US2571575A - Steam cleaner - Google Patents

Description

l Oct. 16, '1951 J. C. HOLMES STEAM CLEANER 5 Sheets-Sheet l Filed July s, 1947 ,I l ,Ulf

umnlllmumlmmlMaxxum||||||| l vom/1 fwn Oct. 16, 1951 Filed July 3, 1947 .1. c. HOLMES STEAM CLEANER 5 Sheets-Sheet 2 Ey? 8 s INVENToR. JT @.HOZME/S' M4/Mw ATTORNEYS Oct. 16, 1951 Filed July 5, 1947 Fig. .Y

J. C. HOLMES STEAM CLEANER y 5 Shfaer,-s-Shee1I 3 Fig. 4

I N V EN TOR. ,f c. HMM/4&5

ATTORNEYS INVENTOR. J CZHOMS ATTORNEYS Oct. 16, 1951 Filed July 3, 1947 Oct. 16, 1951 J.' c. HOLMES STEAM CLEANER Filed July 5, 1947 5 Sheets-Sheet 5 @w FII 7 12 Fyyl/ 10 114 12o I 115 107 y Syvum/vtm Fly 9 116 JF CUYOLMES Patented Oct. 16, 1951 UNI TED STATES QF FI C v2,571,57 5

sjrEAM CLEANER John C. Holmes, Signal Mountain, Tenn. Application July 3,v 1947, Serial No.

This invention relates to cleaning equipment .using-cleningfuid v'discharged from a `nozzlek at .my inventiom. no .provision hasbeen made` for providing hot air to dry ofi the parts after they ,are cleaned. For instance, in steam cleaning Vautornobilemotors and chassis to remove the heavy- ,1i-lm' off grease `the entire motor Vwill be- .comeV enveloped in acloud of steam. y The present kinvention provides apparatus with which it is possible to immediately yblovv all. ofthe moisture awa-y: from. thesurfaee after-,i12 isleane and also; tolsupply hot, dry air for the 'purpose of .completely drying thesurface. yAlsor the apparatusis provided with the necessary controls so that anyj degree of mixture of air and water may loeobtained at` the desired temperature so` that vuidl may be varied progressively from hot, v dry air:v dry Steam; wet-.Steam t 110i .and Warm water mixed With the desired amount of detergent or cleaning agent. Also the pressurecan be controlled so tlrat ifv desired all of vthese fluids o can be supplied athigh velocity.

Accordingly, the primary object ofwthe invention. isl to. provide improved cleaning apparatus of the` above type, in which the mixture of the cleaninguid can be controlled atvvill and can be delivered. at desired temperature .and velocity tomeet any desired requirements.

Another object is to provide in such apparatus a boilerfvvhich may be used to heat the `airsteam or Water.-v

Another object is to provide such apparatus in which thesameequipment can be' used toy clean and.A dry Athe objectf to be cleaned by merech'ange of the o controls.

' Another'object is to provide such equipment in which. thenormal. .operation of equipment will serve toY self-cleanftheboiler and iiushV out any remaining moisture'- therein.

AnotherV object is1 to. provide such apparatus in which it is possible to add air pressure'to the cleaning Vjluid jstream either beforeor` after it epasslesith'rough the` heating means.

11 Claims. (Cl. 299-83)v .anism to prevent excessive pressures or Another object of invention is to provide steam cleaning apparatu'shwith means for applyingthe steam at a pressure in excess of the Water pressure.

A further object iste provide cleaning apparatus in which thecontrol o f the Water or steam at the nozzle is controlled on the inlet side to the boiler.

'A stillA further object of invention is to provide apparatus of thetype described with novel means forsup'plyingv the necessary" pressure to resist the steam ,pressure in the boiler.

A further object 'isto provide a novel'pneumatially-operated pumpfor automaticaliy vvvproducing the necessaryloack-pressure for the boi-ler of cleaning and'washing apparatus of thei'type described.

A Ystill further object is' toprovide a novel pneumatic 'o'or'itrol'Y mechanism for operating `the switch .controlling the electrical heating vunits ofthe -boiler and anovelcombination thermostatpressurestatattached"to one ofthe boiler Walls which' Willoperatethe-.pneumatic control mechtemperatures in the'boiler.

therand furtherA objects will become readily apparent" from' the vfollowing description when considered' in connectionwith` the accompanying dra.'\`1virigs',y 'illustrating an embodiment off the'invention, andfin Which:A

`Figf1^is a perspective View of cleaninge'quipment made i'n`.a'ccordance` with the present invention;

FigfZ' isla front-elevation With the cover remgved.; .V n

".Fi'g. 34 is. an krend'. elevation of the. left hand side of Fig. 2.

