US2172751A - Compressor - Google Patents

Description

J. HEINRICH sept. 12, 1939.

C OMPRES S 0R Filed May 25, 1938 2 Sheets-SheetA 1 INVENTOR JOHANN HE/NR/CH l B ATTORNEYS J. HEINRICH Sept. l2, 1939.

coMPREssoR Filed may 25, 1938 2 Sheets-Sheet 2 Patented Sept. 12, 1939 UNITED STATES PATENT OFFICE coMrnEsson Application May 25;'i93a'fs'ri1N0. 269,939

In Germany Juiylz, 1937 s claims. (c1. 23o-s1) This invention relates to compressors and refers more particularly to devices for regulating gradually and without steps the amount of the medium compressed by compressors the suction valves of whichare carried by theirpistons.

In compressors of a different type wherein thev suction valves are situated upon the side walls or the cover of the main cylinder; the regulation of the amount of the compressed Kmedium may be carried out by keeping the suction valve open during a part of the compression stroke; then a. portion -of the medium is removed through thej, suction valve while only a predetermined amount 4 of the medium is compressed by the main piston of the compressor. The opening and closing of the suction valve is caused by an auxiliary piston which is movable within an auxiliary cylinder and which may be actuated by the medium which has been compressed during the previous vcompression stroke. 'Ihe medium which exerts its pressure upon the auxiliarypiston can return gradually to the cylinder by means of a by-pass with the result that the pressure upon the auxiliary piston drops gradually until it becomes smaller than the pressure exertedupon the suction valve by the medium situated within the main cylinder of the compressor during the following compression stroke. This causes the closing of the suction valve. Ihen` the medium remaining in the main cylinder is compressed to the final pressure.

This procedure cannot be used in compressors the suction valves of which are carried by the main pistons and wherein the medium ows in the same vdirection through the main cylinder from the suction valve to the outflow valve carried by the cover of the cylinder, since suction valves of this type cannot be operated in the described manner.

An object of the present invention is to adapt the described procedure to so-called uniform iiow compressors, used particularly in refrigerating plants, a -characteristic feature of which is the arrangement of -the suction valves upon the main pistons.

Another object isthe provision of nrieans'whichregulate the amount of the medium compressed by a uniform iiow compressor in such manner that the gaseous cooling medium removed from the evaporator is not heated excessively when it is introduced into the main cylinder, thereby avoiding a drop in the efficiency of the compressor.

A further object is the provision of means for lating valve. pressed by the compressor depends upon the mo- 'ment'of closing of the auxiliary valve which is,

4 regulating the amount of the compressed medium in cooling plants in conformity with the desired output of the evaporator..

Other objects of the present invention will be apparent in the course of the following speci- 5 cation.

The objects lof the present invention may be realized through the provision of an auxiliary valve which is carried by the side walls of the cylinder close to its cover and which is connected with an auxiliary circuit provided with a regu- The amount of the medium comdeterminedv by the 4adjustment of the regulat- 15 ing valve. When the auxiliary valve isopen, it connects the interior of the main cylinder with a chamber which is provided in the casing of the main cylinder and which is in communication with the main suction conduit. 20

The auxiliary valve is so located that it is not covered by the main piston in the upper dead end position of the latter, since otherwise it would not be possible to regulate the compressor when itis running without performing any substantial useful work.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example preferred embodiments of the inventive idea.

In the drawings:

Figure 1 is a vertical section through a uniformflow compressor constructed in accordance with the principles of the present invention; 35

Figure 2 is a section 'througha compressor of a 'somewhat diiferent type; land 'cylinder I.

'I'he medium to be compressed is introduced into the cylinder through a passage or suction 5 0.

conduit 52 which is in communicationv with an annular suction chamber I3.V The compressed i Y medium ows through the openings 58 of the valve 4 into a chamber 53 and is removed through the passage 54.

of the cylinder I and a return-flow chamber I5 which is in communication with the suctionv chamber I3.

One end of a conduit 8 is in communication with the interior of the cylinder I directly underneath the valve 4. The other end of the conduit 8 is in communication with the interior of the auxiliary cylinder 1. The conduit 8 carries a non-return valve 9, which is situated intermediate its ends. An auxiliary conduit III, which carries a manually adjustable throttle valve I2, is in communication with the conduit 8 onboth sides of the non-return valve 9.

The device operates as follows:

During the compression stroke of the piston 2, a part of the compressed medium flows through the conduit 8 and through the non-return valve 9 into the auxiliary cylinder 1. Although this compressed medium will exert a pressure upon the auxiliary piston 6, it will not be .able to open the valve 5 at that time, since the pressure of the compressed medium acting upon the larger surface of the valve 5 will be greater than that exerted upon the piston 6.

In the course of the=followlng suction stroken-.r the pressure will drop within the main cylinder I.Y

Although the compressed medium within the cylinder 1- will not be able to return through the non-return valve 9, it will be -able to flow around the valve 9 through the auxiliary conduit I Ii which is provided with the throttle valve I2. The amount of the returning compressed medium, and

therefore the rate of the drop in pressure withinI the auxiliary cylinder 1, can-be easily regulated by adjusting by hand the throttle valve I2.

