US1796796A - Compressor unloader - Google Patents

Description

COMPRES SOB UNLOADER Filed Sept. 14, 1929 IN VENTOR.

H15 ATTORNEY.

Patented Mar. 17,193]

UNITED STATES PATENT OFFICE JOHN LE VALLEY, on PAINTED rosr,

NEW YORK, ASSIGNOR T INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY COMBR-ESSOR UNLOADER Application filed September 14, 1929. Serial No. 392,695.

This invention relates to compressors, but more particularly to a compressor unloader adapted to automatically unseat the inlet valve or valves of compressors whenever the pressure in the receiver into which the compressor discharges reaches a certain predetermined value.

One object of the invention is to prevent communication between the cylinder of the compressor and the channels through which air is conveyed to the cylinder.

Another object is to protect the unloadcr and cooperating elements against severe jars or strains by suitable cushioningmcans which Will-yield gradually to the pressure for actuating the unloader.

Other objects will be in part obvious and in part pointed out. hereinafter-a The figure in the accompanying drawin is applied a sectional elevation of a compressor unloader constructed in accordance with the practice of-the invention and showing the unloader applied to a compressor.

Referring more particularly to the drawing, A represents: a portion of a compressor cylinder having a compressor chamber B in which is disposed a piston C. A. closure is provided for the compressor chamber 13 by a head I) which may be secured to the cylinder in any suitable and convenient manner.

The cylinder A comprises an inner wall E and an outer wall F spaced with respect to the wall E to to m therebetween a passage G through which air, either compressed air from a lower sta e c linder or atmos )heric air, may flow to the compressor chamber B.

The walls E and F are provided With aper tures H and J respectively which are aranged coaxially with respect to each other.

The aperture H is adapted to accommodate valve mechanism designated generally by K, and comprising a valve seat L which seats against the wall E and in this instance has seating surfaces 0 and P at opposite ends. In the valve seat L is a port or ports Q through which the air from the passage G on ters the compressor chamber B. The outlet end B of the port Q is controlled in this instance by a valve plate S which cooperates With the seating surface 0 for this purpose and is urged thereagainst by a spring T interposed between the valve plate S and a stop plate U which may be secured to the valve seat in any suitable manner, as by a bolt W and a nut X In order to conveniently hold the valve assembly in the aperture H an unloader cylinder Y is threaded into the aperture J and said unloader cylinder carries at its inner end a skirt Z adapted to bear against the valve seat L. In this skirt are formed ports I) to afford free communication. between the passage G and the port Q, in the valve seat,

In addition to the function described, the unloaded. cylinder Y also serves as a housing for unloading devices intended to selectively cut oil communication between the port Q and the passage G. To this end the cylinder Y is provided with a bore 0 to slidably receive a hollow plunger d. The bore 0 extends entirely through the unloader cylinder Y, although the inner portion, that is, the portion adjacent the skirt Z is of somewhat reduced diameter as at e to accommodate a reduced extension f of the plunger (Z. In this way is formed a shoulder g in the bore 0 which may act as a stop for a shoulder it on the plunger (Z in order to assure the retention of the plunger in the bore, particularly during the assembly of the device in the compressor.

Secured to the outer end of the unloader cylinder, as by means of bolts j, is a cover I: which forms a closure for the bore 0, and said cover it is n'eferably provided with a cavity 0 to serve as a chamber into which pressure fluid from a suitable source of supply may be introduced into the end of the bore 0 for depressing the plunger (Z. For this purpose a pipe 1] is threaded into the cover is.

The cavity Q in the plunger (Z is adapted to accommodate slidably a valve 1* of cup shape having a hollow body portion .5- and at its open end a lateral flange t to cooperate with the seating surface P for closing the inlet end oi the port Q In order to normally assure the retractul positions of the plunger (Z and the valve 7*, a spring o is disposed Within the plunger (3 to bear against the end of the valve 1", and a spring w is interposed between the valve seat L and the valve 1".

Any suitable and well known means, as for instance, an auxiliary valve (not shown) may be interposed in the pipe p for automatically controlling the admission of pressure fluid into thechamberro, when the receiver pressure exceeds a certain predetermined value, and to automatically exhaust such pressure fluid from the chamber 0 after the pressure in the storage receiver has again dropped below that which it is desired to maintain.

During the normal operation of the comoressor, as when the compressor is operating under full load conditions,'the plunger cl and the valve 1" will beheld in the retracted position by the springs '12 and w. Air will then flow from the passage G through the port Q and into the chamber B where it will be compressed by the piston C. This operation may continue until the pressure in the storage receiver into which the compressor discharges reaches a maximum value which it is desired to maintain therein and at which such controllingdevices as may be interposed in the pipe p are adapted to act for unloading the compressor.

Whenever this pressure has been attained, pressure fluid will be admitted into the pressure chamber 0 to act against the plunger cl. and to move the plunger in the direction of the valve assembly. The movement of the plunger will be transmitted through the spring oto the valve 1" and the spring w will then also act to resist the movement, of the plunger as well as the movement of the valve 7. The plunger and the valve will however be moved inwardly until the flange 27 seats against the seating surface P to close the inlet opening of the valve may be reached withoutcompressing the spring 0 to such an extentwhere the innermost end of the reduced portion f of the plunger will contact with the flange t, depending, of course, upon the tension of the spring o. The plunger may however be pressed into body contact with the flange t to hold the valve r in the closed position until the receiver pressure has again been decreased below the maximum pressure at which the unloader is intended to act. When this condition in the receiver obtains the means provided for automatically releasing the pres sure fluid in the chamber 0 may then act and the plunger cl and the valve 4 will a ain be restored to the retracted positionsdoy the springs acting thereagainst.

I claim: a

1. A compressor unloader, comprising a valve seat having a port, a valve plate for controlling one end of theport, an unloader ed plunger therein,

cylinder over the valve seat, a pressure actuata valve slidable in the plungerv and adapted to seat over the other port Q. This pressure of the end of the port, and a spring between the plunger and the valve for transmitting the movement of the plunger to the lastsaid valve.

2. A. compressor unloader, comprising a valve seat having a port, a valve plate for controlling the outlet end of the port, an unloader cylinder over the valve seat, a pressure actuated plunger therein, a valve slidable in the plunger and adapted to seat'over the inlet end of the port, and a spring between the plunger and valve for causing the last said valve to follow the movement of the plunger.

3. A compressor unloader, comprising a valve seat having a'port, a valve plate for controlling the outlet end of the port, an unloader cylinder over the valve seat, a pressure actuated plunger therein, a valve slid able in the'plunger and havinga flange adapted to seat over the inlet end of the port, a spring between the plunger and valve for transmitting the movement of the plunger to the last said valve, and a second spring between the valve plate and the valve to normally maintainfthe valve free. from the valve seat. v

4. A compressor unloader, comprising a valve seat having a port, a'valve plate for controlling the outlet end of the port, an unloader cylinder over the valve seat, a pressure actuated plunger therein, a cup-shaped valve slidable in the plunger and having a flange at its open end adapted to seat over the inlet end of the port, a spring in the plunger abutting the closed end of the valve for transmitting the movement of the plunger to the last said valve, and a second spring positioned in the cup-shaped valve and abutting the valve plate to normally maintain the valve free from the valveseat In testimony whereof I have signed this specification. v T

JOHN LE VALLEY.

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