US1436443A - Pump - Google Patents

Description

B. B. HOLMES.

PUMP. APPLICATION FILED SEPT- 3.1919.

1,436,443. at d ov. 21, 1922.

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INVENTOR a? v BY W 'ZECAKATTORNEY Patented New. 21, 1 922. v

BRADFdRD B. HOLMES, 01 THE UNITED STATES ARMY.

PUMP.

Application filed. September 3, 1919. Serial No. 321,352.

. To all whom it may concern:

Be it known that I, BRADFORD HOLMES, a citizen of the United States, major, Coast Artillery, United StatesArmy, stationed at Washington, District of Columbia, have in vented an Improvement iir Pumps, of which the following is a specification.

My present invention relates more particularly to compression pumps such as are used in rconnection with refrigeratingmachines, and more particularly to pumps designed to form a part of small refrigerating machines of. the compression-extension type adapted to householduse.

Generallystated the pump element of such machines is designed to compress a'gaseous fluid as, for instance, sulphur-dioxide and to expel it under compressionvinto a condenser where it is liquefied.

. corrugations The well rugations which can rendered practically For such purposes my present invention contemplates a motor-driven pump which}; make leakless by employment of a fl'exible metallic bellows between the pump piston and cylinder. Preferably the dead space between the metallic bellows and the cylinder wall is filled with. oil or glycerine, both for the purpose'of decreasing possibility of leakage of the gaseous fluid to be compressed, and also to decrease the cleardesired I may employing a surplus of the oil. The flexible metallic bellows may consist of ametal tube rolled or otherwise formed with circular or helical convolutions or cor The tube is thin enoughrandithe deep enough and closely enough spaced to give the desired lengthwise flexibility required to permit full stroke of the pump piston without fatiguing the metaL known Fulton sylphon tubes may be employed for this purpose where circular corrugations are desired, but I also contemplate utilizing tubes with helicaLcorbemade by methods other than those employed by Fulton.

I have discovered that when corrugated tubes, either the circular or helical type, are

rugations.

; made of suflicient lengthwith respect to the piston stroke, all fatigue of the metal may be avoided and this element of'the' pump immune to deterioration or wear; that no matter what length of tube is required for this purpose, the dead space thus introduced in the compression other is the 'glycerine or oil.

cavity can be eliminated by filling said space though the tubes are of considerable length, and very flexible by reason of thinness of walls, depth, corrugation and length ofthe tube, they will automatically tend to maintain a true. cylinder outline with corresponding parts always equidistant from a straight line axis, when arranged so that the high compression takes effect on the exterior of the tube instead of on the interior, provided the two ends of the tube are kept parallel with each other at right angles to and concentric with the axis. This of course requires that the piston element to which the movable end of the tube is secured, .be rigidly guided for movement in a line parallel with the axis of said tube.

In my device there are two fluids circulating through the pump circuit. One is the gaseous medium to be compressed, and the The oil is used in the pump to fill up the dead space, seal in the" valves, to lubricate them, and to'cut down clearance. This is an important fea ture as it causes my pump to operate at maximum efliciency and with minimum electrical consumption. r1 i The degree of compression of the gaseous fluid in my pump may be regulated within wide limits by regulating the supply of-oil to decrease or increase the clearance. As the clearance can be decreased to zero, the maximum compression attainable will be limited only by the power applied to the driving mechanism by the motor, any desired lesser degree of compression being attainable by merely varying the back pressure on the outlet. Other features of the device are automatic lubrication of the pump driving mechanism and motor, silence and neat appearance. Furthermore, the apparatus is not complicated, requires no attention, is extremely durable, and not too expensive for general use.

