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USRE27792E - Cleaning machine - Google Patents

  • ️Tue Oct 30 1973

0d. 30, 1973 C, R Howl-:Rm EVAL Re. 27,792

CLEANING MACHINE Oct. 30, 1973 Q R HOWERlN ETAL Re. 27,792

CLEANI NG MACHINE Original Filed Feb. 24, 1969 2 Sheets-Sheet 2 FIG.4

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INVENTORS CHARLES R. HOWERIN MARION W. HUMPHREYS United States Patent Office Re. 27,792 Reissued Oct. 30, 1973 27,792 CLEANING MACHINE Charles R. Howerin, 1631 NE. 57th St., Fort Lauderdale, Fla. 33308, and Marion W. Humphreys, deceased, late of Fort Lauderdale, Fla., by Mrs. Marion W. Humphreys, executrix, Fort Lauderdale, Fla.; said Humphreys assignor to said Howerin Original No. 3,605,169, dated Sept. 20, 1971, Ser. No. 801,432, Feb. 24, 1969. Application for reissue Dec. 30, 1971, Ser. No. 214,493

Int. Cl. A47l 7/00, 13/26 U.S. Cl. 15-321 3 Claims Matter enclosed in heavy brackets l appears in the original patent but forms no part of' this reissue specification; matter printed in italics indicates the additions made by reissue.

ABSTRACT F THE DISCLOSURE A cleaning machine which is particularly useful for cleaning carpets. A preferred embodiment of the machine includes a head for directing a cleaning liquid such as water or an aqueous cleaning solution onto a carpet or the like and for withdrawing soil and excess liquid from the carpet and supplying it to a chamber which contains a filter. A blower may be utilized to suck the excess liquid and soil into the chamber or tank for containing liquid. The liquid is forced through the filter, for example by means of a pump, and the filter acts to remove contaminants from the liquid. The clean liquid ows from the exhaust side of the filter through a ow circuit back to the head where it is directed against the carpet, for example as a spray. A heater is provided to raise the tem perature of the liquid so that it is very hot when sprayed, thereby improving its cleaning action. Thus, the machine involves a combination of recirculation, filtering and heating providing good cleaning and high efficiency.

BACKGROUND 0F THE INVENTION It is known to provide a type of cleaning machine which has a head through which hot water or steam is directed onto a carpet and also through which excess water or steam is withdrawn from the carpet; see for example U.S. Pats. 3,262,146 and 2,908,030. In the machine described in the former patent, a problem is encountered in that separate liquid and condensate tanks are employed in a manner which requires that the liquid supply tank be refilled relatively often. In the latter patent, recirculation of liquid is employed which reduces refilling requirements, but contamination of the liquid is a problem. The present invention proposes to employ recirculation of liquid, filtering of the liquid, and heating of the liquid to provide a highly etiicient system in which neither contamination nor refilling are substantial problems. This system also employs heat to raise the temperature of the liquid, either before or after filtering, so that the liquid as directed against a carpet is very hot, thereby promoting good cleaning action. It is believed that no recirculating hot liquid system employing a filter in this manner has been proposed, although Pat. No. 2,574,731 discloses a recirculating air system which does not employ heat nor direct filtering of liquid in the main recirculation path.

SUMMARY OF THE INVENTION One embodiment of the invention is a single tank cleaning machine having a filter mounted in the tank in a manner such that the tank can be filled with cleaning liquid such as water or a water solution to a level above the filter. A blower is used to reduce the pressure in the space above the liquid inside the tank. A pump is provided to pump liquid from the discharge side of the filter out of the tank and through a flow circuit to a head from which the liquid is sprayed onto a carpet or the like. Excess liquid and soil is sucked from the carpet by the blower and returned through a flow circuit to the space in the tank above the stored liquid. Thus, liquid is constantly recirculated. A heater is provided either in this tank or in a separate tank which is part of the flow circuit leading to the cleaning head for heating the liquid to a temperature providing good cleaning action. Where the liquid is water, the temperature may be in the vicinity of F., although the invention is not limited to this temperature range. Preferably, a portion of the liquid being pumped out of the main supply tank is tapped off from the discharge ow circuit and returned to the tank in a manner to cause the stored liquid in the tank to swirl so as to keep contaminants concentrated near the outside of the tank away from the filter, as will be described more fully hereinafter. This increases the useful filtering cycle of the filter so that it does not have to be rejuvenated or replaced as often.