Fig. .4.is. an Fig.` 2.'

.FigA '51.is. a partial,horizontalsection online 55 ofFigf4."

Eiga.. 6` is a. 'partial'. detailsectional elevation rof Fgz:

Fig..7., is. a .partiaL sectional.. elevation of Fig. 6. fisl anfenlarged. partial'- View of.' Fig..2

elevation/of therright` hand side. of

.showing ltl'ie. -auto'n'iaticcontrol for th'ernixi'ng Fig. .9i is. a. cross sectional. Viewv of the mixing valve..K f I Eig. V10.is.acrosssectional view on line IDL-I0 ofEghg: Y,

Fig, 1`1 is an enlarged sectional detail ofthe thermostat-pressures'tat devicefor. ,automatically releasing"thelpovvercontrol'device. Y

Broadly speakinggfthenovelty of the present invention resides in the provision o a boiler to which water and/or air may be supplied in the proper ratio to produce a cleaning medium which may be supplied to a mixing chamber where a suitable detergent may be added for facilitating the cleaning with the high velocity jet. As will be apparent from the following description, the mixture in the mixing chamber is delivered through a hose or pipe to the discharge nozzle. One of the advantages of this arrangement is that the ingredients of the cleaning medium become homogeneously mixed before being discharged from the nozzle. Another important feature of the invention is the provision of a suitable booster pump which resists the back pressure of the steam pressure in the boiler and will operate automatically in response to the controls to deliver the cleaning medium at the nozzle at the desired pressure. Suitable control valves are provided so that the cleaning medium discharged from thedischarge nozzle may be:

(a) Hot water;

(b) Steam;

(c) Air and steam;

(d) Air and hot water; and (e) Hot air Means also are provided so that the yabove medium-elements may be delivered at the nozzle either with or without any desired detergent agent.

The form of the invention chosen for the purpose of illustrating the invention, comprises a boiler I; main control valve 3 and air control i valve 33; mixing chamber 6; suitable detergent receptacles 1 and discharge nozzle 8; and a suitable booster pump 2 for supplying necessary water against pressure, together with the necessary conduits to make this an operative device. All of the mechanism is arranged within a suitable housing 9, supported by a suitable frame I|, mounted on suitable casters I5 to facilitate the movement of the apparatus over a floor.

For purpose of clarity, it is believed that it,

will be best to trace the conduits for` the water, air and detergent agents so that the subsequent description will be more easily understood. A suitable water connection I3 is provided which may be connected to any suitable source of water under pressure, such as the usual city water supply, through a flexible hose (not shown) This water supply to the boiler may be controlled by a master water valve |4. The water connection I3 is connected to the booster pump 2 through suitable conduit pipe I6 to the water inlet manifold I1 at I8. The water pressure at the inlet I8 will be indicated on the pressure guage 20 which is connected to the pipe I6 by means of the conduit 25 The water outlet manifold I9 of the booster pump 2 is connected through suitable pipe 2| and valve 3 to the bottom of the boiler I at the point indicated by the numeral 22. The pressure in this pipe 2| is indicated on guage 23 which is connected by a suitable conduit 24 to the pipe 2|. Aiter the water is passed into the boiler I, it may be converted to steam or merely warmed, depending upon the rate at which the Water is supplied to the boiler. Also, as will be explained later, if air is admitted to the inlet of the boiler, some air may be mixed with the water or steam. Alternately, air only may be suD- plied to the boiler where it may be heated. The outlet from the boiler I is connected by a suitable pipe 26 to the mixing chamber 6. As will be 'readily apparent, the mixing chamber 6 is con- 4 nected to the nozzle 8 by means of a ilexible hose 21.

