US2134958A - Refrigerant compressor - Google Patents

Description

NOV. 1, 1938. L, Q SHUHQLM 2,134,958

REFRI GERANT COMPRES SOR Filed July 23, 1937 5 Sheets-Sheet 2 INVENTOR. LESTER GSHUHOLM ATTORNEY.

Nov. 1, 1938. c. SHUHOLM V v REFRIGERANT COMPRESSOR 5 SheetsSheet 5 Filed July 25, 1957 INVENTOR. LESTER C. SHUHOLM 12M fy 'ATTORNEY.

Nov. 1, 1938. L. c. SHUHOLM REFRIGERANT COMPRES 5 OR Filed July 23, 1937 5 Sheets-Sheet 5 1 n 7 w .l //J v/////////v/ T INVENTOR. LESTER C. SHUHOLM 6 ATTORNEY.

Patented Nov. 1, 1938 REFRIGERANT- CO- Application July 23,

.6 Claims.

This invention, in its generic aspects, relates to fluid compressing machineswhich compress the fluids for the purpose of applying their expansive forces, when released from pressure, to perform the work required of them. The invention is more specifically directed to a compressing machine employed as a part of a refrigeration system.

A refrigerant compressing machine embodying the principles of my invention consists essen-.

tially of a crank shaft or a shaft having a plurality of eccentrics, a low pressure cylinder, a

high pressure cylinder, and apiston valve cylinder, pistons of graduated lengths and diameters operated in the cylinders, ports passing through ing rods joined to the eccentrics and the pistons,-

all having predetermined dimensions to provide the desired relation between them in order to operate efliciently.

The quintessence of the invention is to provide a comparatively silent, long-lived, and relatively compact refrigerant compressing machine employing single-acting pistons for compressing the fluid in two stages and by-passing the compressed 2 fluid through a piston valve. into the condensing portion of the refrigeration system, while at the same time employing one of these pistons in directing the low pressure fluid into the low pressure cylinder for the first step in the succeeding '0 cycle of the compressing operation.

As a corollary'to the above. object and equally important therewith is the complete elimination of poppet or plate type valves, which normally are the noise makers in the present type of com- -88 pression machines, and providing in lieu thereof a piston valve for the delivery act of the compressing machine and making one of thepistons perform the dual function of compressing the refrigerant and by-passing low pressure refrigerant 40 into the low pressure cylinder.

An equally important object of my invention is the provision within a compression machine of pistons adapted to compress fluids in two stages and in theposition of ports in communication 45 with the cylinders in which the pistons operate, so that the refrigerant, after'being compressed for a predetermined amount, may be delivered, under continuous compression into another cylinder for compression and may finally be discharged I from the compression machine through a piston valve in communication with one of the cylinders and delivered to the condenser under a predetermined pressure.

Another object of the invention is to permit Q only a small amount of compression within the .RESSOR I .ester C. Shuholm, Portland, Greg.

1937, Serial No. 155,232 (Cl. 230-183) low pressure cylinder in order to bring about a relatively slight increase in temperature in the refrigerant before it reaches the high pressure cylinder.

Another important object of my invention may be found in providing an interrrelation and continuation of ports in a compressing machine for permitting its operation at high speeds without appreciably reducing its volumetric efliciency, but, in fact, noticeably increasing its displacement, and which .allows corresponding reduction in the size of the compressing machine resulting in a corresponding reduction in cost of manufacture,installation, and operation.

Other objects and advantages of my invention will become apparent from the following detailed a description which must be read in conjunction with the accompanying drawings, illustrating, by way of example, the preferred design and construction by which my invention may be put into practice.

In the draw ngs: 1

Figure 1 is a side elevation of a compressor embodying the principles of my invention, parts of which are broken away to show, in cross section, the shaft housing, the cylinders, and the pistons. Figure 2 is an end elevation of the machine shown in Figure 1, partially in section and partially broken away, to show, in cross section, the cylinders and pistons and also the relationship of some of the ports to the cylinders.