The circulation of liquid from the discharge side of the filter through a cleaning head with excess liquid being returned to the intake side of the filter in a storage tank or chamber not only conserves cleaning uid, but also assures good filtering action. The heating of the liquid can be accomplished in a simple manner with this system. Filtering prevents clogging or other deterioration of the machine and allows efficient recirculation as described above. The feedback to cause swirling in the storage tank or chamber helps to increase the length of the filtering cycle before rejuvenation or replacement is required. Rejuvenation may be accomplished by the use of a second tank having an air cushion therein for forcing liquid back wards through the filter, as 'will be described hereinafter.

Accordingly, it is an object of the present invention to provide an improved cleaning machine in which recirculation, filtering and heat are employed in combination.

Another object of the invention is to provide a cleaning machine which greatly reduces refilling requirements.

Another object of the invention is to provide a cleaning machine which effectively removes contamination from a recirculation liquid.

A further object of the invention is to provide a cleaning machine in which heating of a recirculating filtered liquid can be accomplished efficiently.

Another object of the invention is to provide a cleaning machine in which feedback or bypassing of liquid is employed to increase the effectiveness of a filter.

Another object of the invention is to provide a cleaning machine in which rejuvenation of filter can be accomplished readily.

Among the other objects of the invention are to provide a carpet cleaning machine which is economical, etiicient, rugged, and capable of being manufactured on a mass production basis.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

On the drawings:

FIG. 1 is an elevational view of a two-tank carpet cleaning machine in accordance with one embodiment of the invention;

FIG. 2 is an elevational view, partly in section, of a cleaning head utilized in the machine of FIG. l;

FIG. 3 is a schematic diagram of a heating circuit for the machine of FIG. l; and

FIG. 4 is an elevational view, partly broken away, of a carpet cleaning machine in accordance with another embodiment of the invention.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

As shown on the drawings:

A cleaning machine for cleaning carpets or the like is shown in FIG. l, and this cleaning machine is a twotank embodiment of the invention. The machine 10 includes a

support base

12 mounted on floor

engaging wheels

14 which enable the machine to be rolled about as a carpet or other object is being cleaned. Mounted at the right hand end of the

support base

12 as viewed in FIG. 1 is a

tank

16 which forms a

chamber

18 for containing cleaning liquid. The cleaning liquid may be water or a solution of water and a cleaning chemical or chemicals if desired. A

filter

20 for liquids is retained in the

chamber

18, and this particular filter is a hollow, cylindrical tube having closed top and bottom ends. The filter is sufficiently porous to allow liquid to pass through it, but blocks the ow of contaminants such as dirt and other soil which may be removed from a carpet. The outside of the

cylinder

20 is its intake side and the inside of the

cylinder

20 is its discharge side. The filter is mounted relative to the chamber such that liquid can flow under pressure from the portion of the chamber on the intake side of the filter through the filter to the portion of the chamber on the inside or discharge side of the filter. A cloth filter or a filter of special material may be used if desired. The bottom end of the cloth or cloth-like portion of the tubular filter may be open to communicate with piping as shown.

It may be noted that the

filter

20 need not be cylindrical. For example, it might be a fiat disk type of filter retained transversely across the

chamber

18 with its intake side facing up and its discharge side facing down. Such a filter might be dome-shaped with the convex side directed upwardly.

