US2955750A - Multi-cylinder reciprocating compressor - Google Patents

Description

Oct. 11, 1960 T. w. PHELPS 2,955,750

MULTL-CYLINDER RECIPROCATING COMPRESSOR Filed May 9, 1958 2 Sheets-Sheet 1 4 FIG.

1e 50 so 34 INVENTOR.

THOMAS w. PHELPS FIG. 2

na am ATTORNEYS Oct. 11, 1960 T. w. PHELPS 2,955,750

MULTI-CYLINDER RECIPROCATING COMPRESSOR Filed May 9, 1958 2 Sheets-Sheet 2 F|G 3 INVENTOR.

THOMAS w. PHELPS xna W ATTORNEYS Patented Oct. 11, 1960 MULTI-CYLINDER RECIPROCATING COMPRESSOR Thomas W. Phelps, La Crescent, Minn., assignor to The Trane Company, La Crosse, Wis., a corporation of WIS- consin Filed May 9, 1958, Ser. No. 734,135

Claims. (Cl. 230-187) This invention relates in general to a multi-cylinder compressor with an odd number of cylinders and relates more particularly to a refrigeration compressor with an odd number of operating cylinders in the next larger even-numbered cylinder compressor housing.

One object of the invention is to provide a refrigeration compressor with an odd number of cylinders which has a capacity intermediate that of the even-numbered cylinder compressors on either side of the desired intermediate capacity. 7 p

Another object of the invention is to provide a refrigeration compressor which is simple and durable in construction and which also has a high operating efficiency.

A third object of the invention is to provide a refriger ation compressor which is easily and cheaply produced without stocking excess components other than that employed in an existing line of refrigerant compressors which have an even number of cylinders.

Another object of the invention is to provide a refrigerant compressor with an odd number of cylinders which employs the component parts of the next larger evennumbered refrigerant compressor in numerical order of cylinders.

A fifth object of the invention is to provide three, five, and seven cylinder refrigeration compressors employing the component parts of the eight, six, and four cylinder compressors, respectively.

'A further object of the invention is to provide a refrigeration compressor which is produced by de-activating one cylinder of the next larger compressor in order to produce a compressor of lesser capacity. I V

The seventh object of the invention is to provide a compressor to handle intermediate capacities which will decrease wear and tear on the component parts of the compressor by elimination of excessive starting and stopping of the compressor. Other objects and advantages of the invention will be clearly apparent asthe specification proceeds to describe the invention with reference to the accompanying drawings in which:

Fig. 1 is a roll-out view of a typical six cylinder compressor to which my invention is adapted. v I

Fig. 2 is a partial section view of one bank of cylinders of a refrigeration compressor showing one form of my invention. I

Fig. 3 is a partial section view similar to that of Fig. 2 showing another form of my invention.

Fig. 4 is a top plan view of the cylinder closure plate shown in Fig. 3.

Fig. 5 is a sectional view on line 55 of Fig. 3 showing a typical bob weight employed in my invention.

While my invention is shown and described specifically in reference to a six cylinder refrigeration compressor, it is readily seen that my invention is also applicable to a refrigeration compressor having eight or four cylinders.

Previous to this time, if refrigeration load requirements fell between the ratings of two even-numbered cylinder compressors (e.g.between a' six cylinder compressor and a four cylinder compressor), the larger capacity compressor was selected for the installation. This he 'sulted in higher operating expenses for the consumer as well as additional wear and tear on the compressor due to excess starting and stopping of the compressor. My invention provides a compressor which will meet the .above intermediate capacities and which does not necessita-te the stocking of an entire new line of castings and running -gear other than that normally used with the next larger capacity refrigeration compressor of an even-numbered cylindered construction.

In the drawings, Fig. 1 shows a typical arrangement of cylinder banks 10, 12, and 14 in a six cylinder compressor, each cylinder bank having two cylinders 16 and 18 therein. As is known in the art, the centerline (not shown) of cylinder bank 12 is located at the top of the cylinder housing while the centerline (not shown) of cylinder banks 10 and 14 are displaced at an angle of 60 counterclockwise and clockwise around the periphery of the cylinder housing from the centerline of cylinder bank 12.

Fig. 2 illustrates a partial sectional View of thebank of cylinders to which my invention is applied. Preferably either cylinder bank 10 or 14 is selected for the reasons herein described. Basically my invention involves the deactivation of one cylinder of the compressor to have a five cylinder compressor which has a capacitiy less than that ofa six cylinder compressor but greater than that of a four cylinder compressor.

