US2363467A - Apparatus for drying - Google Patents

Description

Noy. 21, 1944. w. S;I'RQBRIDGE- APPARATUS FOR DRYING Filed Jan. 13, 1942 8 Sheets-Shegt l INVENTOR Wz'lZim/z \btrobr idye A1 ATTORNEY? N v-21, wsmBRml-z 2,363,4 7

APPARATUS FOR DRYING Filed Jan. 13, 1942 8 Sheets-Sheet 2 INVENTOR Wilda/n b' frobriaye Nov.'2l, 1944. WATROB LDGE 2,363,467

7 APPARATUS FOR DRYING Filed Jan. 13, 1942 Y 8 Sheets-Sheet 3 4 INVENTOR -,Wlliam s il'obridje ATTORNEYS Nov. 21, 1944.

W. STROBRIDGE I APPARATUS FOR DRYING Filed Jan. 13. 1942 S SheetS-She'et 4 e 0 1 m Y mh .m

Nov; 21, 1944. 'w STROBRIDGE v 2,363,467

' APPARATUS FOR DRYING Filed Jan. 15, 1942 sheetsshee't lNVENTOR William 5' il'obrp'd je r. $512M v/o gwmj ATTORNEY Nov. 21, 1944. w. STROBRIDGE 2,363,467

APPARATUS FOR DRYING Filed Jan. 13, 1942 8 Sheets-Sheet 6 INVENTOR B illiant fitrobrz'a 6 Nov. 21,1944. $TR0'B R|DGE 2,363,467

APPARATUS FOR DRYING Filed Jan. '13, 1942 8 Sheets-Sheet 7 INVENTOR William fiil'ofu'id e ATTORNEYS W. STROBRIDGE APPARATUS FQR DRYING Nov. 21, 1944.

Filed Jan. 13, 1942 8 Sheet s-Sheet 8 injury to the Patented Nov. 21, 1944 PATENT OFFICE 2,363,467 APPARATUS FOR DRYING William Strobridge, Syracuse, N. Y., assignor to United States Hofiman Machinery Corporation,

New York, N. Y., a corporation of Delaware Application January 13, 1942, Serial No. 426,570

. Claims. This invention relates to apparatus employed in dry cleaning, and more particularly to apparatus for drying materials which have previously been treated with an inflammable cleaning solvent. Such apparatus forms of U. S. Patent 2,203,422 fssued'June 4, 1940, and U. S. Patent 2,217,153 issued October 8, 1940. Patent 2,203,422 discloses a drying tumbler in which the materials to be dried are first subjected to the flow of air maintained at a safe maximum temperature relative to the flash-point of the solvent used, for a predetermined interval rf time for the removal of the greater part of the solvent, then subjected to a flow of air at a temperature considerably point for another predetermined interval of time, and finally subjected again to a flow of air at a safe temperature relative to the flash-point, to cool and complete deodorization of the materials and to down to a point where the cycle of operation might immediately be repeated with safety. In that apparatus air is drawn then through a rotating clothes containing cylinder by means of an electrically driven fair which discharges the solvent laden air to the atmosphere outside the tumbler. 'Toinsure safe operation, certain relays and .interlocks areprovided to make it imposs'ble td "start rotation of the tumbler drum unless the in operaiton by connecting the fan motor to acurrent source, and provision is made for automatically spraying the interior of the tumbler with steam and/or sounding a steam whistle in the event of current failure to the fan during op- --eration of -the tumbler.

It is an object of the present invention-to provide improved apparatus of the forth.

. To this end the electrically driven fan has 10 v been replaced by a fan driven by a steam turbine so that in the event of current failure there would still be a circulation of air through the tumbler, and any tendency to generate a flammable vapor-air mixture would be obviated. This avoid the necessity of sounding a whistle orinjecting steam into the tumbler to prevent explosion'or goods within the tumbler drum.