The above and other features of my invention may be more fully understood from the following description in connection with the accompanying drawings, in which Figure 1 is a vertical central section in the plane of the axes of pump and drive shaft;

Figure 2 is a plan section of the top casting OIL the line 2-2, Figure 1;

flexible coupling. 14, which may be any suitabletype. The worm 13 rotates in the bearings 15 and 16 and against the thrust discs 17. he worm engages with and turns the worm wheel 18, whose bearing 19 rotates in a bushing 20 held in its bed in the base cast- I in 11 by the yoke 21.

he worni wheel 18 gives reciprocating motion to the pump piston 22 by means of the connecting rod 23. The worm wheel revolves in oil so that oil is carried 'to the rapidly rotating worm which throws oil I and 27 carry piston.

spray about, lubricating the worm and worm wheel bearings, .the connecting rod bearings and the cylindrical guide 24 for the pump pipe 25'With two upright pipes 26 oil to two wicks (not shown) which lubricate the motor bearings.

. An oil .filler pipe and fittings 28 closed with a wing top plug 29 supplies an easy A small method of testing the lubricating oil; level,

and adding additional 'oil when necessary. The entire external lubrication ofthe machine is thus supplied byjpouring .oil' in the inlet 28.

Secured to the base casting 11,;isan inter- "mediate casting. 30 This casting contains the supports for worm bearings: 15 and 16,

I cylindrical guide 24. ,for'the' -pump piston,

axis of the tube and are secured .the sliding joint between the cooling water inlet" '31, cooling water outlet 32, condenser pipe ,bushing 34, and threaded sleeves 33, 33. for the pump cylinder 35 and condenser cylinder 36.

The ends of the tube constitutin the flexible metallic bellows 37, are cut 0 squarely at right angles to 7 the main longitudinal by soldermg or other means, one end to the piston element 22 and the other end to closure for r piston and cylinder elements of the pump. v As beforel internally extending hermetic stated this bellows may be constructed from a metal tube-rolled or otherwise formed with circular or helical convolutions deep enough and close enough spaced to give the desired lengthwise flexibility. I

The piston 22, pump guide 24 and bellows tube 37 are parallel so that the movable end of the tube 37 is parallel with the fixed'end all positions thereof. Hence reciprocat on of the piston requires only uniform exlows tube, rather the casting 30, so that said bellows tube constitutes'anpansion and contraction ofthe corrugations of the tube in a direction parallel with the tube axis, and the tube is long enough so that the amount of bending of the metal is, at all points, well within the limits of fatigue of the metal. The only other stresses taking effect on the bellows tube are external pres-., sures applied with perfect uniformity through the oil or other medium filling the space between the bellows tube 37 and cylinder 35. Such pressures, though uniformly applied, are not uniformly resisted by the walls of the tube, since the'latter can never be made perfectly uniform .and symmetrical, in construction, particularly as to thick-' ness and resilience 'of the material. This might be expected to result in lateral bulging and crooking of the tube, and it does do so when the pressure is internally applied.

I have discovered, however, that when the pressures are externally applied any inequalities of the resistances to the pressures areautomatically compensated for so thatthe net result is not to crook the tube but, on the contrary, the external pressure will tend to straighten out crooks in a previously crooked tube. Hence, it will be seen that an important feature of my invention consists in causing the hi h pumping pressures to take effect externa ly of the corrugated belthan internally thereof. Approximately uniform atmospheric pressure is maintained within the bellows tube by openings 24 communicating with atmos phere through the base of the engine. These openings also permit access of lubricant to the interior of the bellows tube As a reto crook into engagement either with the piston guide which it surrounds, or with the piimp cylinder by which it is surrounded.

oreover, if the stralghtening e'flect of the external pressure proves insuflicient to prevent all contact, such contact as occurs will be slight'and will be unproductive of Wear jsult thereis no tendency of'the bellows tube because of the above described arrangement i for interior as well as the tube. v

The top of pump cylinder 35 is threaded to take the top casting 38. The top end of condenser cylinder 36 is beveled, and as exterior lubrication of ,casting 38-.is screwed down on cylinder-35, thebeveled edge fits tightly against it making a water tight joint. The packing rings 39 and 40 assist in ensuring that the joint is water tight. 4

The pump cylinder 35, intermediate cast mg 30, and top casting 38, are carefully threaded and the threads sealed with suitable thread filling compound and gaskets so that the joints between the cylinder and castings are gas tight.

