US2415060A - Pumping system - Google Patents

Description

Jan. 28, 1947. I J. w. CRAIG 2,415,060 I PUMPING SYSTEM Filed Oct. 31, 1942 Sheets-Sheet 1 mvmok.

JOHN w. CRNG BY 5 A.

AT ORNEV Jan. 28, 1947. J. w. CRAIG PUMPING SYSTEM Filed Oct. 31, 1942 4 Sheets-Sheet 2 JOHN w. cRmG Jan. 28, 1947. J, w, mg; 2,415,060

PUMPING SYSTEM 6 INVENTOR. JOHN W- RA\ BY ATTORNEV Q Patented Jan. 28,

PUMPING SYSTEM John W. Craig, Cincinnati, Ohio, assignor to The Crosley Corporation, Cincinnati, Ohio, at corporation of Ohio Application October 31, 1942, Serial No. 464,066

3 Claims. 1

The invention relates to pumps of the reciprocating, single stroke, diaphragm type and is particularly concerned with pumping systems which will produce a rapid and substantially constant fluid flow at relatively low pressures. While pumps embodying the invention may be useful in pumping liquids, their primary purpose is for pumping compressible fluids such as gases and gas mixtures. The invention has particular application to the generation of a rapid and substantially constant air flow for the purpose of rotating turbines at high speed.

By the use of the pumping system of the present invention it is possible to obtain substantially uniform speeds of the order of 10,000 R. P. M. from a prime mover rotating at speeds of the order of 1700 or 1800 R. P. M.

An object of the invention is to provide a simple and effective pump having long life which will produce a rapid and constant flow of gas or gas mixtures which I shall subsequently refer to as air in order to achieve uniform turbine speeds.

Another object is to provid a device by which the air is sealed within a closed system and maintained in a substantially constant state of dehydration and is therefore unaffected by changes in pressure and humidity of the atmosphere in which the system is used.

A further object. is the provision of means to control the temperature of the air so that the fluctuations in pressure necessarily produced by the action of the pump may be maintained within relatively narrowlimits.

A further object is to provide a pump which has such a small stroke and whose moving parts are of such small size and weight that it can be effectively driven direct from an electric motor or other power source.

A further object is vto provide a pump of the reciprocating type which requires no wrist pin or bearing joining, the connectin rod to the piston and which carries the head of the piston on a flexible diaphragm. l

A further object is to provide a flexible diaphragm of long life which serves the three-fold purpose of providing a piston or pressure surface for compressing air, acting as. a bearing to hold the top of the piston follower and sealing the compression chamber from those parts of the device which produce and apply power to the piston.

A further object is to provide a diaphragm pump of the nature described having a. long life and being capable of easy servicing in the field by inexperienced personnel.

A further object is to provide interior, integrally formed chambers serving as surge tanks and facilitating the smooth flow of air without pulsations.

A still further object is to provide a pressure regulator integrally built into the hermetically sealed system in order to maintain accurate control of the pressure within the system.

A still further object is to provide an air-tight, water-tight and explosion-proof crank case constructed so that itwill house accessory parts and which can be operated under water. I

The novel features that I consider characteristic of my invention are set forth in the appended claims; the invention itself, however, both as to its organization and its method of operation together with additional objects and advantages thereof will best be understood from the foll0wing description of a specific embodiment when read in conjunction with the accompanying drawings, in which Figure 1 is a side elevation of a device embodying the advantages of the invention,

Figure 2 is a front elevation thereof with parts broken away to show parts in section, taken along line 2-2 of Figure 1 showin the pump piston at the lower end of its stroke,

Figure 3 is a plan view of the illustrative device. with parts broken away to show parts in section,

Figure 4 is a partial section taken along lines 4-4 of Figure 2, showing the piston atthe upper end of its stroke,

Figure 5 is a partial section similar to Figure 4, showing the piston at a position removed from those shown in Figures 2 and 4,

Figure 6 is a bottom view of an exhaust valve which maybe used to permit the compressed air to move out of the compression chamber of the cylinder, and I Figure 7 is a section taken on line 1-1 of Figure 6.

Briefly described, the illustrated device comprises a housing l0 suitably mounted as on a bracket II. To the top portion of the housing which may be of cast steel and preferably integrally formed therewith, is a cylinder block I011 having passagesformed in its outer portions and containing cylinder l2 and compression chamber rubber sold under the trade name Neoprene, is particularly suitable for the purposes of the invention. The follower I4 is secured to a connectnecting rod and piston assembly.

The cylinder block and head are provided with valves and passageways which will be referred to in the following portion of this brief description of the operation of the system.