In view of the drop in pressure within the maincylinder I, lthecompressed medium remainingin the cylinder 1 will move the piston 6 and open the valve 5.

When the piston 2 stroke and begins its next compression'stroke, the valve 5 will remain open for a predetermined period of time until the increase in pressure within the cylinder I will cause the closing of the valve 5.

While the valve 5 remains open, a portion of the medium within the cylinder I flows through the passage 51 of the valve 5 into the chamber I5 of the cylinder I. After the closing of the valve 5, which is due to the increase in .pressure within the cylinder I, the medium remaining within the cylinder is compressed to its final pressure and causes the outow valve 4 to open. Then the compressed medium flows through the passages 58 of the valve 4 into the chamber 53 and is removed through the conduit 54.

While the valve 5 remains open, th'e medium flowing through the passage 51 into the chamber I5, passes into the suction chamber I3, vso that it can return to the interior of the cylinder I during the next suction stroke of the piston.

The compressor illustrated in Figure 2 is provided with a main piston 59, which' carries a suction valve26. A separate auxiliary valve l25 is situated adjacent the cover of the `compressor. The piston 59 is reciprocated within the main cylinder 66 and is connected by the rod 6I with the main shaft 30.

has 'I completed its I suction The auxiliary valve 25 is connected by .a connecting rod 62 with a piston 21 which is reciprocated within the auxiliary cylinder 43. Th'e piston 21 cooperates with the spring 44 which surrounds a portion of the rod 62.

The shaft 30 is carried by the main casing 28 of the compressor.

The main cylinder 60 is provided with an outilow valve 63 vand an outflow chamber 38. One

, end of the pipe 39 is connected with the chamber 38 while the opposite end of this pipe is in communication with an opening 64 formed in a cover 65.

The cover 65 is connected to a separate casing 29 which constitutes a bearing for that end of the shaft 30 which is used for regulating purposes. The casing 29 is connected to the main casing 28. The casing 29 isl provided with an opening 4I which is in communication with one end of a pipe 42. The opposite end of the pipe 42 is in communication with the interior of the auxiliary cyl- The returning compressed medium is conducted through the return-flow chamber 45 directly to the suction chamber 49 of the compressor.

This compressor is provided with' a rotary sliding device' for regulating the time of the closing of the auxiliary valve 25. Devices of this type are described in greater detail in the co-pending patent application, Serial No. 209,938, filed May 25, 1938, for Compressors.

As shown in Figure 3, the shaft 30 is provided with an axial passage 3|, one end of which is connected with a radial passage or bore-hole 32 extending at right angles to the passage 3|. A regulating sleeve 34 encloses this portion of the shaft 30 and is carriedby the casing 29.

u The space 66 between the shaft 30 and the inner walls of the casing 29 is longer than the sleeve 34, so that the sleeve 34 may be moved axially within the space 66. 'I'he movement of the sleeve 34 is carried out by means of the spindle 35 and the arms 36 which engage theouter surfaces of the sleeve 34. The spindle 35 is carried by the 4 cover 65.

The operation of the device is as follows:

A portion of the compressed iluid within the chamber 38 flows through the pipe 39 into the chamber 40 enclosed by the cover 65 and fills the passage 3I and 32 formed in the shaft 30. In the position illustrated in Figure 3, the sleeve 34 interrupts the connection between the passage 32 and the opening 4I.

When the sleeve 34 is so shifted by means of the spindle 35 that its opening 31 establishes a communication between the passage 32 formed in the shaft 30 and the passage 4I formed in the casing, 29, then the compressed medium contained in the chamber 4 0 Will flow through the passages 3l and 32 of the shaft 30, theopening 31 of the sleeve 34, and the passage 4I of the casing 29, reaching the pipe 42 and the interior of the auxiliary cylinder 43. Y

lThe compressed medium'within the .cylinder 43 will move the piston 21 thereby compressing the spring 44 and opening the valve 25 to establish a connection between the interior of the cylinder 60 and the chamber 45.

The .auxiliary valve 25 is so located that it remains above the piston 59 in the upper deadend position of the piston, since otherwise it would be impossible to regulate the compressor when it is running without performing any substantial useful work.

The compressed 'medium situated within the' auxiliary cylinder 43 will gradually return through the passage 46 into the chamber 45 until the auxiliary valve 25 is closed by the increased pressure within the cylinder 60 in the course of the following compression stroke of the piston 59. l

In the position shown in Figures 2 and 3 no connection is established'between the pipesv39 and 42, so that the valve 25 does not open at all and the compressor is operated at full capacity.

If it is desired to reduce the amount of the medium compressed by the compressor, then the spindle 35 is` actuated to shift the sleeve 34 axially until the opening 31 in the sleeve 34 is placed between the opening 4I which is in communication with the pipe 42, and the passage 32 .within the shaft 30.

