US1736974A - Pump for refrigeration systems - Google Patents

Description

' Nov. 26, 1929. J. (5. KING 1,736,974

PUMP FOR REFRIGERATION SYSTEMS Filed Aug. 3. 1920 3 Sheets-Sheet l 26, 1929. J. G. KING 1,736,974

PUMP FOR REFRIGERATION SYSTEMS Filed Aug. 3. 1920 S Sheets-Sheet 2 Fl 5- 2- I A l i 5.727 E U Nov. 26, 1929. J. G. KING FUN? FOR REF'RIGERA'LI02 1 SYSTEMS Filed Aug. 3. 1920 3 Sheets-Sheet 5 Patented Nov. 26, 1929 UNITED STATES PATENT oFFmE JESSE G. KING, OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO GENERAL MOTORS RESEARCH CORPORATION, OF DAYTON, OHIO, A. CORPORATION OF DELA- WARE PUMP FOR REFRIGERATION STEMS Application filed August 3, 1920. Serial No. 400,894.

This invention relates to devices for trans- .mitting power thru a sealed partition or wall,

posed outside of the casing.

One of the objects of the invention is to provide an improved power transmitting device in which the driving and drivenelements are completely sealed from each her by a More specifically it is an ob; of the invention to provide aii improved power transmitting device in which the elements are sealed from each other by a flexible metalpartition.

Another object of the invention is to so arrange such a partition that it will have great endurance or long life.

Another object is to so arrange the partition that it will be subjected to the minimum stress under 0 erating conditions.

In re rigeration system of the compression type it is common practice to enclose the pump or compressor in a housmg .and to drive the pump by a shaft passing thru a wall of the housing. In such cases it is necessary to use some means such as a packing gland or stufling box around the shaft where it passes thru the wall in order to prevent leakage of the refrigerant. Such acking devices cause considerable friction w1th consequent waste of power and moreover frequently become leaky from wear after a short period of use.

One of the specific objects of the invention is to provide a refrigerating compressor with improved means for sealing the pump from the driving mechanism which eliminates the disadvantages mentioned.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1. is a plan view with parts in section of a refrigeration pump constructed in accordance with the present invention.

Fig. 2 is a horizontal section of another form of pump also constructed in accordance with the invention. Fig. 3 is an end view of the pumps shown in Figs. 1 and 2 with the cover plate removed. F1gs. 4, 5 and 6 show certain details of the ap aratus;

he present application relates to improvements in the pumps forming the subject matter claimed broadly in application Serial No. 397,519, filed July 19, 1920, by the present appllcant.

In the previous application, specific description and claims were to a form of pump in which. the actuation was produced by means'of an oscillating lever. In the present application there is shown a pump consisting chiefly of-elements similar to those shown in the previous application but in which rotary motion is transmitted from the motor or other driving means to rotate an element within the housing containing the pump and from the rotating element motion is transmitted to the pump proper.

In the drawings, in which preferred forms of embodiments of the invention are shown, the housing for the pum is composed of a rigid portion designated by the numeral 10 and a flexible member or portion designated as a whole by the numeral 20. In Fig. 1 this flexible portion 20 is indicated as extending laterally from the rigid portion 10 and in Fig. 2 the flexible portion 20 is 'indicated as a reentrant portion connected with the outer end'of and extending into a hollow cylindrical protuberance extending laterally from one side of the rigid portion 10 of-the pump housing. In both cases, however, the rigid portion together with the flexible portion provides a housing within which the various elements of the pump are contained and which, as will hereinafter appear, is a hermetically sealed from the external atmosphere; the interior of the flexible member bein in communication with the interior of the r1 'd portion of the housing in the form of my 1nvention shown in Figure 1, while in the form shown in Figure 2 the interior of the rigid portion is in direct communicaton with a space surrounding the exterior of said flexible member.

and two pistons adapted to operate in said cylinders, the pistons being carried upon a piston rod 14. This rod 14 is as shown in Fig. 3, preferably constructed in two portions, each having one end shaped to form one half of the yoke 15, and bolted or otherwise secured together so as to form in effect a single rod with the yoke 15 in the middle portion. The piston rod 14 is provided at its central portion with the yoke 15 which coacts with the crank 16 upon the rotatable element 17 or 17 within the housing to produce the reciprocation of the rod and pistons. I prefer to rotate the element 17 by means of a driven member having power transmitting connection with the outside of the casing and partaking simultaneously of two kinds of motion. These two kinds may for example be simple planar oscillation simultaneously in opposite directions as shown in my application No. 397,519, filed July 20, 1920, or as shown in Fig. 2 they may be rotation and nutation.

In the construction shown in Fig. 1 this rotatable element 17 is the continuation of a shaft 18 which is enclosed by the flexible portion 20, of the housing. Inthe form shown in Fig. 2 rotatable element 17 is a separate element adapted to be rotated within the hollow protuberance aforesaid of the rigid portion 10 of the housing and provided with bear ings 19 therein.