In order to make emc'ient useof'the exhaust steam from the turbine, this is utilized in a primary heater which remains in operation throughout the entire drying cycle. This exhaust steam is the sole source of heat during the low heat and cooling periods of operation of the tumbler,

and is controlled to maintain the air at the max 5 heater i1. Each the subject matter 5 higher than the flash- 15 bring the temperature within the dryer go through a heater.

fan has first been t 30 apparatus and character set imum temperature for those periods. The air issuing from the primary-heater passes through a secondary heater which, during the high heat period of the cycle, is supplied with live steam to heat the air supply the flash-point of the solvent.

Other objects will be in part obvious and in' part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements,

and-arrangements of parts as will be exemplified in the structureto be hereinafter described and the scope of the application of which will be indicated in the following claims.

In 1 the accompanying drawings in which s shown" one of the various possible embodiments of my invention- Fig. 1 is a front elevation of a tumbler emb dying. features of the present invention;

Fig.2 is a right side elevation thereof;

Fig. 3 is a left side elevation thereof;

Fig. 4 is arear elevation thereof;

Fig. 5. is a cross-section on line Fig. 6 is a top plan view of the rear portion of the operating and control devices;

top andright and rear sidesof thetumbler;

Fig.-f8 is a wiring diagram devices shown figures. 7. I

Simflar reference characters refer to'similar parts-throughout the various views of the drawings. I

Description of apparatus for a general conception of the preferred'form of apparat There is disclosed a tumbler coniprising'a The drum H is surrounded by an internal cylin- -drical shell 9'2 which encloses the drum for approximately three-quarters of the periphery thereof, the hinged outer shell door It at the front of the tumbler housing completing the enclosure. To the rear of the drum chamber near I the top of the casing l0 there is provided a-coil box It extending rearwardiy through and beyond the rear plate of the casing and connecting with the atmosphere by means of an opening l5.

' The heater 7 Coil box M contains two heater units com? prising a primary heater l6 and a secondary of these heaters preferably is to the desired point above 5--5-of Fig, 4;

the tumbler showing. the location of certain of;

pertaining to the ezv e Reference to Figs. '1 to s inclusive may be had' titer shell or casing l0 having rotatably mounted therein a forami'nous drumil.

. the inlet of the of the fin type wherein the heat from the steam heating coils is radiated by suitable fins which.

surround the coils and provide a plurality of narrow passages for the flow of air, as indicated at l8 in Fig. 4. The primary and secondary heaters I 6 and I! are heated respectively by steam coils I9 and 20. The heater units are slightly spaced apart, as indicated at 2! in Fig. 5, to provide a temperature measuring chamber, the purpose of which will be explained hereinafter.

Air from the secondary heater i1 is led to the.

top of the tumbler and admitted to the drum ll through an opening 22 in the inner shell I2. The air outlet from the drum chamber is through an opening 23 at the bottom of the shell l2, opposite the opening 22. The air thus passes into the lower part of the tumbler casing beneath the drum chamber, where there is located an exhauster. fan 24 having an air inlet 25 and outlet 21, the latter projecting through the rear wall of the casing. The fan is driven, in the present.

be referred to in connection with the wiring dia-.

gram and the description of the operation of the tumbler.

Steam piping The steam piping to the, coils l8 and may best be understood by reference to. Fig. 7. The

steam line dropping down from abovepasses through a manually operated main shut-off valve 3| and then on below to a T 32. Below the T this main line goes to the upturned opening of a T 33, and then continues down from the said T to the inlet 34 of the steam turbine 28. From the outlet 35 of the turbine an exhaust steam line connects with a 1- n and then discharges through a. suitable back pressure valve 31 to the atmosphere, or, if desired, to the heating system of the building in which the tumbler is located. The side outlet of the T 33 is connected to a hand operated valve which connects with a steam spray pipe 4| located inwardly of the secondary heater I! in the air passage leading to the tumbler drum.

From the T 32 a live steam line connects through the lever operated valve 38 directly with secondary heater coil 20. From the T 38 in the turbine exhaust line. a low pressure steam line runs through the thermostatically operated valve 43 to the inlet of coil IS. The thermostatic valve 43 is controlled in its operation by a bulb 44 located between the primary and secondary heaters in the chamber 2 l.