Top casting 38 is supplied with the suctron valve 41, suction valve housing 42, suction valve closing spring 41, suction valve retainer and spring 45, outlet valve seat 46,

oil settling chamber 47, outlet passage 48, 'ball check valve inlet 49, inlet sealing plug 50, and cooling water outlet 32.

A suction pipe 56 is secured by bushing 43 to the top of the suction valve chamber, and a compression conduit which may be a condenser pipe 57, is soldered into a hole drilled to meet the outlet passage 48. Suction pipe 56 leads from the source of fluid to be pumped or condensed, as for instance the evaporator of a refrigerating machine. Pipe 57 is coiled in the chamber between 35 and 36 and may constitute the condensing element of the refrigerator. Pipe 57 leaves said chamber through the bushing 34 and its outlet is controlled by valve 74.

Cooling Water is admitted from the water main to the condenser by pipe 58, and the warmed discharged condenser water drips away through pipe 59.

Beciprocation of the pump piston '22 causes the oil level in the pump chamber to rise and fall, sucking in gas through pipe 56 and expelling it under pressure to the pipe 57 where it may be condensed by its .pressure and by being cooled.

As gas is forced out of the pump chamber through valve 44, it will tend to carry a little oil with it. Most of the oil settles out in the chamber 47, and a slight leak in the valve 44, purposely provided for by leaving the hole for the wire valve retainer 45 a little large, allows a few drops of oil to drip back on the suction stroke into the pump chamber, thus ensuring always a slight excess of oil and, consequently, no clearance.

From the foregoing description it is evident that this invention can be carried out in other forms by the use of other materials and other fluids than as above described. Therefore, I do not limit myself to the struc ture or materials described in the preferred form, but include all other forms and materials by which this invention may be realized which are within the spirit of the invention and Within the scope of my claims.

What I claim is 1. In a pressure pump apparatus, the

. combination of a pump chamber comprising a cylinder, a piston, and a metallic bellows secured at one end to said cylinder and at the other end to said piston; inlet and outlet valves, and a liquid filler completely filling said pump chamber when tl-e pump piston is at its nearest point to the cylinder .head.

2. In a pressure pump apparatus, the combination of two relatively movable pump elements; flexible metallic bellows connecting the same and forming therewith a gas pump chamber; suitableinlet and exhaust valves; and a liquid contained in said pump chamber to reduce the elfective clearance.

pump; and a top thereby,

3. In a pressure pump apparatus, the

combination of a pump comprising acylinder element, a piston element and a metallic bellows secured at one end to said cylinder, and at the other. end to -said piston; a liquid filler completely filling said pump chamber when the piston is at its nearest approach to the cylinder head; an inlet valve, and an outlet valve so constructed as to allow a slight leakage of liquid past saidvalve.

4. In a pressure pump apparatus, the

combination of two relatively movable pump elements; flexible metallic bellows connecting the same and forming therewith a gaspump chamber; suitable inlet and exhaust valves for said chamber; a liquid contained in said pump chamber to minimize the-clearance ;a reservoir beyond the discharge valve adapted to retain liquid passing the discharge valve; and a minute port leading from said reservoirto said pump cylinder to lead liquid slowly from said reservoir back tosaid pump chamber.

5. In a pressure pump apparatus, in combination, a pump comprising two relatively movable pump elements and a metal-' lic bellows secured to one of said pump elements at one end and to the other of said elements at the other end; the arrangement of parts being such that the interior pump pressures take effect on the exterior of the bellows.