As shown in Figs. 1, 2 and 6, the shaft 18 is provided with a portion 18 which rotates in a bearing 18 in the housing, and is provided with a portion 18 set at an angle to the rotating portion 18". It will be apparent that as the portion 18 rotates, the portion 18 nutates. The shaft is surrounded by a non-rotating sealing member generally denoted by 20 which includes a flexible tubular portion 21 and a rigid tubular portion 22. The flexible portion is preferably a corrugated metal bellows, one end of which is hermetically sealed to the casing and the other end of which is hermetically sealed to the rigid ortion 22. The other end of the rigid tubuar portion 22 is sealed to a cap 23' which encloses the end of the shaft 18 forming a bearing for the latter, and is provided with an outer bearing 30. It will thus be apparent that the pump and its driving shaft 18 are entirely enclosed within a sealed housing.

The point l8 at which the portions 18 and 18 of the shaft 18 are joined, and consequently the point at which the change in the motion of the shaft takes place, is referably situated on the normal axis of the bellows midway between the normal positions of the end planes of the bellows, the word normal referring to the position ofthe bellows when free and at rest.

This tubular portion 22 of the flexible,- member 20 of the housing in turn extends into a bearing 30 within a rotating driving member 31 which is attached to a second shaft 32 carrying pulley 33 to which driving power may be applied by means of a belt from a suitable source of power not shown. It is of course obvious that the shaft 32 may be otherwise driven, as by attachin it directly to an electric motor or other orm of power producer. Or this shaft 32 may be eliminated and a motor attached directly to driving member 31.

It is also obvious that the bearings throughout the device may be provided with antifriction devices such as ball or roller bearings so as to increase the efliciency of the apparatus.

In the form of structure shown in Fig. 2, instead of having the driving shaft for the pump entirely enclosed in the same housing with the pump, it is entirely outside of the housing and is surrounded by the flexible portion of said housing. I

In this form of pump, shaft 18 extends into the housing but is completely enclosed by the flexible reent-rant portion 20 of the housin composed of the same elements as are in 'cated in Fi 1, and which form is an effective seal for t e housing as a whole.

In this form of pump also the nutating portion of the shaft 18 extends into the cap portion 40 at the inner end of the tubular portion 22 of the flexible housing, which cap portion in turn extends into a suitable hearing 41 in the rotatable element 17'.

In thisform of pump aswell as in the other forms ball or roller bearings or other antifriction devices may be used at whatever places ma seem desirable.

In the orm of pump shown in Fig. 2 the drivin power is applied to the rotating portion 0 the shaft which extends outside of the flexible portion 20 of the housing. I

In Fig. 2 there has been indicated a form of piston which has been found to be satisfactory and give good results but which in its specific form forms no part of the present application.

This form of piston consists of a body por-' housing. The piston rod is also provided with a valve surface 54 at its end adapted to coact with the valve seat 51 in the end of the piston.

The piston 13 is so mounted u on piston rod 14 as to permit a small longitu inal movement thereon. This is accomplished by means of the slots 55 in the piston rod coactin with the key members 56 in the pistons, whic slots are slightly wider than the key members.

To the outer ends of the cylinders 12 are attached the valve chambers 60 containing valves 61 providing for the outlet of the compressed fluid.

The flexible element 21 is illustrated mor clearly in Figs. 4, 5 and 6 wherein it is shown in its ordinary position unattached to the other elements of the housing (Fig. 4) and wherein it is shown in the position assumed -when shaft 18 is inserted in the flexible part of the housing.

Fig. 5 illustrates the natural flexing of the bellows from which the location of point 18 of the driving shaft is determined. In order to increase the life of the bellows under repeated flexing, and to decrease the resistance offered by the bellows to such flexing and thus decrease the amount of power required for a given amount of flexure.

to drive the apparatus, it is desirable to eliminate side stresses on the bellows, and to subject the bellows to the minimum stress for a given displacement or amount of flexing. That is, when the bellows is flexed, all forces transmitted from one corrugation to the next should act in lines which are as nearly. as possible perpendicular to the planes of the corrugations and should not have any component 'in a direction parallel to such planes. And

moreover such forces between any pair of corrugations should be a minimum for a given flexure of the bellows. If such a bellows is supported with one end fixed and with its axis in a vertical line (so as to eliminate distortion produced by gravity) and the other end of the bellows is free, the bellows will oscillate or vibrate freel when the free end has been subjected to a ending force applied at a single point and the force.

has been suddenly removed. During this free vibration the bellows flexes in its natural manner and it will be evident that in such flexing the bending stresses set up in the bellows at any given point will be a minimum In flexing naturally the bellows takes a form illustrated in Fig. in which the normal axis ab always assumes the form of a simple .curve ag--b which I believe to be a circular are normal to the end planes of the bellows and I believe that the free end c-d of the bellows always remains tangent to a sphere whose center is the point (2 located on the line a-b midway between the normal positions of the V end planes.