The outlet pipe 46 of the high pressure coil 20 passes through a swing check valve 41 and a high pressure steam trap 48 to any suitable return pipeof the steam heating system. A by-pass in this line contains a suitable thermostatic air venting valve 49. The outlet pipe 46' of the low pressure coil i9 is similarly equipped with a w pressure steam tra swing check valve 41, a and an air venting v ve 49'.

Steam valve 38 in the live steam line to the secondary heater coil 20 is operated automatithe primary heater to the bulb 44. Thus the operation of the valve 43 is controlled by the temperature of the air in the temperature measuring chamber 2| after the air has passed through the primary heater but before the temperature of the air has been influenced by the high pressure secondary heater.

Cylinder drive The tumbler drum shaft II is joumaled in bearings 5| mounted on brackets 52 secured to the sidexplates of the tumbler housing. Upon the shaft II is mounted a spur gear 53 driven by a pinion 54 mounted upon a jack shaft 55- 5' forming part of a pulley and belt shifting header assembly, as best seen in Figs. 1, 3 and 4, in which the jack shaft 55 is shown to be rotatably mounted in a pair of bearings 56, 51 carried by a header bracket or arm 58. This bracket is bolted to the sideof the tumbler housing. The jack shaft 55 carries a tight pulley 59 and a pair of loose pulleys 60, 6|. Also loosely mounted upon the shaft 55 is a header worm 82 which has a pinand-slot connection, not shown, with the hub of the loose pulley 6| so as to be driven thereby.

Mounted upon the header bracket 58 in c0 axial relation to the shaft 55 is a header arm assembly comprising the support 63, to which is pivotally connected the belt shifter fork 64. The header arm assembly includes a worm gear 61- on support 83 meshing with the worm 62, and a reciprocating slide shaft 88 slidably and rotatably mounted at the upper end of the support 83 in a block 89. Projecting from the block 69 para guide rod 18. A weighted pin or header-fall ll secured to and extending 68 shifts with j allel to the shaft 68 is at right angles to the slide shaft the slide shaft about its axis so that the pin H may engage the upper end of the shifter fork 64 when the pin H is swung in one direction to a orizontal position and, sliding along the upper ace of the shifter fork, eventually settle in the notch 12 formed in the upper end of the shifter fork. When swung in the opposite direction to a horizontal positio the pin H will be free of the shifter fork 84 but will engage one or the other of the beveled surfaces 13 on the block 69 and ride down to a neutral position.

Mounted loosely upon the slide shaft 68 in a position between the block 69 and the tumbler housing is s held against endwise movement upon the slide shaft in any suitable manner.. The sleeve carries a forked arm 16 cooperating with the guide 2 provided with belt guide blocks I8 and 19, each equipped with a belt guide are so disposed that when the shifter pin 1| occupies its center or neutral position, the two drive belts 8|, 82 will be positioned upon the loose pulleys so that under these conditions no power will be transmitted to the tumbler drum. It will be noted that the belt 8| crossed whereby the shifting of one shifter sleeve I4. This sleeve is 80. The belt guides the belt 82 is direct and belt of! and the other belt on to the tight pulley will effect a reversal ofthe rotation of the tumbler drum. It will be understood that. belts 8| and 82 connect with a suitable line shaft, not shown, and are of a. width to enable them to drive the tight pulley without disengaging their respective loose pulleys.

The operation of the header .assembly will now be briefly described, It will be noted that since the worm 62 is driven by the loose pulley 6|, it will always rotate in the same direction irrespective of the location of the belts with respect to the tight pulley. Thus, also, the worm wheel 61 will rotate constantly in one direction. This wheel drives a crank pin 83 slidable up and down shift the drive belts and reverse operation of the tumbler drum. For a fuller description of this header construction, referencemay be made to the above mentioned Patent No. 2,203,422.

Mechanically controlled mechanism Referring again to the drawings, mechanical means for setting the tumbler in operation to begin the drying cycle will now be described.