6. In a compressor, the combination of a gas pump having a discharge leading from its top; a liquid retaining separating-reservoir fed by said discharge; a bleed port leading from said reservoir back to said discharge from said res-' ervoir. v

7. .A gas compressor comprising a cham-- ber element and a piston element and means for relatively moving one with respect to the other, and a flexible metallic bellows secured to and extending between said elements parallel with the direction of their relative movement and having the pressure ,of the compressed gas applied on the exterior of the bellows.

8. A gas compressor comprising a-cylin'- I a 115 der, a piston and means for guiding it within said cylinder, in combination with a corrugated, longitudinally flexible tube extending within said cylinder and secured at one end to said piston and at the other end over the open end of the cylinder, said tube being coaxial with said cylinder and piston elements and arranged so that in operation the pressure of the compressed gas takes effect on the exterior of said tube.

9. A gas compressor "comprisinga pump cylinder and, concentric therewith, a piston guide of substantially smaller diameter and less length extending inwardly from one end of said pump cylinder; a piston guided an approximately cylindrical,

square-ended, thin;walled, deeply-corrugated, longitudinally-flexible, spring metal tube located, in the space between the cylinder and pistonguide secured at one end to the -piston and at the othenend to an 'anchorage' surrounding the piston guide openingin such relation as to be normally without any substantial pressure of sliding contact with adjacent exterior or interior parts of the mechanism and to have gas pressures generated by the compression strokes of the pump taking effect on the exterior of said tube.

10. A gas compressor comprising a pump cylinder and, concentric therewith, a piston guide of substantially smaller diameter and less length extending inwardly from one end of said pump cylinder; a piston guided thereby, P an approximately cylindrical, square-ended, thin-walled, deeply-corrugated, longitudinall y-flexible, spring metal tube located in the space between the cylinder and piston guide secured at one end to the piston and at the other end to anchorage surrounding the piston guide opening in such relation as to be normally'without any substantial pressure of sliding contact with adjacent exterior or interior parts of.

the mechanism and to have gas pressures generated by the compression strokes of the pump taking effect on the exterior of said tube, and means for maintaining the interior of said tube at a much lower pressure.

11. A gas compressor comprising a pump cylinder and, concentric therewith, a piston guide of substantially smaller diameter and less length extending inwardly from one end of said pump cylinder; a'i piston guided thereby, an approximately cylindrical, square-ended, thin-walled deeply-corruinder and gated, longitudinally-flexible; spring metal tube located in the space between the cylpiston guide secured at one end to the piston and at the other end to anchorage surrounding the piston guide opening in such relation as to be normally without any substantial pressure of sliding contact with adjacent exterior or interior parts of the mechanism and to have gas pressures generated by the compression strokes of the pump taking effect on the exterior of said tube, and means for maintaining the interior of said tube at a much lower pressure and for lubricating said interior; 65

12. A gas compressor comprising a pump cylinder and a piston concentric therewith, means for reciprocating said piston through an opening in one end of. said cylinder to varythe volume of compression space within said cylinder, a suitably valved inlet and outlet for said compression space, an approximately straight, square-headed, thin walled, 'circumferentially-corrugated, longitudinally-fie'xible, spring-metal tube located in the space between the cylinder and the piston reciprocating means, secured at one end to the piston and at the other end to an anchorage surrounding the opening through which the piston reciprocating means extends, and'arranged to have the gas pressures generated by the compression strokes of the pump take efiect on the exterior of said tube, the normal length of the tube and the distance between the points at Which its ends are secured being very great as. compared with the stroke of the piston. 1

