve'44 in sealing relationship with the outlet
‘through a discharge conduit 33 into a storage re ' opening of the tubular member 32 vto normally ~
prevent the ?ow oi’. the lower stage discharge 45
In accordance with the present invention, pressure to the atmosphere.
means are provided for relieving the motor‘26
In order, however, to assure the retention of a
ceiver 3|.
L50 from the strain of starting the compressor when
suitable pressure in the
returning to the high
pressure cylinder 23 during the suction stroke of
its piston v24. The, conduit 5| is accordingly
provided with a. delay valve mechanism 54 com- 55 p
prising a casing '55 into the ends of which are
threaded sections- of the conduit 5|.
Within the casing 55 are a pair of passages
56 and 51 of which the passage 5iv is in direct
communication with a portion of the conduit Bl
connected to the chamber 43, and the passage 51
communicates directly with the conduit leading to
If then the compressor be set in operation the
inter-cooler will remain completely unloaded, and
the ?uid medium entering the high pressure cyl
inder may escape through the conduit ii, the
valve cage 61 and through the port 69 to its
source. The compressor will continue to operate
in this wise until its speed approaches or reaches
normal, at which time the centrifugal action of
the weight 13, retracts the plunger ‘Ill and the
the high pressure cylinder 23. The passages 56
and 51 communicate with each other through
ball valve 63 will then‘close the port 69 to pre
10 ports 58 and 59.
The function of the port 58
-is that ofa discharge port for the passage 51
vent further passage of ?uid to the atmosphere.
Thereafter, the ?uid compressed in the high
and said‘ port is controlled by a check valve 80
arranged in a recess 6| at'the outlet end of the
pressure cylinder 23 ?ows through the conduit
II, passage 51, port 58 and the passage 56 into
the chamber 42 and shifts the valve 44 into seal
port 5l._ The opening movement of the valve 60
is resisted by a_ spring 62 extending into and» ing relationship with the end of the tubular 1
guided by a bushing 63 threaded into the cas
member‘ 32. The manifold and inter-cooler will
The-port 59 serves as a'
passage 56.
' then be closed and the ?uid compressed by-the
discharge, port for the low pressure cylinder passes to the high pressure
Its inlet end is in the form of .a I cylinder where it is compressed to a higher value 20
and discharged into the receiver 8|.
20 tapered portion 64 to conform to the end of a
needle valve 65 extending thereinto to de?ne the
?ow area of the port 59.
The needle valve is
threaded into the casing 55 and lockedin posi
tion, in the present instance,‘ by a cap nut 66
During this operation of the compressor the
?uid employed for holding the valve 44 seated
against the member 32 will be prevented from
returning to the high pressure cylinder 23 by 25
whichseats against'the side of the casing 55 to the needle valve “which will be so adjusted as
prevent loss ‘of pressure v?uid along the threads , to allow only a very considerably restricted ?ow
of the needle valve to the atmosphere. '
of pressure ?uid through the port 59.
Any suitable means may be employedfor vent- ,
when the compressor again ceases operating
--ing the conduit 5| to the atmosphere or a source the spring 12 actuates the plunger ‘I. and unseats
30 of ?uid medium in order to provide an escape the ball valve ‘3, The high pressure cylinder
for pressure ?uid from the chamber 43 and from will then again be communicated with'the atmos- _
the cylinder 23 at the end of an operating period phere, and the pressure ?uidin the chamber 43
in order to relieve the compressor of its load for employed for holding the valve I‘ closed ?ows
a subsequent period of operation. The means from the chamber 43 through the passage 56, 35
illustrated for this. purpose comprises a valve the space defined by the needle valve and the
35 cage 61 to which is connected a branch of the portion 84, thence through the valve cage 61 to
conduit 5i and containing a ball valve SI for the atmosphereto again completely unload the‘ '_
controlling a discharge port 09 in the valve cage. inter-cooler and also the high pressure cylinder
The valve cage is preferably arranged concen
trically with respect to the crank shaft 25 of the
' compressor and in the end of the drive shaft is
. a plunger ‘Ill having a reduced projection ‘ll
23 preparatory to another period of operation. . 40
I claim:
A starting unloader for a compressor having
I a cylinder operating-ata low pressure and a cyl
“which extends loosely into the port 69 to unseat inder operating‘at a higher pressure, an inter-_
10 is actuated,
the ball valve '8. The plunger
45 to perform this function, by a‘ spring 12 and is
‘ normally held in retracted position by centrifu
gal weights 13 mounted on pivots 14 carried by
the crank shaft 25.
The operation of ‘the device is ‘as follows:
Let .~
- it be assumed that the compressor is at rest and
that‘the plunger ‘III is then actuated, by the spring
12 to unseat the valve 68.
With the ball valve
in this position the high pressure cylinder 23
' and the chamber 43 will be in direct communi
cation with the atmosphere.
The valve 44 will
cooler between the cylinders and having an at
mospheric vent, a pressure actuated valve to con
trol the vent, a conduit leading from the high
pressure cylinder on the cylinder side of the
discharge valve thereof to the valve and being ‘
in constant communication with the high pres 50
sure cylinder,‘ means in the conduit between the
high pressure cylinder and the inter-cooler for
venting the valve and the high pressure cylinder
to the atmosphere for unloading the compressor,
and means between the venting means and the -
valve for restricting the ?ow of pressurei?uid
then be held in its open position by‘ the spring ' ' from the valve to the venting means while per
41, and the chambers and passages between the
discharge side of the low pressure oylindervand
the inlet side of the high pressure cylinder 'will
60 also be in direct communication with the atmos
mitting free ?ow offluid from the high pressure
cylinder to the valve.
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