A suitable air connection 28 is provided for connecting the cleaning apparatus to a suitable source of air pressure such as that usually available in a garage. This air inlet 28 is controlled by suitable master valve 29 and is. also connected to the three-way main control valve 3 by means of a suitable conduit 3|. This air connection 28 is also connected through the pipes 32, air valve 33 and pipe 34 to the mixing chamber 6. The air pressure supplied directly to the mixing chamber 6 will be indicated on the pressure guage 36 which is connected to the pipe 32 by suitable connection 31. It will be understood that the valve 33 controls the air supplied through the pipe 34 directly to the mixing chamber 6.

As shown in Figure 5, the mixing chamber 6 is provided with a Venturi throat 38. The air pipe 34 is connected inside the chamber to a cylindrical tube 39 which terminates at the narrowest part of the Venturi throat. The high velocity air issuing from the tube 39 expands in the throat and tends to create lowered pressure at that point. Water, air or steam or a mixture of all three which enters the mixing chamber through the pipe 26 will have a high velocity as it passes through the Venturi throat. Advantage is taken of the suction of the Venturi throat to draw a detergent into the mixing chamber from which it can be supplied to the nozzle 8. To this end, a conduit 4I is connected to the back side of the mixing chamber and to the detergent manifold 42. The manifold 42 has connected thereto suitable branch pipes 43 which extend into the different detergent containers 1. Communication is provided between the pipes 43 and the manifold 42 through suitable manually operated valves 44. As will be readily apparent, different kinds of detergents may be put in the different containers 1 and the individual valves 44 may be operated as desired to permit the desired amount or ratio of the different detergents to be drawn into the mixing chamber 6 bythe action of the Venturi throat 38. Since there is a large number of detergents which may -be used, if deemed desirable it will be rather apparent that additional containers could be supplied and connected in a manner similar to those shown to provide a larger variation in the detergents for facilitating the cleaning action.

The boiler is of the progressive heating type and includes a series of units Ia comprising a series of tubes or pipes lying one above the other. The opposite ends of the pipes or tubes are connected together by suitable conduits Ib. The conduits Ib are aligned so that the water or steam in the boiler xnay readily pass from the bottom to the top of the boiler. Although it will be readily understood that other means of heating may be used, in the particular embodiment illustrated in this specification, the individual units |a of the boiler are provided with electrical resistance heating units 46. These units are of conventional construction of the enclosed heater type in which the heater resistance, per se, is surrounded by suitable insulation and is hermetically sealed inside an outer metallic shield of high heat conductivity. A plurality of heat conducting ns 41 may be arranged transversely of the metallic shield and in thermal contact with the latter. As shown in Figure 3, the individual heater units 46 of the different boiler units la are connected in parallel to bus bars 48 which may be energized through a suitable electric connection 49 with'a on piston 54 causes the piston 54 to inove downwardly until it contacts the piston block 13 moving it down to its lowermost position. As explained above, the movement of the piston block 13 operates the slide valves 68 and 69 and the downward movement of the block 13 .through the bell crank toggle mechanism 16, 11 and 18 moves the valves 68 and 69 -to the right as viewed in Figure 6, whereby valve 69 will uncover port 61 allowing air to enter through 'bore 63 to the lower part of cylinder 52 against the bottom'ofl pneumatic motor piston 59. A't the same time valve 68 has also moved to the right, uncovering port 66 in the bottom of cylinder 5|, allowing the air under piston 56 to escape through the other end of bore 63 to exhaust. The air pressure in the bottom of cylinder 52 under piston 59 forces the latter upwardly until piston 59 contacts block 13 moving the latter to its uppermost position. This action reverses the valve action, moving it to the left causing valves 68 and 69 to move to their other extreme. position, exhausting air under piston 59 through port 61 and at the same time allowing air to enter cylinder through port 66. The construction arrangement is such so that the pump operates only when the Iwater admitted to the inlet manifold of the pump 2 is sufcient to move the pump pistons downwardly.v In this respect the automatic operation of the pump is operated by adjustment of the valve 3. If, for instance, valve 3 is closed, no water can pass into the boiler and air pressure on the pistons 56 and 59, whichever one is on the upward stroke, due to the position of valves 68 and 69, remain stalled and no movement of the pistons takes place until water is allowed to flow through valve 3. If valve 3 is open all the way, as is the case when it is desired to deliver hot water, the pump remains stationary, due to the fact that there will not be sufficient resistance to check the ow of water to develop suicient pressure on the pistons 53 and 54 to operate the latter. Consequently, the water will flow through the water inlet and outlet manifolds of the pump 2 into the boiler, mixing chamber hose and nozzle without any added pressure being developed by the pump. In some cases where air pressure does not exceed water pressure to any great extent, it may be desirable to install a piston block in cylinder 5| similar to the piston block 13 in the cylinder 52 and to connect such additional block to the bell crank mechanism in such a manner as to take advantage of the water pressure on piston 53, pushing it to its lowermost position while air is applied to piston 59, moving the latter to its uppermost position. In so doing, the pump would operate whenever water was passing through valve 3 whether it is in steam or Hot water position. The pump will then operate at any time that the water pressure on either of the pump pistons 53, 54 is suilcient to move the latter far enough to operate the valves 68, 69.