13. A gas compressor comprising a pump cylinder and a piston concentric therewith, means for reciprocating said piston through an opening in one end of said cylinder to vary the volume of compression space with- I in said cylinder, a suitably valved inlet and outlet for said compression space, an approximately! straight, square-ended, thin walled, circumferentially-corrugated, longitudinally-flexible, spring-metal tube located in the space between the cylinder and the piston reciprocating means, secured at one end to the piston and at the other end to an anchorage surrounding the opening through which the piston reciprocating means extends, and arranged to have the gas pressures generated by the compression "strokes of the pump take eil'ect on the exterior of said tube, the normal length of the tube and the distance between the points at vwhich its ends are secured being very great as compared with the stroke of the piston, in combination with means for supplying the power to reciprocate the piston, including a power driven worm. and a worm gear provided with a crank pin adjacent the said opening in the end of said cylinder and the means for translating the crank pin motion into reciprocating motion of the piston consisting of a link extending from said pin through said opening and connected to the piston at a point near the head thereof,

14. A gascompressor comprising a pump cylinder and a piston concentric therewith, means for reciprocating said piston through an opening in one end of said cylinder to the piston reciprocating means, secured at one end to the piston and at the other end to an anchorage surrounding the opening through which the piston reciprocating means extends, and arranged to have the gas pressures generated by the compression strokes of the pump take efi'ect on the exterior of said tube, the normal length of the tube and the distance between the points piston, in combination with-means for supplying the power to reciprocate the plston, including a power driven crank pin adjacent the said opening in the end of said cylinder and the means for translating the crank pin motion intoreciprocating motion of the piston consisting of. a link extending from sad-pin through said opening and connected to the piston at a point near the head thereof, and means for maintaining a body of oil in bathing relation to said crank pin for splash feed lubrication of the parts'including the interiorof said tube.

'15. In a pressure pump apparatus, in

, combination, a pump comprising relatively movable pump elements and a metallic bellows secured to one of said pump elements at one end and to the' other of said elements at the other end; the arrangement of parts being such that fluid pressures created by the pump apply pressure on the exterior of the bellows. I

16. A pressure pump apparatus including a reciprocating piston for applying pressure within the apparatus, means for operating it through an opening to the exterior,

and means for sealing said piston against escape of fluid, consisting of an imperforate, thin-walled, metal bellows tube, deeply corrugated circumferentially, secured airtight at one end to the rear of said piston with its intermediate 'portion surrounding the piston reciprocating element, and its other end secured air tight about said opening; and means affording fluid pressures which are much greater on the exterior of the tube than on the interior thereof, for the purpose of keeping the. tube straight.

17.. A pressure pump apparatus including a reciprocating piston for applying pressure within the apparatus, means for operating it through an opening tothe exterior, and means for sealing said piston against escape of fluid, consisting of an imperforate, thinwalled, metal bellows tube, deeply corrugated circumferentially, secured air-tight at one end to the rear of-said piston with,

its intermediate portion surrounding the piston reciprocating element, and 1ts other end secured air tight about said opening;-

and means applying fluid pressures of the pump on the exterior of the tube and approximately atmospheric pressures on the said passage consisting of an imperforate,

thimwalled, metal bellows deeply corrugated circumferentially, having one end sealed air tight around said passage and. the other end extending into-the cavity within said pressure chamber, a reciprocating piston to'the rear of which the inner end of said tube is secured air tight so that the piston forms an, air tight closure for said inner end, in combination with exterior driving means including a link extending through said passageand into said bellows and connected to impart predetermined limited movement to said movable piston; and cooperating elements including the piston head on the inner side for utilizing within the chamber the relative'movements imparted thereto from the outside thereof.

19.A chamber adapted to contain fluids under pressure sealed against escape to the outer air, an opening affording a passage from the exterior into the chamber cavity; a closure for said passage consisting of an imperforate, thin walled, metal bellows deeply corrugated circumferentially, having one end sealed air tight around said passage and the other end extending into the cavity within said pressure chamber, and a relatively movable member to the rear side of which the inner end ofsaid tube is secured air tight and for which it forms an air tight closure, in combination with ex- "terior driving means extending through contact with the outer surface of the bellows tube, operating to cushion and damp vibrations thereof.

In testimony whereof I have signed my name to this 1pecification.

ADFORD B. HOLMES,

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