Figure 3 is a sectional, top view, taken on line 3-3 of Figure 1, looking in the direction indicated, showing the relative position of the cylinders with respect to each other.

Figure 4 is a sectional, top view, taken on line 4-4 of Figure 5, looking in the direction indicated, graphically illustrating the intake passageway surrounding the low pressure cylinder.

Figure '5 is a sectional elevation, taken on line 5-5 of Figure 3, looking in the direction indicated, of the compressing machine embodying the principles of my invention, illustrating the structural characteristics of the cylinders and pistons and the relationship between the various portsto the pistons, the cylinders, and to each other.

Figure 6 is a plan view showing the cylinderblock coverplate or head.

Figures 7 to 14 inclusive are semi-diagrammatic views of the cylinders and pistons embodying the principles of my invention, looking from the valve cylinder end of the compressing machine, graphically illustrating the positions the pistons assume during the various stages in a complete -compression cycle of operation and illustrating the relative importance of the positions of the ports and pistons for the efficient operation of a compression machine embodying the principles of my invention.

In the several views of the drawings, like reference characters are employed in referring to identical parts.

In Figures 1 and 2 is shown the casing or shaft housing and related assembly which is generally designated by reference character A. Since, in most instances, electricity will be the source of power, it may be assumed that housing exemplifies the casing of an electric motor from which shaft 2 extends. A compressor embodying the present invention may be made to operate at a shaft of the source of power, it is of course ob.--

vious that shaft 2 may be made independent from the shaft of the source of power but suitablysecured thereto. Housing I is held against shaft housing 3 by any desirable means as by a bolt and nut connection as shown by reference numeral 4, The manner of mounting shaft 2 in shaft housing 3 is clearly shown in Figure .1 wherein suitable bearings 5 and 6 support the shaft within theshaft housing.

A cylinder block or casing is superimposed and removably secured to the top of the shaft housing 3 by any desirable means as by the means shown by reference numeral 8. Incorporated within the cylinder block or casing and in communication with the interior of the shaft housing 3 are a low pressure cylinder 9, a high pressure cylinder l0 and a valve cylinder The low pressure cylinder 9 is positioned with respect to shaft 2 so that its axis is offset laterally on one side of the axis of said shaft; the high pressure cylinder I0 is positioned with respect 'to shaft 2 so that its axis is offset laterally on the other side of the axis of said shaft; and the valve piston cylinder II is positioned with respect to shaft 2 so that its axis is in alignment with and intersects the axis of said shaft. This axial relationship between the shaft and the cylinders is graphically shown in Figures 1 and 2. The reason for and advantages derived from this arrangement will be pointed out later. The cylinders have other structural characteristics which will be more fully described shortly.

The cylinder block or casing-1 isprovided with a cylinder block cover plate l2 equipped with cooling flanges l3. Additional cooling flanges M are formed around the upper portion of the cylinder block or casing I. The low pressure cylinder 9 and the high pressure cylinder III are equipped with cylinder heads I5 and I6 respectively, their position being graphically shown in Figure 5. It will be seen from Figure 5 that, in comparison with the size and position assumed by cylinder head ||i in cylinder in, cylinder head i5 is larger and enters into cylinder9 for a greater distance. These heads are spaced from the cylinderblock cover plate l2 and yieldingly held in place within the respective cylinders by the compressed resilient members I1 and I8 respectively. This mode of construction and assembly efiectively serves to' prevent any damage to the cylinders or pistons operating therein in case any non-compressible matter finds its way between the cylinder heads and the pistons, hereafter to be fully described.

A piston I9 is reciprocably disposed within the low pressure cylinder 9; another piston 29, having a hollow chamber 20A within itself, is reciprocably disposed within the high pressure cylinder I0; and a piston valve 2| is reciprocably disposed within the piston valve cylinder I I. The low and high pressure cylinders and their respective pistons act to compress the refrigerant in two stages of compression, and the valve cylinder and its piston'valve serve to deliver this fully compressed refrigerant to the condensing side of the refrigeration system.