It will be obvious -that the electrical control switch 50 may be manually operated. However, in order to prevent damage to the boiler and the electrical resistance units by reason of possible overheating through neglect or carelessness of the operator, means is provided for automatically opening the switch in response to excessive temperature or pressure in the boiler. To this end,

' a pneumatic cylinder |0| is suitably pivoted to the frame at |02 and the piston rod is connected at |03 to a suitable arm |04 which in turn is secured to a disk 'or wheel |06 on the shaft which operates the switch 50. v As will be apparent from the previous description, a source of air` pressure must ,b'e "available to operate the 'steam cleaner 'and this same source is used to operate the pneumatic cylinder. The admission of the air to the cylinder |0| is controlled by suitable three-way air valve |01 and push button air valve |08. As will be clearer from the following description, the air valve |08 admits air to the pneumatic cylinder |0| to operate the switch and the air exhaust valve |09 may be manually operated to exhaust the air from the pneumatic cylinder to permit a suitable spring ||0 to return the switch 50v to the Off position. An additional air exhaust valve ||2, supplemental to air valve |09. is responsive to the excessive pressure or temperature in the boiler, is provided for automatically releasing the air from the piston |0| to provide a safety control for the boiler.

The three-way air valve |01 is connected through suitable pipe ||3 to the source of air pressure used for the operation of the cleaning mechanism of this invention. The pipe ||3 is divided into two branches, ||4 and ||5. The branch |4 is connected directly to one side of the valve |01 while branch ||5 through the air control valve |08 is connected to the opposite side of the valve |01. A suitable pipe or conduit I |6 connects the valve |01 to the base of the pneumatic cylinder |0|. Conduit ||1 is connected to the conduit ||6 between the cylinder |0| and the valve |01 and through'the air control valve |09 provides means for bleeding the air from the cylinder |0|. As previously mentioned, the valve |09 is adapted to be manually operated. A second branch conduit ||8 also connected to the conduit ||6 communicates with the air release valve ||2 which is operated by a combination thermostat-pressurestat |2| in response to excessive temperature or pressure in the boiler to exhaust the air from the cylinder |0|. When valve |08 is depressed, air can ow from conduit ||3 through conduit ||5 throughthe valve |01 to the base of the cylinder |0|. A suitable mechanical connection is provided between the arm |04 and the valve operating arm ||9 of the valve |01 so that when air is admitted to the base of the cylinder |0|, causing the arm |04 to rotate in a clockwise direction, the valve arm I9 will be rotated with it so that communication between the conduit ||5 and the valve |01 is cut off. As will be readily apparent from Figure 8 the air from conduit ||3 can ilow directly into the opposite side of the valve |01 through the conduit ||4. It should be noted here that a suitable reducer disk |20 having a very small opening therein is provided in the conduit |04 to reduce the air flow into the valve |01. This restriction becomes very important as will be understood later in connection with the release of the air from the cylinder |0| for returning the switch 50 to its Off position. When the piston in cylinder I0| has been moved through its full stroke under the influence of air pressure, the valve |01 will have moved to such a position that communication with conduit ||5 is completely closed. It will be readily apparent that by reason of the reducer disk |20 that the piston in the cylinder |0| will have very slow movement. When the piston has traveled to its outward limit, the switch 50, through suitable snap action mechanism (not shown) will have moved to the On position and will be held in this position as long as air pressure remains on the piston in cylinder |0|. In this position the valve |01 will be in such a position that the conduit ||4 is directly in communication with the conduit ||6. If the operator wishes to cut off the electric` current to the heater, he merely has to depress the air control valve |09.' This exhausts the air in cylinder |I to the atmosphere. Due to the fact that the opening in the valve |09 is larger than the opening in the reducer disk |20 in the conduit IIll, the pressure in the cylinder |0| will be greatly reduced so that the spring I0 will rotate the disk |06 to return the