The compressor comprises, in general, a compressor housing with a crankshaft 22 having two throws 24 and 26 therein. Each throw 24 and 26 has connecting rods 28 rotatable thereon to drive a piston 30 in cylinder bore 32, defined by cylinder liner 34, to draw refrigerant gas from suction chamber 36 through suction openings 38 into cylinder bore 32. The refrigerant gas is then compressed and discharged into discharge chamber 40 on the upstroke of piston 30 and ejected through discharge manifold 42. The discharge valve cage 44 is held in place by spring 46 which is strong enough to secure the discharge valve cage 44 under normal operating pressures but will be compressed in order to allow the discharge valve cage 44 to move upwardly if a slug of liquid refrigerant should be present in the cylinder bore 32. The spring 46 is held in place by the cylinder head 48. The above recited operation is typical for all the cylinders in the compressor.

For many applications, an eight, six, or four cylinder compressor may be too large and a compressor of intermediate capacity is desired. This is accomplished by de-activating one cylinder of the above even-cylinde'red compressors. The housing bores of the de-activated cylinder will be plugged, the running gear on the crankshaft removed, and the crankshaft balanced to compensate for the eliminated running gear. It has been found that the Weight of the above bob Weight is equal one-half the Weight of the reciprocating elements plus the equivalent weight of the rotating elements. The weight of the reciprocating elements being the weight of piston 30 with components such as wrist pin and piston rings normally used with reciprocating pistons plus the equivalent weight of the upper end of the connecting rod 28 undergoing pure translation. The equivalent weight of the rotating elements being the equivalent weight of the lower end of the connecting rod 28 adjacent the crankshaft 22 undergoing pure rotary motion. The above mentioned elements are the elements which normally would be operably associated with the de-activated cylinder if the cylinder had not be de-activated. p

As shown in Fig. 2, the preferred method of tie-actiat'ing one cylinder of the compressor is to remove the running gear from the crankshaft, cast the housing bores 48 and 50 closed, and fill the vacant area 52 on the 1 and crankshaft 22. While casting the. compressor housing, the sand core filling the housing bores 48'and 50 is pulled allowing these bores to fill up with metal thereby closing ofi One cylinder of the compressor.

Similarly, the area 52 shown in dotted lines in Fig. 2, left on the crankshaft 22 by the removal of the running gear, is cast over as the crankshaft is cast. As stated above, preferably one of the cylinders of either cylinder bank or 14 is de-activated since as a practical matter, it is easier to compensate for the elimination of the running gear of the de-activated cylinder by extending one of the shoulders 54 of the crankshaft during the casting of the crankshaft rather than filling in an intermediate area on the crankshaft 22 which would be left if either of cylinders 16 or 18 of cylinder bank 12 were de-activated.

Obviously, I have provided a five cylinder compressor using the components of a six cylinder compressor which required only a slight modification from that of the six cylinder compressor in order to produce a five cylinder compressor of intermediate capacity.

The above five cylinder compressor is produced during unnecessary stocking of component parts other than that required by the normal eight, six, or four cylinder compressor. Further, I have provided a compressor of intermediate capacity which can be produced at the cost of or lower than the cost of the nextlarger compressor. The modifications made involve changes which can be made with a minimum of'man-hours and at a reduction in cost of material, thereby providing a new line of compressors at minimum expense.

, .Althoughlhave .describedin detail the preferred embodiments of my invention, I contemplate that many changes may be made; without departing from the scope or spirit of my invention, and I desire to be limited only by the claims.

I claim:

l. A compressor comprising; a housing, an even number of cylinders in said housing, cylinder heads covering said cylinders and attached to said housing, a crankshaft in said housing having a multiplicity of throws, means in and sealing closed one of said cylinders to render said cylinder incapable 'of operation, piston means slidably supported in the remaining operable cylinders, balancing means approximately equal in weight to the rotating elements of one cylinder plus one-half the equivthe manufacturing process but obviously such modificav V tion can also be produced by the modification of a completed compressor.

The modification shown in Figs. 3-5 encompasses the alteration of a completed six cylinder compressor to convertsaid compressor into a five cylinder compressor. In. the modification of Figs. 3-5, like elements shown in Fig. 2 and'Figs. 3-5 are denoted by like reference numbers.