Oscillation of the piston causes air to flow from compression chamber I2a through an opening 22 in head I3, said opening containing exhaust valve 23, passageway 24, opening 25' (see Fig. 3) and down into a chamber 26 located within the cylinder block Illa. This chamber can be seen in the brokenaway part of Fig. 3 and is behind the partition 21 shown in Figures 2 and 3. Chamber 26 communicates with casing 30 which contains a dehydrating agent such as plaster of Paris through chamber 28 and conduit 29 and leaves the casing through conduit 3|, which is connected to the turbine or other device to be driven by' the flow of air through the system.

Upon its return to the pump the air flows through conduits 32 and 33 into chamber 34, which communicates with chamber 35 in cylinder block Illa, up through opening 36 into chamber 31 in head [.3 and thence thru intake valve 38 fitted into opening 39 back to the chamber 12a.

It will be apparent that valves 23 and 38 are of the spring controlled type and may be set to open and close at such times as the piston I moves up and down within the cylinder [2. I have found that with a piston stroke of somewhat less than A2" (governed by the eccentricityof member I 8) and a motor turning at about 1720 R. P. M. I can secure an air flow up to 2 cu. ft.

per minute at very low head pressures (no loadconditions). With these constants the pump will operate most efficiently, however, under load conditions calculated to give a pressure of from about 5 to 8.lbs. per sq. inch, producing, at these pressures, a constant and uniform flow in the neighborhood of 1% cubic feet per minute. With the above brief description of the con struction and operation of the illustrative device I shall proceed to a more detailed description.

The piston assembly may be very simply constructed, as shown in Figure 2 by attaching bearing I! to the connecting rod by fitting the bearing snugly within the opening provided at" the lower end of the rod and snapping it in place by snap rings 40. Eccentric I8 is suitably connected to the inner race of bearing I1 and is secured to shaft l9 by a'key 4| in suitable keyways. Shaft I9 is preferably intervally threaded to provide for locking the eccentric or cam structure in place by bolt 42.

The upper end of connecting rod 16 has secured thereto by bolt 44, the piston follower l4. follower may be threaded to the rod as at 45. Cap 46 fitted over soft washer 41 and provided with lock washer 48 may be conveniently provided to lock the assembly together, suitable recesses 49, 50 provided in members 14 and 46 in order securely tohold the bead 5! on diaphragm l5 and to form a fluid-tight connection.

The top of compression chamber l2a formed by partition l3c of head. I3, is arched as shown in Figures 2, 4 and 5 and is of such contour as to follow closely the upper contour of the structure I5, 46 when the piston is at the upper limit of its, stroke, but sufficiently spaced therefrom to permit the edges of the cap 46 to clear the top of the arch as it inclines before and after the maximum upper limit of the stroke is reached.

Partition |3a is recessed at 53 and cylinder block Illa has a complementary recess 54 into which' are fitted bead 55 of diaphragm 15 in order to form a sealed fluid-tight joint.

It will be noted that the diaphragm 65 in the construction shown serves the three-fold purpose of forming the working surface which compresses the air, acting as a bearing for the upper end of the piston assembly, and of sealing the pressure side of the system. More than this, the structure obviates the necessity of a wrist pin between the connecting rod and the piston.

The valves 38 and 23- may be substantially similar although of course each one works in a direction opposite to that of the other. Exhaust valve 23 is typical and is shown in Figures 6 and '7. It comprises a casing 58 containing a ring 59 which positions a spider 6|] the center of which secures a spring 6| attached to valve 82' cooperating with valve seat 63. Lip 23a is conveniently swaged down to retain'the valve structure within casing 58. Egress from chamber I2a is had thru opening 64, over the valve seat and up thru openings 65, the pressure in chamber I2a causing the valve member 62 to lift against the pressure of spring 6| upon the up or working stroke of the piston I5. Valve 23 may be threaded in opening 22 as shown in Figure 2. 4

Valve 38, threaded in opening 39 is mounted oppositely to valve 23 in order that it may close I on the up stroke of the piston and open as the block Illa.

struction shown permits easy access to the diapiston moves down.

Both the cylinder block Illa and the head l3 are partitioned as shown in order to provide the passageways and chambers previously described.-

phragm I5, valves 23 and 38, pressure release 15. etc. in the event servicing is required in the field by inexperienced personnel.

Head I3 is preferably formed with fins 14 as shown in order to enhance cooling of the The Y same by external air. Within the head is removably secured an adjustable constant pressure valve 15 in the manner shown in Figure 2. The

valve is mounted as by bolts 16 against the upper recess H of head l3, which recess communicates with chamber 24 by openings 18 and 19. A diaphragm extends across recess 11 and is secured in place by the pressure of member 8| against the seat 82 in head l3, the diaphragm seating upon seat 83 of nipple 84. A spring 85 secured to disc 86 and supporting member 81 maintains a selected pressure on diaphragm 80, the spring support 81 being carried by threaded shaft 88 in the uppermost part of'member 8|. Adjusting nut 89 is provided and is preferably protected by cap 90.