piston to its innermost position. It will be readily understood that at the same time this movement of the lever |04 to the Off position turns the valve operating arm IIS of the valve '|0l" to its original position so that air is cut off from the conduit IIB. Of course, the hydraulic piston mechanism can again be operated by depressing the air control Valve |08. If, for any reason, the air supply fails or drops in pressure sufficiently to preclude the proper operation ofthe cleaner, the spring ||0 will pull the lever |04 to the Off position. The operator will then have to again depress the air valve I 08 in order to close the electrical switch 50. In order to avoid extreme temperatures ofthe heating elements where the operator is heating air for drying off work and operates the machine for a long period of time, which may damage the elements or shorten the life of the discharge hose, a combination thermostat and pressurestat |2| is installed in any suitableposition in the. wall of the boiler. This device is adapted to operate on a temperatureof approximately 500 degrees or a pressure, of approximately 150 pounds per square inch. Of course, if desired the device could be designedor adjusted to. operate on other desirable temperatures .and pressures. This unit comprises ahousing |26 which maybe screwed into the side ofthe boiler or may be securedA thereto by welding.r In the form illustrated the housing |26 is cylindrical and threadedly .engages an .internally threaded cylinder .welded to a wall of the boiler I. Inside `of thishousing .I 26 is an outer bellows |27, one end of which is suitably sealed toa disk |2611 held by a cap. I 2Gb on the outer end of housing I 26. The inner endof, the outerbellows I2'I is suitably sealed to a disk |28 which seats on a ledge in housing |26., This diskis provided with a suitable aperture as shown so that the relative movement .ofA disks |2ia and |23 will not be retarded by any fluid which might be trapped therebetween. A second inner bellows |29 is provided with its outer end sealed to the disk IZSa and its inner end sealed to an actuating stem |30. It will be readily understood that, if desired, the two bellows could be made in one unit with the bellows |29 inside ofthe outer bellows |21. The intervening space'between the walls of the inner and outer bellows is filled with a fluid having a suitable thermal expansion characteristic. The inner end of an actuating stem |30 is adapted to rest normally against a boss |3| carried by the disk |28 and the other end protrudes through a central aperture in the disk |2311; An extension |32 is adjustably threaded on the outer end of the stem |30 and may be locked in position by a suitable lock nut |33. TheVp-urpose of the adjustable extension |32 is to provide means for adjusting .the effective length of the stem |30' for varying the temperature or pressure at which the device opens the air valve I I2v to release air from. cylinder |0I. The end ofthe stem is arranged adjacentV the air Valve ||2 so. that if the stem |30 is moved outwardly of the housing |26, it will operate the valve |2.to exhaust any air in the cylinder IOI. i i

Because of the thermal expansion characteris- .'15 the pipe 4 I.

tics of the fluid between the two bellows, an excessivel temperature rise in the boiler 2| will cause the fluid to expand the inner bellows |29 and move the stem |30 outwardly, thereby actuating the Valve ||2. If, on the other hand, the temperature does not become excessive but the pressure in the boiler becomes too high the outer bellows |21 will be compressed and the stem |30 will be forced outwardly to actuate the valve ||2 permitting air to escape from the cylinder |0I. The adjustable extension |32 makes it possible to set it for various temperatures or pressures.

supposing the operator hasbeen heating air for a considerable .period of time, and the heating elements. and boilers` are at a very high temperature but not high enough to release the switch, he may turn the main valve to hot Water. This action will cause steam to generate quickly; much faster than the discharge nozzle will allow it to escape, and this pressure rise would cut off the switch immediately and no harm would rbe done, The operator could not turn on the current even if he wanted to until the pressure was reduced to normal. This same thing could happen if the discharge hose became clogged up. In case the operator should turn on the current without having water or air owing through the boiler, the sudden temperature rise would cause the release of air pressure in the cylinder 0| and cut oif the electric current.