The machine 10 also includes a cleaning

head

22 which is shown both in FIG. 1 and also in FIG. 2. The cleaning head has

nozzles

24 mounted in it providing a discharge flow path for directing liquid forcibly against a carpet or the like 26 as shown in FIG. 2. The

head

22 also includes a

tubular fixture

27 which communicates with a

space

28 within the head to provide a return flow path for withdrawing excess liquid and soil from the carpet 26 under the influence of suction applied to the

tube

27 as will be described. The

head

22 has a

shell

30 which is divided tranversely by a slanting

partition

32 so as to separate the

space

28 from the

space

34 in which the

nozzles

24 are mounted. The

head

22 is mounted on fioor-engaging

wheels

36, and the head may be manipulated by means of a

handle

38.

In operation, the

handle

38 may be pushed down to raise the

head

22 off the carpet 26 slightly in the manner shown in FIG. 2 so that the

head

22 may be pushed forward with the head raised. During this forward movement of the head, suction is applied but no spray of liquid is directed onto the carpet. At the end of the forward stroke of the head, the

handle

38 is raised slightly to lower the

head

22 onto the carpet, and then the head is pulled to the rear while the

spray

40 is turned on by means of a control valve (not shown) provided in the

conduit

42 connected to

nozzles

24. During this rearward stroke of the head, suction which has been applied to the

tube

27 sucks excess liquid and soil from the carpet into the tube for return to the

chamber

18.

The

tube

27 is connected to the portion of the

chamber

18 on the intake side of the filter 4t) by a flexible con- :

fuit

44. This

conduit

44 enters the

tank

16 at a

point

46 iust above the normal liquid level provided in the

tank

18. In other words, the

tank

18 should be filled with cleaning liquid to a point just below the

intake point

46. The

oonduit

44 constitutes a return liquid ow circuit for returning liquid and soil to the

tank

16. Means is provided either in this return fiow circuit or in association with the intake portion of the

chamber

18 to apply suction to the

tube

27 and to cause liquid to flow from the

tube

27 back to the tank. In the embodiment illustrated in FIG. l, this fiow producing means is a

vacuum blower

48 which may be of the centrifugal type. The

blower

48 communicales with the space above the

inlet point

46, and in operation produces reduced pressure or vacuum in the latter space so as to suck liquid and soil from the

tube

27 into the intake portion of the

tank

18.

A discharge liquid ow circuit designated generally as 50 connects the portion of the chamber on the discharge side (the inside) of

filter

20 with the

nozzles

24. In the embodiment illustrated in FIG. 1, this discharge fiow circuit includes a

pump

52, a

second tank

54, a

conduit

42 and suitable piping as shown generally at 56. The

pump

52 may have a self-contained electric motor or a separate motor as desired. The

intake

58 of the

pump

52 is connected by piping 60 to the discharge side of

filter

20, the

pipe

60 entering through

filter

20 at its lower end as shown in FIG. l. The

outlet

62 of

pump

52 is connected by piping 64 to the tank S4 at an

inlet

66 near the bottom of the tank. Two

electrical heater elements

68 and 70 are mounted inside the

tank

54 near its bottom end for heating the cleaning liquid in

tank

54 to a temperature which is sufiiciently high that when the liquid is sprayed from the

nozzles

24 onto the carpet 26 as shown in FIG. 2, it will provide effective cleaning. Where the cleaning liquid is water, it may be heated by

heating elements

68 and 70 to a temperature of about ISO-190 F. The

heating elements

68 and 70 are energized electrically by means of a circuit shown in FIG. 3 which will be described later. The liquid partially fills the tank S4 and is pumped by

pump

52 through

conduit

42 to the

discharge nozzles

24 where it is sprayed onto the carpet 26.

Thermometers

72 and 74 are provided in the piping as a

pressure gauge

78. Other gauges may be provided if needed. A valve is provided at

inlet

66 and may be opened for purposes of draining the

tank

54. A

valve

82 is provided in

conduit

42 for controlling the flow of liquid therein. AS previously mentioned, an on-off control valve is provided on the

handle

38 and is connected in

conduit

42 for purposes of turning the

spray

40 on and off as the

head

22 is manipulated, this on-off valve being omitted from the drawings for lack of space.

