US3861865A

US3861865A - Drying system

Info

Publication number: US3861865A
Application number: US443484A
Authority: US
Inventors: Frederick W Grantham
Original assignee: Frederick W Grantham
Current assignee: ROSCO MACHINERY Co Inc
Priority date: 1974-02-19
Filing date: 1974-02-19
Publication date: 1975-01-21
Anticipated expiration: 1992-01-21

Abstract

An improved laundry dryer-conditioner is provided which utilizes air moving at a relatively high velocity and in a significant volume to replace the expensive fragile, heavy and short-lived refactory and other heat resistive materials, which are conventionally found in the combustion and air-heating chambers of such apparatus.

Description

United States Patent 1191 Grantham 1 Jan. 21, 1975 1 DRYING SYSTEM 2,643,463 6/1953 Grantham 34/133 2,827,276 3/1958 Racheter.... 34/133 [76] Invent Frederck Grantham 12055 3,624,919 12/1971 M11161 34/133 Goshe" Ave-1 L05 Angeles Callfi 3,659,352 5/1972 Cook 34/191 90066 22 l 19 974 Primary EJtaminer-Kenneth W. Sprague Assistant Examiner.lames C. Yeung [2]] Appl' N05 443,484 Attorney, Agent, or Firm-Henry M. Bissell [52] U.S. Cl 432/105, 432/107, 34/133, ABSTRACT 34/139 An improved laundry dryer-conditioner is provided [51] Int. Cl. F27b 7/02 which utilizes air moving at a relatively high velocity [58] Field of Search 34/131, 133, 134, 139, and in a significant volume to replace the expensive 34/130, 138; 432/105, 107, 103 fragile, heavy and short-lived refactory and other heat resistive materials, which are conventionally found in [56] References Cited the combustion and air-heating chambers of such ap UNITED STATES PATENTS p 2,498,172 2/1950 Mintner 432/107 11 Claims, 5 Drawing Figures DRYING SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the field of laundry and other article-drying equipment and, more specifically, to dryer-conditioners used in the commercial laundering industry.

2. Description of the Prior Art An overall view of the prior art in industrial laundry dryer-conditioners, often referred to in the industry as merely dryers," can be had by referring to my earlierissued US. Pat. Nos. 2,604,313, 2,643,463 and 3,443,323. The dryers described in those patents and industrial dryers in general require large volumes of air having a temperature, in the tumbler, in the range of 300 to 350 F., in addition to providing the tumbling action to the laundry, to achieve rapid, but safe, drying.

These elevated temperatures are achieved by the burning of fuel such as natural gas, propane, butane or oil in a combustion chamber from which hot air is caused to flow into the dryer housing by appropriate air pumps or blowers. The fuel is mixed with appropriate proportions of air to give clean burning and is introduced into the combustion chamber under pressure at one end of the chamber. At the opposite end of the chamber it is conventional to have a slab of refractory material, which may weigh as much as 200 pounds and closes off the end of the chamber. Such material deteriorates with operation of the dryer and after several years must be replaced at considerable expense and loss of operating time. The weight of the slab adds to shipping costs for the dryer. In addition the slab has its own inherent initial cost. Further, it may crack during shipment, being somewhat fragile in nature.

In addition to the problems associated with the end closure of the combustion chamber, its outer walls become very hot during operation of the unit because internal temperatures of l,700 F. may occur in the chamber. As a result it has been conventional to incur the additional cost and weight associated with wrapping the chamber with multiple layers of asbestos.

SUMMARY OF THE INVENTION Stated succinctly, I have eliminated both the refractory end closure and the asbestos covering of the combustion chamber in a laundry dryer-conditioner by the use of high-volume, high-velocity air flowing over and through the proper regions in and about the combustion chamber. I have, in essence, created at the end of the combustion chamber remote from the fuel burner an air barrier which prevents the intensely heated air and other gases generated by the fuel burner from exiting at the end of the chamber. in the same manner as the refactory endpiece prevents such exiting in the conventional combustion chamber for a laundry dryer.