Attention is now directed. to eccentrics 22, 23, and 24 which may be removably secured to or made an integral part of shaft 2. It is well to point out at this time that the shaft may possess therein the desired number of cranks instead of eccentrics in order to perform the work intended without departing from the invention. The size and position of the eccentrics upon the shaft are completely controlled by the strokes intended to be made by the respective pistons, as well as their timing. Eccentries 22 and 23 are positioned on the shaft so that the angular relations of their axes with relation to the axis of the shaft are partially opposed to each other and are controlled by the timing desired in the operation of a compressing machine embodying the invention.

Adjustment for eccentric 24 is provided by the use of an eccentric cam flange 25 shown in Figure l'in full line and in Figure 2 in dotted line. Extending through flange 25 and passing through slots 26 and 21 formed in eccentric 24 are bolts and nut assemblies 28 and 29. By this means the angular position of the eccentric 24 upon the shaft 2'may be readily adjusted. This simple means of adjusting the eccentric 24 on the flange 25 is merely illustrative and should not be considered as limitational.

Eccentric collars 39, 3|, and 32 are revolvably secured to eccentrics 22, 23, and 24 respectively. Secured'to these collars, are connecting rods, 34, and 35 respectively. Connecting rod 35 is made of two parts which are threadably engageable with each other for providing vertical adjustment between them. Some other method of providing this adjustment may, however, beutilized without departing from the invention. ,Con-

necting rod 33 is operatively connected to piston l9 through the medium of piston pin 35 which is mounted in bosses 31. Connecting rod 34 is operatively connected to piston 20 through the medium'of a piston pin, not shown, which is mounted in bosses 39. Connecting rod 35 is operatively connected to piston valve 2| through the medium of a ball and socket joint 35A embodying standard construction. By providing this type of connection between piston valve 2| and connecting rod 35 greater facility in making any desired adjustment is provided.

A chamber or inlet passageway 39 surrounds the greater portion of the low pressure cylinder 9 and communicates with the interior of said cylinder, as best shown at 40, in Figures 1 and 2, permitting the intake of low pressure refrigerant into cylinder 9. A refrigerant intake pipe 4|, leading from the evaporator in a refrigeration system (not shown) is secured to and communicates with the chamber or inlet passageway 39. The refrigerant is directed from the chamber or inlet passageway 39 toward the interior of the low pressure cylinder 9.

A port 42 passes through the complementary wall 43 disposed between the low pressure cylinder 9 and the high pressure cylinder I9 and connects the top portion of cylinder 9 with the substantially middle section of cylinder ID. A discharge port 44 is provided at the top of the high pressure cylinder l0 and communicates with and 4 leads into the valve cylinder II. This port is opened and closed by the piston valve 2|. The high pressure cylinder I0 is provided with an auxiliary inlet port 45 substantially midway between the top and bottom of the cylinder which communicates with passageway 39. The auxiliary inlet port 45 formed in the high pressure cylinder is arranged to coincide with a like port 46 formed substantially midway between th top and bottom portion of the piston 20, when the piston arrives at a predetermined location during its reciprocation. This intermittent alignment between the auxiliary inlet port 45 and port 46 assures the periodic communication between chamber 39 and chamber 20A found within piston 20. An outlet port 47 is arranged substantially near the top of the piston 20 for operative communication withport 42. When these two ports meet, the low pressure gas, which has previously entered into the chamber 20A in piston 20 through ports .45

and 46 by virtue of the periodic communication between chambers 39 and 20A as pointed out before, is admitted into low pressure cylinder 9.

The various relationships between the ports heretofore referred to may best be seen by an examination of Figure 5 and may be obtained from the mode of operation hereafter to be related.

A discharge or delivery pipe 48 communicates with and leads from the top of valve cylinder II and passes through the cylinder block eoverplate l2. This pipe carries the fully compressed refrigerant to the condenser (not shown).