' bracket I85 which is secured to the fixed bracket by means of bolts which pass through arcuate slots in the fixed bracket whereby the adjust- In the position of the parts shown in Fig. 3, the

condition of the apparatus is that which would obtain after 'a batch of material has been placed in the drum and the shell door closed. Under these conditions the'shell door cannot be reopened or the header-fall brought into engagement with the shifter fork to start rotation of the drum until after the exhauster fan has been started, to make certain that there is an active flow of air through the tumbler. It may occur, at the start of a day's work, that the door will be closed and locked in the position shown in Fig. 3, when, as will be shown hereinafter, it will be necessary first to set in operation the steam turbine driven fan before it is possible toopen the shell door for the loading of the drum. But if the door should be 'open prior to starting the fan, the drum may be loaded and thereafter the door closed, but no further operation canthen take place until the fan has been "started.

The means for shifting the header-fall into or out-of engagement to cause belt drive of the tight pulley on the jack shaft comprises an operating lever 89 which with other operating parts is mounted upon a cast bed-plate 98 bolted'to the side sheet of the tumbler housing. Operating lever 89 is pinned to a shaft 9| rotatable in a bearingv forming part of said bedplate casting. Attached to one end of the operating lever is a roller 92 adapted, when the lever 89 is thrown to engage the belt shifting header-fall in operating position, to come in contact with a switch operating arm 93, moving said arm to shift a switch A to initiate the opable bracket may be adjusted radially about the header jack shaft 55. The adjustable bracket I05 is provided with a seat for the pin'I08, and also with a bearing I86 for the extruded hub I 01 of a pinion I08. This pinion meshes with the gear segment 99 mounted, as described, upon the pin I88. Extruded hub I01 of pinion I08 is prevented .from endwise movement by means of a set collar 0 and is provided with a coaxial bore, not shown; through which the reciprocating shaft 68 is free to move. Portions of this extruded hub diametrically opposite each other are removedto form long slots III, providing driving surfaces against a pin through the shaft 68. Thus when the gear segment 99 is moved by endwise shifting of the link 98', the resulting movement of pinion I08 and its extruded hub rotates shaft 68 by means of the pin II 2, no matter at what point in its path of travelthis pin is located. For a clearer disclosure of this structure, reference may be had to aforesaid Patent 2,203,422.

This movement accomplishes the 180 throw of the l eader-fall II and is the means for initiating or terminating association of the tight pulley 59 with one or the other of the driving belts 8|, 82 and thus the rotation of the tumbler cylinder. It will be understood then'that. when the operating lever 89 is thrown toward the center of the tumbler away from the position shown in Fig. 3. the toggle composed of the members 94, 95 straightens out and causes rotation of the interlocking member 96 about its axis of rotation, causing the arm 96 to move and rock the gear segment 99 toward the front of the tumbler. The straightening of the toggle94, 95 locks the operating lever in .the engaged position of. the belt shifter header,

thus insuring that the tumbler drive will continue until the starting lever 89 is returned to its forward or disengaged position.

Safety devices associated with mechanical control mechanism the opening of the shell door I3 when the belt shifter header is engaged and also preventing any actuation of the operating mechanism to start rotation of the drum when the shell door is open.

Referring to Fig. 3. it will be seen that the interlocking member96 is provided with thepro- 'jection 96', as mentioned above, which serves to eration of certain automatic controls, as will be explained hereinafter.

Pinned to the shaft 9| in proper angular relation to the lever 89 is an arm 94, connected form an interlock between the operating lever 89 and the shell door I3. This projection cooperates with a camlike abutment member I23 mounted to move about the axis of the shell door I3. With the lever 89 in the header disengaged position. as shown in Fig. 3, there is no obstruction to the openin and closing of the door I3 due to the projection 96', but it will? be understood I I2 fastened that when the'door is' open a portion of the abutment I23 lies in the path of projection 96, so that the operating lever cannot be thrown from the disengaged position to the engaged position of the header. Consequently the tumbler drum cannot be put into driven condition while the shell door remains open. on the other hand,. when the shell door is closed and the operatinglever 89 is in its rearwardor header engaged position, the projection 96 of the interlocking member lies in the path of another portion of the camlike abutment I23, making it impossible to open the shell door. This arrangement thus makes it impossible, once' the drying cycle has started, to introduce goods freshly laden with solvent and thus upset the control of the air-vapor mixture within the tumbler, a very necessary safety precaution.