To eliminate the need for an asbestos wrapping of the combustion chamber I have provided a double-walled combustion chamber with cooling air pumped through the space between the double walls by the same air pump or blower which provides the drying air for the laundry and also provides the air barrier at the end of the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWINGS Other aspects of the invention, along with other objects and advantages thereof, will become apparent from a reading of the detailed description which appears hereinafter, in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view, in elevation, of a dryerconditioner system incorporating my invention;

FIG. 2 is a side view, in elevation, of a portion of the apparatus of FIG. 1;

FIG. 3 is a sideview, in elevation, of the blower and combustion chamber of FIG. 1 with one combustion chamber wall partially cut away and the air-fuel mixing and introduction means simplified;

FIG. 4 is a sectional view of the combustion chamber of FIG. 3, taken along the line 4-4 of FIG. 3; and

FIG. 5 is an elevational view of the opposite side of the blower or air pump shown in FIG. 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 1, dryer-conditioner system includes housing 11; basket 12 rotatably supported within housing 11; cover 13, which is shown in its position removed from its placement during actual operation of the system; combustion chamber 14; control center 15 which provides the controls for operating combustion chamber 14 and positioning housing 11 and cover 13; and base 16 which supports housing 11 in a tiltable fashion.

Housing 11 is shown in position for the loading of laundry into basket 12. In this loading position housing 11 is tilted backwardly by mechanical means, not shown, the axis of rotation being about journal 17 and its opposite member on the opposite end of housing ll, not shown. In this position for loading, cover 13 is moved into a position remote from from opening 18, which front opening is surrounded by gasket 19 for sealing of this opening during the operation of drying system 10. Cover positioner 20 may be a pneumatic or hydraulic actuator which cooperates, through chain member 21, with teeth 22 on gear member 23 to which arm 24 is secured. When positioner 20 receives a signal from control center 15 it pulls downwardly on chain 21 causing gear member 23 to rotate and raising cover 13 away from its position in cooperation with gasket 19 surrounding loading opening 18 in housing 11. A similar pneumatic or hydraulic actuator may be provided on the opposite side of housing 11 shown in FIG. 2. In this loading position hot air exit aperture 25 in combustion chamber 14 is exposed. Of course, at this time the circuits of control center 15 have extinguished the main flame in combustion chamber 14 leaving only the pilot light burning in that chamber. The internal details of combustion chamber 14 are set forth more fully and will be described more fully in connection with FIG. 3. Similarly, the function of exhaust stack will become more apparent in connection with the discussion of.

FIG. 3.

In FIG. 2, housing 11 is shown in an upright position, ready for operation of the dryer. It is to be noted that when housing 11 is in an upright position, cover 13 has .been positioned in cooperation with gasket 19 surrounding loading opening 18 in housing 11. This is accomplished by releasing the tension on chain 21 and its counterpart chain 27 through control of

positioners

20 and 28, respectively. As can be seen from FIG. 2, housing 11 has hot air inlet aperture 29 which is positioned in alignment with aperture 25 in combustion chamber 14 when housing 11 is in its upright position for operation of the drying system. It should be noted, however, that

apertures

25 and 29 are not joined by a positive seal during operation of the system. A space is provided between

apertures

25 and 29 so that the air which is emerging from aperture 25 (and may have temperatures approaching 1,700 F. is mixed with relatively cool air from the environment surrounding the system. As a result, the air entering the basket 12 has a temperature approximating 500 F. The need for tempering the air exiting from the combustion chamber is recognized and discussed in my two US. Pat. Nos. 2,604,3 l3 and 2,643,463.

Aperture 30 in housing 1 l is provided for channeling air out of housing 11 and is positioned so that when housing 11 is oriented for operation of the system, aperture 30 is aligned with the return inlet of the air pump or blower in the system, such air pump or blower being described more fully in connection with FIGS. 3 and 5.

In FIG. 3, combustion chamber 14 has an outer wall 31 and an inner wall 32 separated therefrom by spacers 33 shown more clearly in FIGS. 1 and 4. Air may enter freely from either end of combustion chamber 14 and pass through the space between outer wall 31 and inner wall 32 of combustion chamber 14. Inner wall 32 has aperture 34 therein which communicates with hot air exit aperture 25 in outer wall 31 and with the spaces between inner wall 32 and outer wall 31. Aperture 34 may be of the same size as aperture 25 in outer wall 31. The fuel introduction and burning system shown in FIG. 3 is a simplified version of that indicated in FIG. 1 and comprises a fuel-gas mixing chamber 35 which receives fuel through pipe 36 and air, usually under pressure as developed by blower 37 in FIG. 1. The chamber may also have an automatic flap valve which adjusts the air input to the mixture as the fuel flow changes. A pilot flame 47 is provided to light the airfuel mixture issuing from jet 48 when the system is operating in the dry mode. All of the conventional safety features, such as automatic shut off of the fuel valve if the pilot flame is inadvertently extinguished and interlocking features which automatically shut down the system if any of the normal conditions for operation of system are departed from, are provided but need not be explained here since they are all well known in the art.

Blower or air pump 37 has the mouth of its outlet duct 38 positioned proximate to the lower side of end 39 in combustion chamber 14, as shown in FIG. 3. Exhaust stack 40 is also positioned adjacent end 39 of combustion chamber 14 but is spaced from outlet duct 38 by approximately the diameter of combustion chamber 14, as shown.