If the operator wishes to clean the grease and dirt from an automobile motor or chassis, .the operator starts the operation of the cleaning equipment with the electrical control switch `50 in the"O1f position. The main Valve 3 is turned to the Hot water position and is allowed to re.- main until the water ilows in a steady stream from the discharge nozzle 8. This to insure the boiler is'lled with water. Then the main valve 3 is turnedA to the 01T position and the control switch 5,0 is turned on. Within a brief interval steam will be discharged from the discharge nozzle 8 and the pressure in the boiler I will begin to riseas indicated on the steam guage 23. The main valve 3 is then turned -to the Steam po.- sition, which is about ninety degrees in an anticlock-wise direction from the 01T position. When Ythis Vlave isin this position, a small amount of water is allowed to enter the boiler and is converted -to steam. The steam pressure will gradually increase and remain fairly constant, fluctuating slightly due to the moisture content of the steam. This moisture isY desirable and may b e adjusted by moving the main Valve 3 slightly to the right or left `of the Steam position. By opening the valve farther to the approximate degree position, the amount of water entering the boiler will be suflicient to prevent the generation of steam and the water will merely be warmed or heated. The control can be varied to vary theY temperature of the water. Farther opening of the main valve 3 to the 270 degree .position shuts off all the water allowing air only to enter the boiler, displacing all the water and thereby producing hot air. Any solution or combination of cleaning solutions or detergents may .be add,- ed to the steam, water, or air being discharged from the nozzle 8 by adjusting one or more v,of vthe valves 44 to produce the quantity suitable for`the'best results. It will be understood that when any one of the valves 44 are opened the suction created in the Venturi throat 38'of the mixing chamber 6 will draw the cleaning solution or detergent from the glass containers through After the motor or other object has been cleaned with steam and the desired cleaning solution, the valves 44 will be closed and the main valve 3 will be turned to the Hot water position. This will have the effect of tremendous steam pressure discharging from the nozzle 8 due to the over-supply of Water coming into contact with the heating elements and in so doing it flushes out the detergents and flushes out any foreign ingredients from the boiler and discharge hose. This condition is of short duration and is `then followed by clear hot water. After the article has been washed with steam and the cleaning solution and rinsed with hot water, the article may be immediately dried with hot air by turning the main valve 3 to Hot air position. Hot water is then driven from the boiler through the discharge nozzle 8 and is displaced by a stream of hot air which is heated as it passes through the boiler l. This is a particularly advantageous feature of this invention where, it is desired to steam clean automobile motors and immediately dry all of the ignition wires, coils, etc.

When it is desired to wash the painted surfaces of an object such as 'an automobile body and wheels, a procedure similar to that described above is followed except that when using steam it may be desired to cool the steam somewhat in order not to damage the painted surface. This may be done by opening the air valve 33 and adjusting to the desired temperature. This allows cool air to by-pass the boiler I directly into the mixing chamber 6 to thereby increase the effectiveness of the washing procedure both by providing greater pressure and by more thorough mixing of the cleaning solution with the moisture. It is possible for the operator to have at will almost any combination he desires to meet the conditions encountered. The device may also be used for flushing out radiators and motor blocks of automobiles. In such case the special cleaning agents or detergents to be used would be those particularly effective in dissolving or loosening the rust scale inside radiators and motor.

Although the present invention has been speciflcally described with reference to a specific embodiment, it will be readily apparent that the exact arrangement shown is not absolutely essential so long as the basic elements are used in combination with the necessary controls. However, there are certain specific features of the present equipment which contributes to the overall efficiency of the equipment. For instance, it will be noted that all the ingredients are mixed in the mixing chamber 6 and are then delivered to the high velocity nozzle 8 through the flexible hose 1. The flexible hose 1 facilitates the further mixing of the ingredients and since its inside diameter is greater than the orifice in the nozzle 8, high velocity discharge is produced at the end of the nozzle. This system is distinguished from some of the prior devices in which the ingredients are mixed at the point of discharge from the nozzle. Another novel feature of this invention is the provision of the special handle 9| which is attached to the hose 21 by separable brackets 92. The handle 9| is provided With a special Bowden wire control 93 which is connected to a boss 8a on the nozzle =8. The Bowden wire is provided with a small button .94 by which the operator can change the direction of the nozzle by pulling back and forth.

Cil.v

, 12 special booster pump 2 which operates only when it is necessary to supply desired increase in pressure in response to the control valves. i It pro- Vides a Very simple and efficient construction and since it only operates when it is needed it is not necessary to run continuously 'as is true in other equipment now on the market.