In the described construction, the compressed medium which has beenYremoved already from the interior of the main cylinder 60 is introduced into -the chamber 38 and the pipe`39.

Obviously, the pressure medium used for operating the piston 21 can be taken from a separate container of a compressor plant or from any other suitable source. The advantage of thus regulating the auxiliary valve 25 is that it is possible to further diminish and to regulate exactly the amount of the medium compressed by the compressor.

In order to retain the advantages of a uniform flow compressor, it is necessary that the auxiliary valve be open only at the beginning of each compression stroke and that it be closed during each suction stroke. This can be attained by making the spring 44 actuating the auxiliary'valve 25, stronger than the spring 10 actuating the suction valve 26.

It was found that when the'compressed medium is removed directly from the main cylinder, if the amount to be compressed is comparatively small, the conduits and chambers of the device are insufficiently filled with the compressed medium and the rate of the drop in pressure in the auxiliary cylinder is comparatively small. so that a comparatively long time is required to diminish that pressure to the desired extent. Since the curves representing the drop in pressure in the auxiliary cylinder 43 and the pressure acting 'upon the valve 25 are comparatively at. their point of intersection. which determines the mo- It is apparent that the specific illustrations shown above have been given by way of illustration and not by way of limitation, and that the structures above describedare subject to wide variation and modification without departing from the scope or intent of the invention, all of which variations and modifications are to be included within the scope of the present invention.

What is claimed is: 1. A regulating device for a compressor having This drawback which is parf a cylinder, a main piston reciprocable withinsaid cylinder, and a suction valve carried by said piston; said regulating device comprising a separate auxiliary valve carried by said cylinder, and means connected with said auxiliary valve for maintaining it open during a part of the compression stroke of the main piston.

2. A regulating device for a compressor having a cylinder, a main piston reciprocable within said cylinder, and a suction valve carried by said piston; said regulating device comprising a` separate auxiliaryva1ve carried by said cylinder, and being situated abovesaid piston in the course of the reciprocation of the latter, and means connected with said auxiliary valve for maintaining it open during a part of the compression stroke of the main piston.

3. A regulating device for a 'compressor having a cylinder, a main piston reciprocable within said cylinder, and a suction valve carried by said piston; said regulating device comprising a separate auxiliary valve carried by said cylinder, means supplying a pressure medium to said auxiliary valve to maintain it open during a predetermined period of time, andmeans connected with the'rst-mentioned means to regulate the pressure of said compressed medium upon said auxiliary valve, whereby the period of time during which said auxiliary valve remains open is varied.

4. A regulating'device for a compressor having a cylinder, a main piston reciprocable within said cylinder, a suction chamber being formed in said cylinder, and a suction valve carried by said piston; said regulating device comprising an auxiliary valve carried by said cylinder, means constituting a part of said cylinder and forming a return-flow chamber which is in communication with said suction chamber, and means connected with said auxiliary valve for maintaining it open during a part of the compression stroke of the main piston, a portion of the medium owing from the interior of said cylinder to said returnow chamber and said suction chamber.

5. A regulating device for a compressor having a cylinder, a main piston reciprocable Within spring, and means connected with said auxiliaryY valve for maintaining it open during a predetermined perlod of time 6. A regulating device for a compressor having a cylinder, a main piston reciprocable within said cylinder,.and a suction valve carried by said piston; said regulating device comprising an auxiliary valve carried by said cylinder, an `auxiliary cylinder constituting a portion of the rst-mentioned cylinder, an auxiliary piston connected with said auxiliary valve and reciprocable within the auxiliary cylinder, means connected wth two cylinders for supplying the medium compressed by the first-mentioned cylinder to the auxiliary piston, and regulatable means connected with the first-mentioned means for gradually reducing. the pressure of the compressed medium upon the auxiliary piston.

. '7. A regulating device for a compressor having a cylinder, a main piston reciprocable within said cylinder, and a suction valve carried by said piston; said regulating device comprising an auxiliary 'valve carried by said cylinder, an auxiliary cylinder constituting a portion of the iirst-men tioned cylinder, an auxiliary piston connected with said auxiliary valve and reciprocable within the auxiliary cylinder, conduits connected with the two cylinders for supplying the medium compressed by the iirst-mentioned cylinder to the auxiliary piston, another conduit connected with one of the mst-mentioned conduits and said cylinder and communicating with said suction chamber for gradually removing -the compressed medium from the auxiliary cylinder to the suction chamber, and a throttle valve carried by the last-mentioned conduit.

8. A regulating device for a compressor having a cylinder, a main piston reciprocable within said cylinder, and a suction valve carried by said piston; said regulating device comprising an auxiliary valve carried by said cylinder, an auxiliary cylinder constituting a portion of the iirst-mentioned cylinder, an auxiliary piston connected with said auxiliary valve and reciprocable within the auxiliary cylinder, a conduit having one end communicating with the interior of the rstmentioned cylinder and another end communi-

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