Modus operandi This completes the detailed description of the invention as'embodied in the drawings. However, in order to more fully explain the operation of a compressing machine embodying the principles of my invention, it is well to give detailed analysis of the sequences of operation and, as an aid to the full understanding of this invention, there are presented eight views in the drawings, covered by Figures '7 to 14 inclusive, which should be referred to and examined in connection with the following analysis of the mode of operation:

The eight diagrammatic views show the relative positions the pistons-assume at different portions of their respective strokes. Furthermore, they graphically point out the degree of circular motion of the eccentrics in relation to the reciprocation of the pistons, secured by having the center lines of cylinders 9 and Ill offset from the axis of the shaft 2.

In Figures 7 to 14 inclusive, curved shaft arrows indicate the direction of the rotation of the eccentrics 22, 23, and 24 as counter-clockwise. These eccentrics are connectedto pistons I9, 20, and 2| respectively by the connecting rods 33, 34, and 35, shown by dash and double-dotted center lines.

In order that a full understanding of the operation of a compressing machine embodying my invention may be had from the views covered by Figures '7 to 14 inclusive, the ports and their relation are shown either in full or dotted line even where these ports cannot actually be seen in the views as depicted. I

It will be assumed that the cycleof operation begins with the piston l9 substantially at the bottom of its stroke as shown 'in Figure 7. When piston |9 is'in the position shown in Figure 7,

piston 20 has begun its downward stroke and piston valve 2| is about half way on its upward stroke, having previously sealed port 44. The relative positions of the pistonswith relation to the various ports and to each other, as shown in Figure '7, indicates that piston l9 has uncovered its upward stroke and has covered port 40 and is now in a position to compress the trapped refrigerant in piston 9. Piston 20 has progressed sufficiently on its downward stroke to permit ports 45 and 46 to communicate sufliciently to allow the entrance into chamber 20A of low pressure refrigerant from passageway 39 and has previously sealed port 42 before port 40 has been closed by piston I9, and finally piston valve 2| has about reached the limit of its upward stroke.

When the cycle of operation has reached the position shown in Figure 9, piston l9 has progressed sufliciently within cylinder 9 to have compressed in some degree the trapped refrigerant, while piston 20 has moved downwardly within cylinder III to have exposed port 42 sufliciently to permit the refrigerant heretofore compressed in cylinder 9 by piston Hi to enter into cylinder I6, and the piston valve I has reached the highestpoint in its stroke. It is to be noted that the major part of the partially compressed refrigerant is now to be transferred to high pressure cylinder l0 and that very little compressing takes place during and between the two stages in the cycle of operation shown in Figures 9 and 10.

When the cycle of operation has reached the position shown in Figure 10, piston i9 is completing its upward stroke; while, at the same time, piston 20 has reached the bottom of its stroke and has completely uncovered port 42, so that the compressed refrigerant enters cylinder l0 unimpeded. In this stage of the operation the piston valve H has started its downward stroke. Continuing the cycle of operation, it may be .seen from Figure 11 that piston 9 has reached the top of its stroke and piston 20 has advanced sufficiently on its upward stroke-to completely close port 42 and that the closing of port 42 by piston 26 occurs before piston l9 has made any appreciable progress on its downward stroke.

, The piston valve 2| has progressed on its downstages in the cycle of operation illustrated in Figures '7 to 11.inc1usive, the port 44 was at all times retained in a sealed condition by the piston valve 2|. It is only after the stage in the cycle of operation reached as illustrated in Figure 12, that port 44 is first unsealed .by the downward progression of the piston valve 2|. this stage of the cycle of operation, the piston i9 has made some progress on its downward stroke while the piston 20 has progressed towards the completion ofv its upward stroke sumciently to have compressed the refrigerant to a predetermined pressure normally equal to the pressure sealed.

During- In Figure 13 the progression and retrogression of the various pistons is shown more fully advanced. It will be seen that piston '20 has progressed on its upward stroke to a point which permits a portion of port 42 to coincide with a portion of port 41, thus permitting the inflow of refrigerant into cylinder 9 from chamber 20A before piston l9 has traveled any great distance on its downward stroke. Piston valve 2| has traveled downwardly sufiiciently to nearly completely unseal port 44 through which the fully compressed refrigerant is now passing.