Now,'since, as will be shown hereinafter, it, is impossible that the starting lever 89 be put into engagement position unless current is being supplied to the electric control devices, hereinafter referred to, which first necessitates initiating operation of the fan by supplying steam to the steam turbine, it follows that the dryer cylinder cannot be set in operation until after the fan is started.

As will be explained in connection with the wiring diagram, the main electric line through the magnetic starter includes a switch R which is mounted upon the back sheet of the tumbler casing, see Fig. 3, and which is preferably a tilting mercury switch adapted to prepare the magnetic starter circuit so that, after the switch R is closed. the said circuit becomes' manually operable when the fan is in operation. This results from the fact that when the fan is in operation the unbalanced damper 29 will be moved by the air stream from the fan, from its normal shut-01f position closing off the discharge duct, to an open position which will not interfere with the air discharged from the fan. In the closed position of the damper the switch R is open, and in the open position of the damper the switch R is closed. Thus switch R is provided in the starting circuit for the control mechanism in order to be assured that the turbine is started when the steam is admitted to the same and that the fan is in operating condition.

Safety devices operable upon failure of steam to the fan turbine Supported upon the bed plate 90, see Fig. 3,

' is a solenoid I25 to the core of which is attached a weight I26 of suflicient mass to cause the immediate descent of the solenoid core whenever excitation ceases. As will be more fully explained in connection with the wiring diagram,

this solenoid is energized under normal working conditions upon the closing of the magnetic starter, which is indicated inthe drawings by the letters MSand which is shown located on the tumbler housing in Figs. 1 and 3. It should be' understood that operation of the magnetic starter closes the main switch which controls operation of the automatic cycle control devices and that the solenoid I25 remains energized as long as the main switch in the magnetic starter remains latch I21 having an arm I21" maintained by gravity in engagement with a shoulder I26 on the solenoid weight I26 and having another hookshaped arm adapted to cooperate with the interlock 96 to prevent operating lever 89 being thrown'to engaged position unless solenoid I has been energized which, as said above, can only occur if the tumbler fan is in-operation and, as will be shown hereinafter, if the temperature of the air entering the tumbler'from the heater is below a predetermined maximum. Thus it will be understood that latch I21 serves as an interlock against improper operation of the tumbler. When electric power is off, the solenoid I25 being de-energized permits the latch to swing into interlocking relationship with projection 96 so that, if the operating lever 89 be in the disengaged position, it will be impossible to throw it to the engaged position. Should it happen that the lever 89 being in engaged position and failure of current occur, the dropping of the solenoid weight will cause the latch hook to rest against the outer edge of the projection 96 so that as lever 89 is thrown to disengaged position, as it must be to continue further drying operations, for

reasons which will appear later, the latch hook dropping under projection 96 interlocks therewith and prevents further operation of lever 89 until current has been restored.

Also pivotally mounted on the bed-plate an adjacent the solenoid is a latch I28 which functions only upon failure of current to prevent opening of the shell door I3 until current has been restored, which, as has been pointed out, can only be after the temperature of the air entering the tumbler from the heater falls below a predetermined maximum. Latch I28 cooperates at one. end with a shoulder I26 on the solenoid weight I 26, and at the other end is provided with a hook for interlocking action with a coacting abutment member I23 movable with the member I 23 about the door hinge axis. When current fails, the dropping of the solenoid core, which has been holding the latch I28 out of engagement with door member I23, now permits latch I28 to swing under the action of gravity so as to interlock with the door member and preventopening the door until current is restored. This latch never serves to prevent closing the door.