It will be apparent from the above described,

structure that when the pressure within chamber 24 exceeds that set on spring 85 by nut 89 the diaphragm 80 will be moved upwardly and the pressure within chamber 24 released thru opening 19 into the low side of the system, thus up in the cylinder head, thus overloading the motor and otherwise creating hazards, the safety valve simply by-passes the excess pressure to the low side of the sealed system, maintaining the total quantity of dry air within the system.

The adjustable constant pressure valve I is integrally formed within the cylinder head and promotes simplicity of design, saving of space and the elimination of outside fillings and lines.

A filter 92, as shown in Figure 1, may be removably located within casing 30 and may consist of a screen 93 containing a suitable dessicant 94 such as plaster of Paris. The screen may conveniently beinserted within the casing 30 and held in proper position by' shoulder 95 seated in openingSG and held in place by bushing 91 having a flange 98 held against lugs 99 bybolts I00, lugs 99 being secured to casing 30. Gaskets IOI, I02 and I03 may be provided to maintain the system fluid tight. An opening N4 in bushing 91 communicates with conduit 29 and guides the air into the the screen 94.

In 'order that the air within the system may front end (not shown) of be maintained at a substantially constant tem-' perature I may provide at a suitable place therein, for instance between the exhaust conduit 3i and the mechanism to be driven by'the air flow .(see Fig. 3) a heat controlling device generally indicated at I09 containing one or more electrical heaters I05 connected to a source of electric power I06 thru a thermostatic switch I01, adjustable at IIO, for instance of the well-known bellows type having an element I08 whichis sensitiveto temperature and which upon cooling will contract a liquid within the bellowsand cause a contact to close, thus energizing at least one heater circuit. When the air within the sysdesirable to keep the-air which acts as the motive power at fairly high temperatures such as 100-150 F. Accordingly the provision of a controlled heating device of the nature described,

in conjunction with a sealed system containing dry air, is of particular utility in insuring that these temperatures and conditions are maintained and the operation of the turbine maintained at substantially uniform speeds.

In order to follow the operation of the system I may provide within the casing I0 a pair of gauges H0 and II 'I connected respectively to the high and low pressure sides of the system, as by connecting tubes II! and 3. It may be desirable to ensure that'the pressure within crank case I0 be allowed to equalize with the low side of the system and for this purpose a small hole 43 may be provided (see Fig. 2). This prevents the possibility..of ,inaccurate readings on gauges I I0 and III on account of increase in pressure in crank case I0 due to temperature rises.

It should be noted that-the passages and chambers 24, 25 and 26- are integrally formed in the cylinder head and block and are of sufiicient volume to act as surge tanks, in the high or pressure side of the system, thereby damping out pulsations and permitting uniform air flow.

Within the casing I0 may also be provided accessory equipment such as a transformer H4, fuses and connections (not shown) and a switch II5. This provides an air-tight, water-tight and explosion-proof space for such equipment, which is of distinct advantage in connection with the air turbine and the device or devices driven thereby and obviates the necessity of separate protective casings for the accessory equipment. H5 is a terminal for bringing power. into the transformer thru a plug connector (not shown) and II! is output terminal connection for taking out different voltages, say and 6, thru a plug I connector, (not shown). A cover IIB removably secured against a, gasket II9 by bolts I20 may conveniently be provided for maintaining the interior of casing I0 fluid-tight and for obtaining access thereto. A switch handle I2I is, shown for actuating switch H5.

It will be understood that the invention has been described in connection with an illustrative embodiment and that many modifications,

adaptations and changes in the structure shown maybe made as will be apparent to. those skilled in the art, without departing from the spirit of the invention.

Having thus described my invention, I claim:

1. A pumping system comprising a cylinder block, a cylinder head, a crank, a flexible diaphragm secured between said block and head, a piston follower secured centrally of said diaphragm, a connecting rod fixedly secured at one end to said follower and pivotally secured at the other end to said crank, said cylinder block and head containing-passages in the high or pressure side of the system, said passages being integrally formed therein, and serving as a surge tank to ensure the smooth flow of fluid through the system.

2. An hermetically sealed pumping system comprising, in combination, a reciprocating pump. comprising a piston, piston actuating means, a cylinder block and a cylinder head, said piston comprising an annular flexible diaphragm. having beaded peripheries and a pair of members securely clamping the interior head of said diaphragm, the cylinder block and the cylinder head cooperating securely to clamp the exterior bead of said diaphragm, accessories including a gauge and a switch, said cylinder block having an hermetically sealed chamber therein, said accessories being housed therein whereby said system is maintained water-tight.

3. An hermetically sealed pumping system comprising, in combination, a reciprocatin pump comprising a piston, piston actuating means, a cylinder block and a cylinder head, said piston comprising an annular flexible diaphragm having beaded peripheries, a pair of, members securely clamping. the interior head of said diaphragm, the cylinder. block and cylinder head on said block and dogs on said lugs whereby said cylinder head may be removed and easy access to said piston may be had.

JOHN w. CRAIG.

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