In operation, liquid is pumped from the intake portion of

tank

18 through the

filter

20 where soil is removed to the discharge side of

filter

20 and from there through piping 56,

tank

54 and

conduit

42 to the

nozzles

24. Excess liquid and soil is sucked through

tube

27 and

conduit

44 to the

inlet

46 where it enters the

tank

16 and ows into the liquid stored in

tank

16. Thus, th'e liquid is constantly recirculated and only a relatively small portion of the liquid is left in the carpet. This means that the liquid level in the

tank

16 drops relatively slowly so that it is not necessary to refill the

tank

16 as often as would be the case if no recirculation were provided. Sinse soil is returned to the

tank

16 along with the liquid, the apparatus might become clogged if it were not for the filtering action of the

filter

20 which keeps the apparatus clean, and perhaps even more important, prevents soil from flowing through the

discharge flow path

50 and back to the carpet 26. The heat supplied by

heating elements

68 and 70 heads the liquid sufficiently to assure good cleaning action.

It may be noted that it would be possible to provide a makeup water system for supplying makeup water to the

tank

16 automatically to replace water left in the carpet. Such a makeup system is not illustrated in the drawings since it is not believed to be essential.

Tapped into the piping 64 is a feedback conduit 90 having a bypass valve `92 in it for controlling liquid flow therein. The piping 90 enters the

tank

16 at an

inlet

94 which is located just below the top of the normal liquid level in the

tank

16. The

inlet

94 is preferably at an angle relative to the wall of the

tank

16 such that it approaches a tangent relationship with the circumference of the tank. When the pressure in the piping 64 builds up sufiiciently, the

bypass valve

92 opens to allow liquid to be fed back through piping 90 and

inlet

94 into the liquid in

tank

16. As the feedback liquid enters the water in the tank, it exerts force on the water causing it to swirl crcularly about the circumference of the tank, and thus dirt present in the water in the tank tends to concentrate near the wall of the tank so that there is less tendency for large particles of dirt to collect on the

filter

20. This means that it takes longer for the filter to become clogged than if no feedback were provided.

Also tapped into the piping 64 is a

backflush path

100 having a

control valve

102 therein. The

path

100 communicates with

pipe

60. The

valve

102 may be opened and

valve

104 closed when it is desired to backflush the

filter

20. There is a

pipe

106 connected to

valve

82, and

pipe

106 extends down into tank 54 a substantial distance. When liquid is pumped into

tank

54, an air cushion is created at the top of the inside of

tank

54. When

valve

104 is closed and

valve

102 is opened, the pressure of this air cushion causes liquid to be forced backwards through

pipe

102 and piping 60 into the inside of

filter

20 and backward through the

filter

20 so as to fiush contaminants out of the filter material. This rejuvenates the filter for further use. However, it may be noted that the

filter

20 may be replaced rather than rejuvenated after a certain period of filtering, if desired.

A control circuit for energizing the

heating elements

68 and 70 is shown in FIG. 3. Supply leads 110 and 112 are provided, and it may be seen that

heating element

68 is connected across supply leads 110 and 112 through a

thermostatic switch

114. Thus,

heating element

68 is controlled automatically to heat the liquid in the tank S4 to a desired temperature. The

other heating element

70 serves as an auxiliary heater, and is controlled by means of a

switch

116 connected to supply

lead

112 and to

heating element

70 which in turn is connected to supply

lead

110. When

switch

116 is thrown to the left to make contact with

fixed contact

118, the energizing circuit for

heating element

70 is closed. In this condition, both heating elements are operative, and the water in

tank

54 will heat up rapidly. When the water reaches the proper ternperature, switch 116 may be thrown to the right to make contact with

fixed contact

120 which then energizes the

pump motor

122 for

pump

52 and the

motor

124 for

vacuum blower

48.