, Thus it will be understood that irrespective of the period inthe drying cycle that current failure may occur,'the drying tumbler will be put out of operation and/or held out of operation until after current'is once more flowing through the main switch. to the control devices, which necessitates that the fan'be in operation. Another safety element related to the solenoid I25 is a switch K which will-be referred to hereinafter when its function will be explained in connecsolvent remaining in theclothes. after centrifugal, extraction is evaporated and driven off from the batch in the dryer drum. A' high heat period and a cooling period have been mentioned and have been found to be advantageous in carryas electrically operated timers, a magnetic switch contactor, and certain other switches not hereinbefore mentioned.

The magnetic starter MS has been mentioned,

to terminate the low heat period of operation,

and operates again to terminate the high heat 'period of operation. After its second operation the half-turn motor will have returned to its initial position and be maintained in condition to tion-of the half-tum motor and the timersLHT;

andHHT need nothere'be repeated since these are fully described in the aforesaid patent,

Win'ng' diagram v I Again referring to Fig. 8, the wiring diagram will be seen to embrace the various pieces of equipment heretofore mentioned. It comprises the single pole double throw switch A mentioned above as associated in operation with the header operating lever 89, the single pole double throw switch 3 operated by the half-turn motor, the

two electric timers, the solenoid I25, the halfturn motor P, the fan actuated switch R, a thermostatic switch F which is controlledby the temperature of the air entering the tumbler from the heater, a magnetic contactor J interlocking center circuits; a single pole single throw manually operated selector switch M, and a single pole single throw switch K operated by the solenoid I25.

may not easily be tampered with. Mounted on top of this box are three pilot lights which indicate certain stages of the cyclic operation of the apparatus, but which will not be referred to again in this specification.

The thermostatic control switch F is operated by a suitable bulb I64, located in' the air passage leading irom the heater to the interior of the tumbler housing at a suitable location for nieasurmg the temperature of the air after it has passed through both heater units and is about to be brought in contact with the materials within the dryer drum.

Referring to the wiring diagram, LI and L2 indicate a single phase power line entering the magnetic starter MS. It will be seen that the line LI, at a. point ahead of the magnetic starter, is connected by the switch contact arm AI in the upper position thereof, through swfich contacts A2, A3 to the starting button, marked Start, of the magnetic starter. This connection only obtains when the header engaging lever 89 stands in its forward or disengaged position. Switch R, ,hereinbefore referred to, is located in a circuit between the stop button of the magnetic starter and the coil I66 of the starterso that, when the start button is pressed, a circuit to energize the coil I66 of this starter is established from line LI through switch A, throughthe start and stop buttons of the magnetic starter, switch R, through the coil I66 to L2. Energization of the coil I66 will close the main switch contacts I61, I68 and thereafter the magnetic circuit is maintained by a jumper I69 connecting LI into the starting circuit at a point between the start and stop buttons. Clos- '.ing the main switch contacts I61, I68 provides a circuit LIA, L2A to the control mechanism including the timers and half-turn motor P. The line LZA contains a suitable thermal element III for overload protection.

It will beunderstood from what has been said that, tobegin operation of the tumbler, the

the magnetic starter MS which is preferably p'rovided with overload and low voltage protection,

For economy in mechanical operation and wirr ing, switeh B' and other switches, not pertinent to the present invention, are enclosed in a single switchbox I43, best seen in Fig. 5. Switches A and M are located in a single box I, see Figs. 1 and 3. Also three pieces of equipment, the low heat timer, magnetic contactor J and the thersuitable-box I63 mounted upon the rear portion of the topof the tumbler housing. This box is preferably equipped with a look, not shown, since the low heat timer and thermostatic switch F are mostatic switch F, are located together within a steam valve ,3I must be open, admitting live steam to the turbine. This starts the fan in operation and, as soon as a suitable air flow has been set up through the heater and tumbler,