Accordingly I construct'and arrange the bellows and the drivin member 31 and the driven member 18 (re 'errin to Fig. 1) or the driving member 18 and t e driven member 17 (referrin to Fig. 2) so that during movement of the riving and driven members the bellows is constrained to flex in its natriral manner, that is to say the plane of the free end of the bellows is maintained tangent to a sphere whose center is the point c. This 1s accom lished .by locating the point of change 0 motion of the member 18 at the point e. This may be effected by locating the bend 18 in the shaft 18 at this point, or as shown in my application 397,519, referred to above, it may be eflected by having the pivot of the oscillating member pass thru this point. I

.Thus in Fig. 5 the lines a-e and 6-1) represent the axes perpendicular to the end planes of the bellows and these lines always intersect at a point on the normal axis of the bellows midway between the normal positions of the end planes. The linesa-e and e-b' also represent the axes of the rotating and nutating portions of the shaft 18. Thus during movement of the driving and driven members the bellows is flexed so as .to oscillate between two positions on either side of its normal axis. In the case illustrated in Serial No. 397,519 this oscillation is simple planar oscillation, while in the embodiment of the invention shown in Figs. 1 and 2 a portion of the bellows nutates, the point 6 being referred to as the center of oscillation (or more specifically in cases where the bellows nutates, as the center of nutation).

Fig. 6 shows in elevation the flexible rtion 20 of the housing attached to cover ate of the protuberance aforesaid as this portion of the apparatus appears when removed from the remainder of the assembly shown in Fig. 2. The flexible portion of the housing, as shown in Fig. 6, is substantially the same in bot-h forms of pump illustrated.

It is thought that the operation of the present apparatus will be entirely obvious from the description and drawings and no detailed discussion will be given other than to indicate the path of fluid through the compressor.

Taking for example the structure shown in Fig. 2 the fluid to be compressed will be drawn in at the inlet when it will pass through the passage-way 53 in the piston rod into chamber 52, through valve 51 'into the compression chamber of the cylinder, this operation taking place upon the suction stroke of the piston. Upon being compressed the gas will pass out through the valve chamber 60 and outlet 81.

The flexible metallic element 21 as illustrated in Figs. 1, 2, 4, 5 and 6 may be'of any suitable form but a form that has been found results is what is known in the trade as a sylphon. These sylphons are corrugated metallic tubes permitting considerable and frequent compression along their longitudinal axis and also permitting considerable and frequent angular movement between their ends. These articles do not form a part of the present application as they are already the subject of, numerous patents and quite well known in the trade. It should be m added that the form of sylphon that has been found satisfactory for the present purpose is the laminated or multiply form, this giving the greatest flexibility with the greatest strength.

1" It will also be noted that while there has been described a two cylinder compressor, a greater number of cylmders, (for example, four) might be found advantageous in special cases and such modification is con- 20 tom lated.

- hile the form of mechanism herein shown and described constitutes a preferred embodiment of one form of the present invention, it will be understood that other 5 forms might be adopted and various changes and alterations made in the shape, size, and

ting means including means for nutating a part of the bellows so that the stresses set up in the bellows by the nutation are a minimum. 5. A power transmittin device comprising in combination a wal and means for transmitting power through the wall including a power transmitting member partaking simultaneously of two movements, and a metal bellows sealed to the wall and connected to said member, and the oint of change of motion in said member ing located substantially midway between the norinal positions of the and planes of the belows.

In testimony whereof I hereto affix my signature.

' JESSE G. KING.

proportion of the elementstherein without departing from the spirit and scope of the invention.

: What is claimed as new is:

1. A power transmitting device comprising in combination a wall; and means for transmitting power through the wall including a power transmitting member having a nutat- 88 mg portion, and a metal bellows sealed to the wall and connected to said nutating portion, the center of nutation of said nutating portion being substantially midway between the normal positions of the end planes of the bellows.

2. A power transmitting device comprising .in combination a wall; and means for transmitting power through the wall including a power transmitting member and a metal bellows sealed to the wall and connected to said member, said power transmitting means includin means for nutating a part of the bellows a out a center substantially midway between the normal positions of the end planes of the bellows.

3. A power transmitting device comprising in combination a wall; and means for transmitting power through the wall including a power transmitting member, and a metal bellows sealed to the wall and connected to said member, the power transmitting means including means for nutating a part of the bellowsto cause the bellows to partake of its natural flexing movement.

4. A power transmitting device comprising in combination a wall; and means for transmitting power through the wall including a power transmitting member, and a metal bellows sealed to the wall and connected to said member, the power transmit- III

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