Motors

122 and 124 are connected in parallel with each other and to lead 126.

FIG. 4 shows a

cleaning machine

200 which is a single tank machine in accordance with another embodiment of the invention. The tank 202 is mounted on a

support base

204 which in turn is mounted on ffoor-engaging

wheels

206 to give the

base

204 mobility, The tank 202 forms a

chamber

208 in which a

filter

210 is retained. The

filter

210 is cylindrical and hollow and closed at both ends.

Filter

210 is mounted in exactly the same manner as described in connection with the

tank

16 of FIG. 1. The outside of

filter

210 is its intake side and the inside of

filter

210 is its discharge side.

Two

heating elements

212 and 214 are mounted in the tank 202, and these heating elements correspond exactly to

heating elements

68 and 70 described in connection with FIGS. 1 and 3 except that they are mounted in the single tank 202 rather than in a

separate tank

54. The circuit for controlling the

heating elements

212 and 214 may be the same as shown in FIG. 3. As previously pointed out, the

filter

210 could be a circular disk type of filter extending transversely across the

chamber

208 above the

heating elements

212 and 214. ln this case, the

water in tank 202 would be heated on the discharge side of

filter

210, whereas in the embodiment actually illustrated in FIG. 4 the water is heated intake side of

filter

210.

The tank 202 is normally filled with liquid to a level just below an

inlet

212. The

inlet

212 is connected with the cleaning

head

22 by a

flexible conduit

44, and it will be assumed for purposes of this description that the

same head

22 is used with the machine of FIG. 4 as has been described previously in connection with the machine of FIG. 1. Similarly, a

vacuum blower

48 of the contrifugal type is mounted on the top of tank 202. It may be noted at this point that the top of tank 202 and also the top of

tank

18 are removable to facilitate filling of the tanks. Thus, the

blowers

48 are removable from the tanks. An advantage of this is that the blower and top can be placed on a separate tank when it is desired to circulate water to such a separate tank rather than to the

main tank

18 or 202.

It will be assumed that the

same conduit

42 is provided for connection from the tank 202 to the

nozzles

24 as has been described previously. However, in FIG. 4 the

conduit

42 is connected through piping 214 and a

pump

216 directly to the tank 202 rather than through a

separate tank

54. The inlet 218 of

pump

216 is connected by piping 220 to the discharge side or inside of the

filter

210. A

pressure gauge

222 and a

thermometer

224 are provided in this piping. The

outlet

226 of

pump

216 is connected by piping 228 through a

valve

230 with the

conduit

42. Piping 232 having a bypass valve 2314 therein is connected from

pipe

228 back to the tank 202 to provide a feedback path which is substantially the same as the feedback path described in connection with FIG. l. A

valve

236 is provided for draining the tank 202. A

thermometer

238 is provided in

piping

228. Referring to FIG. 3, it may be considered that

motor

124 drives the

blower

48 and

motor

122 drives the

pump

216.

In operation, pump 216 is actuated to pump liquid from the intake side of

filter

210 through the filter to the discharge side thereof and out through

piping

220, pump 216, piping 230 and

conduit

42 to the

discharge nozzles

24 of

head

22. The cleaning liquid is sprayed by the

nozzles

24 onto the carpet 26. Excess liquid is sucked into

tube

27 and flows through

conduit

44 to the space above the liquid inside tank 202 because of suction produced by the

vacuum blower

48 in this space. Soil fiows with this returning liquid. The soil and recycled liquid mix with the liquid in tank 202, and the soil is filtered out by

filter

210. The recirculating liquid is heated by

heating elements

212 and 214 to a temperature sufficient to assure good cleaning action.