In the sectional view of FIG. 4, the combustion chamber 14 is shown with outer wall 31, inner wall 32 spaced from outer wall 31 by spacers 33, and the rear disk or end wall portion 42 which is a continuation of inner wall 32. Disk portion 42 has aperture 41 therein. Because of the temperatures achieved and the corrosion which would otherwise occur, inner wall 32 and disk portion 42 may be formed of corrosion resistant material such as stainless steel, particularly if the fuel being burned is oil.

FIG. shows the reverse side of the blower 37 from that shown in FIG. 3. It is noted that an air inlet 43 is provided and that this inlet has a size and a position so as to assure alignment and communication between the inlet 43 and aperture 30 in housing 11 when housing 11 is oriented for a drying operation. A gasket 44 may be provided around the inlet 43 to assure a tight seal between inlet 43 and exhaust aperture 30 during operation of the system. Air pump 37 may be of the centrifugal variety in which case it will have blades 45 which propel the air outwardly through outlet duct 38.

For operation of the system the appropriate button on control center 15 is pressed to bring housing 11 to an upright position and at the same time to bring cover 13 into firm contact with gasket 19 surrounding aperture 18 in housing 11. With this positioning of housing 11, hot air aperture 25 in combustion chamber 14 is aligned with but spaced from aperture 29 in housing 11 to permit the mixture of hot air from the combustion chamber 14 with room ambient air adjacent the

apertures

25, 29 for passage into housing 11 at the proper temperature. correspondingly, air inlet aperture 43 and blower 37 are positioned so that gasket 44 is coincident with the periphery of aperture 30 in housing 11 to permit the pumping of air out of housing 11. With all interlocks and safety mechanisms closed, pilot flame 47 is used to ignite the fuel-air mixture emanating from jet 48 and a high temperature flame of considerable magnitude resuls. At the same time, blower 37 commences operation extracting air from housing 11, producing a lowered pressure therein and causing an inflow of air at aperture 29 in housing 11, part of which is hot air from the combustion chamber 14. This hot air passes through aperture 34 in inner wall 32 and through aperture 25 in outer wall 31 into the upper portion of housing 11 from whence it passes through basket 12 and the laundry or other articles therein for exiting at aperture 30 in the lower portion of housing 11 to be re-pumped by blower 37.

Not only does air from the combustion chamber 14 pass through

apertures

34 and 25 into housing 11 through aperture 29 but, because of the differential pressure gradient across

apertures

29, 25 and 34 as a result of the action of blower 37, air is drawn through the space separating walls 3l,and 32 of combustion chamber 14. Part of that air will be at room ambient temperature, namely that part entering from front end 46 of combustion chamber 14. Air also enters the space between the inner and outer walls from rear end 39 of combustion chamber 14 and flows between the inner and outer walls of the combustion chamber 14. This air at room ambient temperature or at temperatures considerably below the internal temperature of combustion chamber 14 will cause cooling of the inner wall 32 of combustion chamber 14 thus protecting the inner wall against extreme temperatures while insulating the outer wall 31 therefrom. As a result, the need for wrapping combustion chamber 14 in asbestos, as is presently being done by dryer-conditioners not incorporating my invention, will be obviated. The reduced pressure within the inner walls of combustion chamber 14 as a result of the communication of

apertures

34 and 25 with aperture 29 in housing 11 not only results in an overflow of air from the space between the inner and outer walls of combustion chamber 14 but also causes an inward diversion and recirculation of part of the air stream exiting from outlet duct 38 associated with blower 37. The blast of air entering through aperture 41 in disk 42 of rear end portion 39 in combustion chamber 14 develops an effective air barrier which prevents the flame and hot gases produced at jet 48 from impinging upon disk 42 at end 39 of combustion chamber 14. The air emanating from outletduct 38 is substantially reduced in temperature from that existing within combustion chamber 14 by reason of the heat absorption experienced in evaporating the water in the laundry within basket 12 as that basket rotates within housing 11. A portion of the exhaust air is drawn into combustion chamber 14 through aperture 41 and into the space between inner and

outer walls

31 and 32, flowing out through

apertures

34, 25 to enter housing 11 through aperture 29, thus tending to provide a more efficient use of fuel for the drying process by partial recirculation. Air from outletduct 38 which does not enter combustion chamber 14 either through aperture 41 or through the space between the inner and outer walls passes out of stack 40 through an appropriate lint trap, not shown.