From the foregoing explanation it will be apparent that the pump provides a back-pressure for the boiler dependent upon the pressure of the water source or the source of compressed air, whichever is the greater. In other words if the water pressure was suflicient the pump would never have to operate.

The novel combination thermostat-pressurestat |21 is so arranged that a double safety feature is provided not only for the boiler itself but for the heating units. The device will be operated either by excessive pressure or temperature.

Although the invention has been described in considerable detail, it will be apparent to those skilled in the art that many variations are possible without departing from the inventive concept. It is therefore desired that the invention not be limited except insofar as is made necessary by the prior art and by the appended claims.

What I claim is:

l. Cleaning or washing apparatus having a series fluid path comprising a boiler, means for connecting a source of' water under pressure to a common input orifice for said boiler, independent means for connecting a source of compressed air to said input orice, a mixing chamber, means for connecting the outlet of said boiler to said mixing chamber, a high velocity discharge nozzle separate from said mixing chamber, conduit means for connecting said mixing chamber with said nozzle said boiler forming a fluid conduit interposed in the fluid path between said common input orifice and said mixing chamber for imparting heat to the water and compressed air coupled therethrough, and valve means intercoupled between the means for coupling the compressed air and water to said common orifice for selectively controlling the fiow of air and water therethrough, whereby said valve means may be adjusted to supply either steam, hot water, a mixture of air and steam, a mixture of air and hot water, and hot air only to said discharge nozzle.

2. A washing and cleaning apparatus having a series fluid path comprising a high velocity discharge nozzle, a mixing chamber, a conduit connecting said mixing chamber and said nozzle, a flash boiler, means connecting said mixing chamber and said flash boiler, means for connecting a source of water under pressure to a. common input orifice for said boiler, independent means for connecting a source of compressed air to said input orifice, said boiler forming a fluid conduit interposed in the fluid path between said common input orifice and said mixing chamber for imparting heat to the water and compressed air therethrough coupled, and valve means intercoupled between the means for coupling the compressed air and water to said common orifice for selectively controlling the flow of air and water therethrough, whereby said valve means may be adjusted to supply either steam, hot water, a mixture of air and steam, a mixture of air and hot water, and hot air only to said discharge nozzle.

3. Method of controlling the detergent characteristics of a iiuidr used in an apparatus forl cleaningv grease, dirt and the, like from anyarticle,

comprising the step of supplying air andfwater in selected quantities independently and each underipressure to a common conductor, coupling 'said air and water. from saidconductor through a heated conduit, discharging the resultant fluid from said heated conduit to a mixing chamber, maintaining sufficient velocity in saidA mixing chamber so asito injecty by suction an additional detergent agent and delivering said resultant fluid from said mixing chamber through a nozzle in a high velocity stream.

4. In a process for cleaning an article by the detergent action of a high velocity fluid which comprises the step of supplying air and water in selected quantities independently and each undery pressure to a common conductor., coupling said air and water from said conductor through aheated conduit, discharging the resultantiluid from said heated conduit to a mixing chamber, delivering said resultant fluid from said mixing chamber through a nozzle in a high velocity directive stream and controlling the detergent and drying action of said cleaning fluid by adjusting the relative amount of water and air supplied to said heated conduit.

5. In combination in a washing and cleaning apparatus, a boiler, means for coupling a source of `water under pressure to said boiler, independent means for coupling a source of' air under pressure to said boiler, a pump for continuously delivering water to said boiler, valve means between the means coupling water and air to said boiler for selectively controlling the flow of water and air entering said boiler, said pump comprising a cylinder, a piston assembly, including a pump piston in said cylinder and a pneumatic motor piston in said cylinder adapted to operate said pump piston, valve means responsive to movement of said piston assembly for controlling the operation of said pneumatic piston, the pump piston end of said cylinder adapted to be connected to a source of water under pressure, the pneumatic motor end of said cylinder being coupled to a source of air under pressure to operate said pump piston in response to a pre-determined pressure differential between the water pressure on said pump piston and the air pressure on said pneumatic motor piston.