When sufficient pressure builds up in piping 228, part of the liquid pumped by

pump

216 is fed back through piping 232 and

valve

234 to tank 202. This liquid enters at

inlet

250 which is almost tangential with respect to the circumference of tank 202, and the ow of liquid entering the tank at this angle causes the stored liquid in the tank to swirl so that heavied particles of dirt in the liquid tend to concentrate near the larger particles of dirt from clogging the

filter

210 to prolong the filtering cycle. When the

filter

210 does become clogged, it may be cleaned or replaced.

Thus, the invention provides a cleaning machine which provides efiicient cleaning by means of a combination of recirculation, filtering and heating.

Having thus described our invention, we claim:

1. A machine for cleaning carpets or the like comprising support means, means afiixed to said support means forming a chamber for containing cleaning liquid, a filter for liquids retained in said chamber and having an intake side and a discharge side, said filter being mounted relative to said chamber to filter liquid passing from said intake side to said discharge side thereof in said chamber, a cleaning head having a discharge fiow path for directing liquid forcibly onto a carpet or the like and a return ow path for withdrawing excess liquid and soil from a carpet or the like, a discharge liquid fiow circuit communicating a portion of said chamber on the discharge side of said filter with said discharge fiow path of said head, said discharge liquid flow circuit including a tank separate from said chamber, a return liquid fiow circuit communicating said return fiow path of said head with a portion of said chamber on the intake side of said filter, heater means in said tank for heating cleaning liquid therein to an elevated temperature sufficiently high to assure that when said cleaning liquid is discharged from said head it is effective to clean a carpet or the like, pumping means in said discharge flow circuit for causing liquid to fiow from the intake side of said filter through said filter and out from the discharge side thereof through said discharge flow circuit and said discharge flow path of said head onto a carpet or the like with sufficient force to facilitate cleaning, a back fiush fiow path having a valve therein and connected across said pumping means in bypassing relation therewith for feeding the liquid from said tank back to said filter for backfiushing, means associated with the portion of said chamber on the intake side of said filter for sucking excess liquid and soil from a carpet or the like into said return flow path of said head and for causing the same to fiow through said return fiow circuit into said chamber on the intake side of said filter for flow through said filter with said filter serving to remove contaminants from said liquid, said last-named means including blower means, means to operate said pumping means and means to operate said blower means.

2. A machine for cleaning carpets or the like, comprising support means, means affixed to said support means forming a chamber for containing a cleaning liquid, said chamber comprising a hollow tank rising vertically above said support means and having a mouth at the top thereof, and a generally horizontal lid adapted to be removably mounted on said mouth at the top of said tank, a filter for liquids [retained in] communicating with said chamber and having an intake side and a discharge side, said filter [being located adjacent the bottom of said chamber] serving to filter liquid passing from said intake side to said discharge side thereof, [said filter terminating substantially above the bottom of said chamber and being removable from said chamber for cleaning or exchange purposes by removing said lid from said chamber to provide access to said filter, said chamber having a free and unobstructed region therein below said lid and said mouth and above said filter to allow easy access to said filter,] a cleaning head having a discharge flow path for directing liquid forcibly onto a carpet or the like and a return flow path for withdrawing excess liquid and soil from a carpet or the like, a discharge liquid fiow circuit connecting a portion of said chamber [on the discharge side of said filter] with said discharge fiow path of said head, said filter being in said discharge flow circuit, a return liquid flow circuit [connecting said return fiow path of said head with said unobstructed region of said chamber below said lid], electrical heater means in [the liquid path] said tank for heating the cleaning liquid in said tank to an elevated temperature sufficiently high to assure that when said cleaning liquid is discharged from said head it is effective to clean a carpet or the like, electrical control circuit means for controlling said heater means, said heater means including first and second heater elements, and said control circuit means including a first switch connected to operate said first heater element as needed to maintain a regulated temperature in said liquid and a second switch connected to turn said second heater element on and off separately, pumping means in said discharge flow circuit for causing liquid to fiow [from the intake side of said filter] through said filter and [out from the discharge side thereof] through said discharge flow circuit and said discharge flow path of said head onto a carpet or the like with sufficient force to facilitate cleaning, centrifugal blower means mounted above and on top of the lid [of said chamber above the mouth at the top of said tank], said centrifugal blower means communicating with said unobstructed region below said lid in said tank for blowing air from said tank so as to suck excess liquid and soil from a carpet or the like into said return fiow path of said head and for causing the same to flow through said return ow circuit into said chamber [at the region above said filter] for subsequent fiow through said filter with said filter serving to remove contaminants from said liquid, said centrifugal blower means and said lid being removable together from said chamber without detachment of any portion thereof from said blower means [(1)] to allow filling of said chamber, [(2)] to provide access to said filter,] and [(3)] to allow said lid and blower means to be placed on said mouth without interference below said lid and removed easily and placed together on a separate tank when it is desired to recirculate dirty liquid to such separate tank rather than to said chamber.