Suitable temperature-sensing devices may be provided within housing 11 to prevent overheating of the materials being dried or laundered. Temperature sensors may be placed within housing 11 to control the flow of fuel into jet 48 and thus control the temperature of the drying air entering housing 11 through aperture 29. As was indicated earlier, aperture 25 in outer wall 31 and aperture 29 in the outer wall of housing 11 may be spaced from each other. This will allow, as a result of the lessened atmospheric pressure at aperture 29 when the system is in operation, the inflow of room air through the space between outer wall 31 of combustion chamber 14 and the opposing wall of housing 11.

Actual field experience with a system according to my invention has shown that, by reason of the nature of operation of the system according to my invention, the outer wall 31 of combustion chamber 14 need not be covered with asbestos as combustion chambers must be if they do not incorporate my invention, and the disadvantages previously experienced with refractory materials palced in the end of the combustion chamber in previous dryer-conditioner systems have been eliminated.

While a particular dryer-conditioner system has been shown and described herein for the purpose of illustrating the manner in which my invention may be used to an advantage, it will be appreciated that my invention is not limited thereto. Accordingly, any and all modifications, variations, or equivalent arrangements which may occur to those skilled in the art should be considered to be within the scope of my invention.

What is claimed is:

1. Apparatus for drying articles by the flow of preheated air comprising:

a housing having an air inlet opening and an air outlet opening;

means within the housing for supporting the articles to be dried;

air conduit means mounted externally of the housing having portions in alignment with the inlet and outlet openings respectively;

a combustion chamber having a flame source end, an opposed apertured end, and a discrete side opening spaced from said apertured end toward said flame source end and communicating with the conduit means aligned with the housing inlet opening; and

blower means coupled in series with the conduit means for directing air from the housing outlet opening to the vicinity of the apertured end of the combustion chamber.

2. Apparatus in accordance with claim 1 wherein the conduit means aligned with the inlet opening of the housing is spaced by a predetermined distance from said opening to permit ambient air to be drawn into said opening together with preheated air from the combustion chamber.

3. Apparatus in accordance with claim 2 wherein the combustion chamber, blower means and conduit means are arranged to draw a portion of the air exiting the housing outlet opening into the combustion chamber through the apertured end for further heating and recirculation through the housing.

4. Apparatus in accordance with claim 3 wherein the combustion chamber is configured to form an air barrier for the flame from the flame source end by means of the air flowing into the combustion chamber from the apertured end.

5. Apparatus in accordance with claim 1 wherein the combustion chamber comprises spaced-apart inner and outer walls with support means extending between the two, the walls and support means defining an inter wall space open at both ends for the flow of air therethrough.

6. Apparatus in accordance with claim 5 wherein each of said inner and outer walls includes means delining respective aligned side openings therein communicating with said conduit means in alignment with the inlet opening of the housing.

7. Apparatus in accordance with claim 6 wherein the conduit means aligned with the outlet opening of the housing further includes sealing means for establishing an abutting relationship between said conduit means and the housing at said outlet opening.

8. Apparatus in accordance with claim 3 wherein the conduit means further includes an exhaust stack portion and a conduit portion for directing air from the blower means to the exhaust stack portion, both the outlet of said conduit portion and the inlet of said exhaust stack portion being positioned adjacent the apertured end of the combustion chamber but spaced apart from each other.

9. Apparatus in accordance with claim 8 wherein the spacing between the conduit and exhaust stack portions is open to admit ambient air as drawn by the blower means through the apertured end of the combustion chamber.

10. Apparatus in accordance with claim 5 wherein the combustion chamber comprises a generally cylindrical inner wall having attached, generally closed end walls, the flame source end wall having a flame source mounted therein and extending therethrough, the opposed apertured end wall having a central aperture therein approximating one-third the diameter of the cylindrical inner wall, and a generally cylindrical outer wall open at both ends.

11. Apparatus in accordance with claim 1 further including control means for coordinating the actuation of said flame source and said blower means.

Claims

1. Apparatus for drying articles by the flow of pre-heated air comprising: a housing having an air inlet opening and an air outlet opening; means within the housing for supporting the articles to be dried; air conduit means mounted externally of the housing having portions in alignment with the inlet and outlet openings respectively; a combustion chamber having a flame source end, an opposed apertured end, and a discrete side opening spaced from said apertured end toward said flame source end and communicating with the conduit means aligned with the housing inlet opening; and blower means coupled in series with the conduit means for directing air from the housing outlet opening to the vicinity of the apertured end of the combustion chamber.

6. Apparatus in accordance with claim 5 wherein each of said inner and outer walls includes means defining respective aligned side openings therein communicating with said conduit means in alignment with the inlet opening of the housing.