The modification shown in Figs. 3-5 encompasses the alteration of a completed'six cylinder compressor to obtain a five cylinder compressor of lesser capacity. The cylinder 1iner34, discharge valve cage 44, and all the running gear are'removed and a cylinder closure plate 56 is inserted in the cylinder to close the compressor housing bores 48 and 50. An O-ring 57.is inserted in a recess 59 to seal the cylinder closure plate so that no refrigerant gas passes from the discharge chamber to the suction chamber past the closure plate. A series of projections 58 are formed on' the top of the closure'plate 56to accommodate spring 46 so that spring 46 may encircle ridges 62 on projections 58 to secure .the closure plug 56 in position. 'The other end of spring 46 is held in place by the cylinder head 48.

The vacant area on the crankshaft 22 left by the removal of the running gear is occupied by a bob weight 7 64 which is equal in weight to the weight of the removed rotating elements plus one-half the equivalent Weight of the reciprocating elements. The weight of the reciprocating'elements being the weight of piston'30 with comalent weight of the reciprocating elements of one cylinder connected to and surrounding one throw of said crankshaft to compensate for the elimination of the running gear of said closed cylinder, and connecting rods connecting the remaining cylinders to said throws;

' 2. A compressor comprising; a housing, an even number of cylinders in said housing, cylinder heads covering said cylinders and attached to said housing, a crankshaft in said housinghaving a first throw and a second throw, means in and sealing closed one of said cylinders to render said cylinder incapable of operation, piston means slidably supported in the remaining operable cylinders, connecting rods connecting a, number of pistons equal to half of said even number of cylinders to said first throw, connecting rods connecting the remaining pistons to said second throw, and balancing means approximately equal in weight to the weight of the rotating elements of one cylinder plus one-half the equivalent weight of the reciprocating elements of one cylinder connected to and surrounding said second throw adjacent said connecting rods to compensate for the elimination of the running gear of said sealed cylinder.

3. The structure of claim 2 wherein said means in and V sealing closed one of said cylinders is a cylinder closure ponents such as wrist pin and piston rings normally used a with reciprocating pistons plus the equivalent weight of the upper endof the connecting rod 28 undergoing pure translation. 7 The equivalent weight of the rotating elements being the equivalent weight of the lower end of the connecting rod 28 adjacent the crankshaft 22 undergoing pure rotary motion. The above mentioned elements are the elements which normally would be operably associated with the de-activated cylinder if the cylin- V der had not been de-activated. Bob weight 64 consists of two semi-circular elements 66 and 68 secured around the crankshaft 22 by means of screws 70. Elements 66 and 68 are recessed as at 72 to accommodate the screw heads of screws 70.

By my above invention, it can readily be seen that I have provided an odd-cylindered compressor which will fill the needs of installations requiring compressors of intermediate capacity and which can be produced without plate, sealing means located between said cylinder closure plate and said cylinder to prevent the bypass of gases from the discharge chamber to the suction chamber around said closure plate, and said balancing means being a bob weight.

4. A compressor comprising; a housing, an even number of cylinders in said housing, cylinder heads covering said cylinders and attached to said housing, a crankshaft in said housing having a first throw'and a second throw, a cylinder closure plate in one of said cylinders, spring means between said cylinder head and said cylinder'closure plate holding saidcylinder closure plate in position, connecting rods connecting the remaining operable cylinders to said second throw, and an annular member surrounding and mounted. on said second throw adjacent said connecting rods approximately equal in weight to the weight of the rotating elements of one cyliner plus one-half the equivalent weight of the reciprocating elements of one cylinder to compensate for the elimination of the running gear of said sealed cylinder.

area under one of said cylinder heads, the rest of said housing area under said one cylinder head being imperforate, an even number, of cylinders in said housing under the other of said cylinder heads, piston means slidably supported in said cylinders, a crankshaft having a multiplicity of throws in said housing, connecting rods connecting said piston means to said throws of said crankshafts, and means surrounding and connected to one of said throws approximately equal in weight to the weight of the rotating elements of one cylinder plus one-half the equivalent weight of the reciprocating elements of one cylinder to balance the assembly of the crankshaft and the running gear of the compressor.

References Cited in the file of this patent UNITED STATES PATENTS Esnault Apr. 29, 1913 Goodrich Oct. 12, 1920 Hoffman Feb. 13, 1934 Davey Feb. 10, 1948 Fischer Oct. 26, 1948 Fischer Nov. 23, 1948 Eaton Mar. 27, 1956

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