movement of *the unbalanced damper 29 will close the switch R. It will be understood at this time that the heater is under the control. of the thermostatic valve 43. It will be seen also that after the closing of the switch R and the The switch F is normally held in an open position at temperatures above the selected temperature at which the apparatus is to operate during 'the low heat period, as, for instance; ,F. If, at the beginning of a cycle. the temperature stands below or at 1 :0 F., the switch F will be closed and a circuit will be completed from LIA through switch K, through the coil of the magnetic contactorJ and back to line L2A. Thus the magnetic contactor will be energized and, drawing up its core, will complete a circuit by way ofswitch contacts J3 and J4 through the coil of the solenoid I25 and will also complete a circuit by way of magnetic contacts J I and J2 through its own operating coil. Thus the solenoid I25 will become energized and, by

the raising of its core, open the circuit through the switch K, so that thereafter the coil of the magnetic contactor -J is maintained in an energized condition solely through the maintaining circuit including-the contacts, JI, J2.

Referring to Fig. 3 will show the switch K as located closely adjacent the solenoid I25 upon the side of the tumbler housing. The solenoid weight I25 is provided with a shoulder I26 having a cammingsurface for engaging roller I14 carried by a lever I12 pivotally supported at I13 on the box of the switch K. This lever is provided with an adjustable bolt I15 adapted to engage the push button KI of the normally closed switch K. This switch is merely a, push button switch of a 'well known type biased normally to closed circuit condition. When the,

solenoid is engaged, the engagement of the adjustable bolt with the push button KI opens the circuit through switch K, which no longer is needed since the magnetic contactor J is now self-maintained, as mentioned above.

It will be remembered that-with the solenoid Low heat period of operation As previously explained, when the operating lever 89 is thrownto start the drying cycle, this operates switch A through roller 92 and operating arm 93, causing the contacts A2, A3 to be broken, and the contacts A4, A5 to be made.

- Thus a live circuit. is established to the switch '3 if the selector switch M is closed. This sebrush P2 passes fromthe segment P4 to the segment P5, the motor is connected directly in circuit with line LIA so that for the rest of its half-revolution the motor is energized from LIA through the motor coils and back to HA. At the end of the half-revolution the brush moves ofl' segment P5 onto segment P6 which at this time is not connected with the line LI The half-tum motor accordingly stops at thispoint.

High heat period of operation When the half-tum motor thus makes its halirevolution, it starts the high heat period of the drying cycle by opening valve 38 and admitting live steam to 0011 20 of the secondary heater I1. It also operates switch B, as will be explained hereinafter. Thus the secondary heater, which up to this time has received no steam from any source, now receives steam to its coil 20 directly through the mechanically operated valve 38. The flow of steam in the exhaust line leading to the coil I9 of the primary heater I6 has, as was said above, been under the control of the thermostatic valve 43. The thermostatic valve will continue to operate so long as the temperature existing in the measuring chamber 2I does not exceed the predetermined temperature of the low heat period so that, after the operation of the mechanically operated valve, the primary heater receives whatever steam is passed by the thermostatic valve while the secondary heater becomes highly heated by the high pressure steam now passing through its coils. When the half-turn motor operated to change from low heat to high heat period, it operated switch B to break contacts B4, B5 and make contacts B2, 133.

When the live circuit through B4, B5 was broken, the low heat timer was tie-energized and,

' through spring action, the timer was automatilector switch'M is, as noted above, located in' the same switch box I with the switch A, but is manually operated and is only opened when drying certain types of garments adversely affected by high temperatures. understood that with the switch M open, the apparatus will not operate through the different stages of the drying cycle, but may be operated for an indefinite period of time under the conditions of the low heat period, with the temperature maintained at thetemperature for which the thermostatic valve 43 is set. 5

Assuming, therefore, that the switch in is closed, the live circuit continues through contacts B4, B5 of switch B, to the low heat timer LHT by means of a line I18, and through the timer-back to line L2A by means of wire I11. Thus the low heat timer is set in peration concurrently w h the throwing of the operating lever as. Having established previously by test that the low heat 'period shall be, say, ten minutes, after ten minutes have elapsed from-the throwing of the oper-;