In Figure 14 is depicted the position of the various pistons when one cycle of operation has been nearly completed. In this figure, piston I9 is about to reach the limit of its downward stroke and uncover port 40. Piston 20 has reached the limit of its upward stroke and has heretofore driven the fully compressed refrigerant into cylinder ll through port 44, and piston valve 2| is now engaged in completing the sealing of port 44 before piston 20 will have dropped appreciably in its downward stroke. This view also graphically shows that no gas can now enter into chamber 20A through ports 45 and 46 since this passage is closed; but the gas heretofore trapped within chamber 20A has been delivered into cylinder 9, and piston I9 is about to unseal port 40 in order to admit more gas from inlet passageway 39 to complement the gas already drawn into cylinder 9 by the good oflices of chamber 20A formed in piston 20.

It will be seen that by having the axes of cylinders 9 and I offset laterally on the opposite sides of the shaft and therefore not intersecting the center line of the driving shaft, a relationship is established between the circular motion of the driving eccentrics and the rectilinear mo- .tion of the pistons which provides the relationship absolutely necessary to produce theparticular sequence of timing the opening and closing of the ports, without which timing the invention as contemplated could not operate,

.The invention has been described in connection' with a specific, illustrated embodiment. However, it should be understood that the invention in its broader aspect is not limited to the specific construction herein shown and described since changes in the size, proportion, and mechanical relations, as well as additions, omissions, and substitutions may be made in the construction and assemblyby those skilled in the art without departing from the broad'aspect of this invention.

Having thus disclosed the invention, what is claimed as new and useful and upon which it is desired to secure Letters Patent is:

1. In combination, a low pressure cylinder; a piston operating therein; a high pressure cylinder; a piston operating in said high pressure cylinder, there being cooperating ports in the cylinder wall to control the intake and exhaust of the low pressure cylinder and to'transfer said exhaust to the high pressure cylinder; and a separate valve controlling the exhaust of said high pressure cylinder.

In combination, a low pressure cylinder; a

piston operating therein; a high pressure cylinder; a piston operating in said high pressure cylinder and provided with ,an interior valve chamber, there being cooperating ports in the cylinder walls to control the intake and exhaust of the low pressure cylinder and to transfer said exhaust to the high pressure cylinder; and a separate valve controlling the exhaust of said high pressure cylinder.

3. In combination, a shaft; a low pressure cylinder in operative association therewith and arranged with its axis offset on one side of the. axis of said shaft; a high pressure cylinder in operative association with said shaft and arranged with its axis offset on the other side of the axis of said shaft; a piston operating in said high pressure cylinder and provided with an-interior chamber, there being cooperating ports in the cylinder walls to control the intake and exhaust of the low pressure cylinder and to transfer said exhaust to the high pressure cylinder, and a separate valve controlling the exhaust of said high pressure cylinder.

4. In a compressing machine of the class described in combination, a rotative member, a plurality of cylinders, pistons reciprocating therein, operative connections from the pistons to said rotative member, means on said rotative member to give rectilinear motion to said pistons, adjustable means associated with the first-mentioned means to vary the angular position of the throw for permitting the use of one or more types of refrigerants at their most efiicient working pressure the axes of the cylinders being not in the plane of the axis of the rotative member projected parallel the axes of the cylinders.

In a compressing machine of the class described, in combination, a rotative member, a plurality of cylinders, pistons reciprocating therein, operative connections from said pistons to said rotative member, means disposed upon said rotative member to give rectilinear motion to said pistons, the axes of the cylinders being not in the plane of the axis of the rotative member projected parallel to the axes of the cylinders, and

means for changing the relative angular positions of the rotative means which give rectilinear motion to said pistons for permitting the use of one or more types of refrigerants at their most eflicient working pressure.

6. In'a compressing machine of the class described, in combination, a plurality of cylinders,

reciprocating pistons therein, a closed chamber in the high pressure piston, passages conducting primary pressure refrigerant to ports admitting it to the closed chamber of the high pressure piss ton during part of its stroke, ports arranged to

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