6. A cleaning or washing apparatus of the type described having a series fluid path comprising a boiler, means for connecting a source of `water under pressure to a common input orifice for said boiler. independent means for connecting a source of compressed air to said input orice, a mixing chamber, means for connecting the output of' said boiler to said mixing chamber, a high velocity nozzle separate from said mixing chamber, conduit means for connecting said mixing chamber with said nozzle, a pump between said source of water and said common input orifice, said boiler forming 'a fluid conduit interposed in the fluid path between said common input orices and said mixing chamber for imparting heat to the Water and compressed air coupled therethrough, and a valve means intercoupled between the means coupling water and air to said boiler for effecting the control of air and water to said boiler, whereby said valve means may be adjusted to supply either steam, hot water, a mixture of air and steam, a mixture of air and hot water, and hot air only to said discharge nozzle.

" 71. Acleaning or washngapparatus ofthe type described, comprising a boiler, a high velocity dis-' 'charge nozzle, Va mixingV chamber, conduit means connecting said mixing chamber and said nozzle, conduit means connecting said mixing chamber and said boiler, means for connecting asource of water under pressure to the inlet loi' said boiler, independent means for connecting 'a source of compressed air to the inlet of said boiler, valve means intercoupled between the means coupling water and air to the inlet of said boiler for controlling the amount of WaterV and air entering said boiler, and means controlled by the comparative pressure of the source of iwater and the source of compressed air for developing a back-pressure to resist the pressure developed in said boiler.

8. A washingy and cleaning apparatus of the type described comprising a boiler, means for connecting the input of said boiler to a. source of water under pressure, independent means for connecting the input of said boilerto a source-of compressed air, Valve means intercoupled between said means connecting the input of the boiler to the water and air for controlling the relative amounts of air or Water entering said boiler, and pump means intercoupled between said means connecting water and 'air to said boiler inlet and responsive to the comparative pressure of said source of water and the source of compressed air for maintaining a desired backpressure from the water supply to said boiler.

9. A washing and cleaning apparatus of' the type described comprising a boiler, means for supplying water to the inlet side of said boiler, a source of compressed air connected independently to the inlet side of said boiler, a pump between the source of water and the said inlet side of said boiler, valve means intercoupled between said means supplying water to the boiler inlet and the compressed air connection to said boiler for controlling the relative -amounts of air and water entering said boiler, said pump being intercoupled between said means connecting water and air to said boiler inlet and responsive to the comparative pressure of said water source and the pressure of said source of compressed -air for developing a pressure to overcome the pressure developed in said boiler.

10. A washing and cleaning apparatus of the type described comprising a boiler, means for coupling a source of water under pressure to said boiler, independent means for coupling a source of -air Linder pressure to said boiler, common valve means intercoupled between said means for coupling water and air to said boiler for controlling the relative amounts of water and air entering said boiler to selectively supply water only, compressed air only, and desired proportions of both water and air to said boiler whereby either hot water, steam, mixtures of either `with compressed air, and hot air alone, may be selectively produced at the output of said boiler, and a pump intercoupled between said source of water and said source of compressed air responsive to the comparative pressure of said water source and of said source of compressed air and controlled thereby to supply a back pressure to the input of said boiler, dependent upon the maximum pressure of said source of water or said source of compressed air.

l1. A washing and cleaning apparatus of the type described comprising a boiler, means for coupling a source of water under pressure to said boiler, independent means for coupling a sourceof compressed air to said boiler, common valve means intercoupled between said means for coupling water 'and air to said boiler for controlling the amount of air and water entering said boiler, a pump intercoupled between said source of compressed air and said source of water, said pump having a pumping piston vand a pneumatic motor piston for operating said pump piston respectively intercoupled with the means coupling the water to said boiler and the means coupling compressed air to said boiler and being responsive to and controlled by the difference between the pressure applied to said pistons to operate said pump piston and supply a back pressure to said boiler.

JOHN C. HOLMES.

REFERENCES CITED The following references are of record in the file of this patent:

Number 18 l UNITED STATES PATENTS Name Date Black Mar. 9, Rogers Dec. 14, Blessing June 27, Fitch Oct. 2, Omick Dec. 29, Doble Aug. 19, Alexander Nov. 28, Conrader Dec. 29, Williams Jan. 5, Thompson Apr. 24, Smallhouse July 10, Busby Sept, 4, Buchet 'June 17, Paasche May 19, Weaver Mar. 8, Trowbridge June 28, Delano Oct. 5, Walters et al. Dec. 28, Martin-Hurst Nov. 30, Carlson June 13, McFarland Dec. 24,

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