3. A machine for cleaning carpets or the like, comprising support means, means affixed to said support means forming a chamber for containing a cleaning liquid, said chamber comprising a hollow tank rising vertically above said support means and having a mouth at the top thereof, and a generally horizontal lid removably mounted on said mouth at the top of said tank, a filter for liquids retained in said chamber and having an intake side and a discharge side, said filter being located adjacent the bottom of said chamber to filter liquid passing from said intake side to said discharge side thereof, said filter terminating substantially above the bottom of said chamber and being removable from said chamber for cleaning or exchange purposes by removing said lid from said chamber to provide access to said filter, said chamber having a free and unobstructed region therein below said lid and said mouth and above said filter to allow easy access to said filter, a cleaning head having a discharge fiow path for directing liquid forcibly onto a carpet or the like and a return fiow path for withdrawing excess liquid and soil from a carpet or the like, a discharge liquid flow circuit connecting a portion of said chamber on the discharge side of said filter with said discharge fiow path of said head, a return liquid fiow circuit connecting said return fiow path of said head with said unobstructed region of said chamber below said lid, electrical heater means in the liquid path for heating the cleaning liquid to an elevated temperature sufficiently high to assure that when said cleaning liquid is discharged from said head it is effective to clean a carpet or the like, electrical control circuit means for controlling said heater means, pumping means in said discharge flow circuit for causing liquid to flow from the intake side of said filter through said filter and out from the discharge side thereof through said discharge ow circuit and said discharge fiow path of said head onto a carpet or the like with sufficient force to facilitate cleaning, centrifugal blower means mounted above and on top of the lid of said chamber above the mouth at the top of said tank, said centrifugal blower means communicating with said unobstructed region below said lid in said tank for blowing air from said tank so as to suck excess liquid and soil from a carpet or the like into said return fiow path of said `head and for causing the same to fiow through said return flow circuit into said chamber at the region above said filter for subsequent flow through said filter with said filter serving to remove contaminants from said liquid, said centrifugal blower means and said lid being removable together from said chamber without detachment of any portion thereof from said blower means (1) to allow filling of said chamber, (2) to provide access to said filter, and (3) to allow said lid and blower means to be placed on said mouth without interference below said lid and removed easily and placed together on a separate tank when it is desired to recirculate dirty liquid to such separate tank rather than t0 said chamber, said discharge liquid ow circuit including a further tank separate from said chamber, Said heater means being located in said latter separate tank, and said machine including a back Hush ow path having a valve therein and connected across said pumping means in bypass relation therewith for feeding liquid from said latter tank back to said lter for back flushing.

References Cited The following references, cited by the Examiner, are of record in the patented file 0f this patent or the original patent.

UNITED STgES PATENTS 2,292,435 S/1942 Crites 15-321 3,43l,582 3/1969 Grave l5-321 2,909,800 lil/1959 Grindle et al. 15-321 FOREIGN PATENTS 584,806 10/1959 Canada 15-321 1,111,899 5/1968 Great Brit-nin 15-320 EDWARD L. ROBERTS, Primary Examiner C. K. MOORE, Assistant Examiner