It will be readily cally reset to zero ready for the beginning of another cycle. The wire I19 now being alive through closure of switch contacts B2, B3, current flows to the high heat timer HHT starting the latter to control the period of high heat operation. After a time, the determination of which has been established by test, switch D in the high heat timer is closed completing a circuit through wire I" to contact P6 of the half-turn motor which becomes energized and makes a second half-revolution back toits original position and, in so doing, closes the valve 38 thus cutting off the steam supply to the secondary heater. This restores the steam control to the condition desired during the ensuing cooling period and at the beginning of the next drying cycle. This reversal of the halftu'mmotor from high hea to low heat is the bebinning of the final or c The second half-revolution of the half-turn motor shifts the contact member BI of switch B, breaks the circuit between B2 and B3, I and reconnects contacts B4 and 35. Thus. the high heat timer is de-energized and returns to zero position. During the high heat period or operation, the temperature of the air passing through the tumbler may be carried well above 200 F. because by this time only a small amount of solvent remains in the clothing and it is thus impossible to develop an explosive mixture in the drier.

If for any reason the header enga in lever be thrown to its disengaged position during the low heat period, the low heat timer will imme- I diately be thrown outof action and will return to its initial position. Also, lithe lever I! be mam; to diseng ed position during the high heat De; riod, switch contact AI, by bridging contacts A2,

period of the cycle.

Cooling period of operation Under some conditions the cycle of operations might terminate here, but it has been found in practice that the time usually consumed to unload and reload the tumbler is insufiicient to cool the tumbler to a temperature below the flash-point of high heat to the cooling stage. The thermostatic valve 43 may or may not be open when live steam is being supplied to the secondary heater, depending upon the temperature existing in themeasuring chamber 2I.

It should be noted that the steamvalve 40 is included in the piping system only as a manual means for admitting live steam to the tumbler at the beginning of the operating cycle. This is done to make the operation of the tumbler conform,

' if found desirable, to a long established practice the solvent, that is, below themaximum temperature established for the low 'heat period. It has been found desirable, therefore, in order to secure complete safety, to introduc a cooling period immediately succeeding the high heat period in order that the temperature of the ,air entering the dryer may reduce to the temperature set- .(ting of the thermostatic switch F;

During the cooling period a reduction of the temperature of the air entering the drum takes place, since the secondary heater is nolonger operative. When the temperature is lowered to the setting of the thermostatic switch F, this switch closes and the apparatus is ready to begin a new cycle, after. the operator has thrown his operating lever to disengaged position, opened the tumbler door, and replaced the load in the turnbler drum with a fresh load requiring drying. I

As said above, switch B is actuat'ed by the halfturn motor P. The-switch B is a shiftable switch contained in the box I43 located adjacent the half-turn motor P at the top of the tumbler. Mounted-on an extension of the half-tum motor shaft P2 is a cam IBI mounted on a shaft I83. Suitably supported in theframework of the motor" assembly is an operating'arm I84. At one end, arm I84 is equipped witharoller I86 contacting cam I8I and at the other end with an adjustable stud I81 contacting a push button of the switch B located in the switch box I43. Thus the cam I8I elevates the roller I86 and depresses the other end of the operating arm I8}! when, at the end of the low heat period, the half-turn motor makes its first half-revolution, thus depressing the button of switch, B and changin switch from its low heat position to its high heat position and, when .the half-turn motor makes its/second half-revolution to change the tumbler fr m the condition for high heat-to the condition for cooling, the said cam moves the operating arm I84 to permit restoration of switch B to its original position with contacts B4, .85 made and contacts B2, B3 broken. A more complete disclosure and description of the timers, the halftum motor, and the said cam operating mechanism for'switch B as well as for certain signal controlling switches, omitted herein, may be had by reference to the said Patent 2,203,422.

In the operation of the tumbler the main shutoff valve 3| is manually operated and is used only to turn on or shut off the steam supply to I the tumbler and to the stream turbine. The lever operated valve 38 is ed by the half-turn motor every time th automatic drying cycle changes from low heat to high heatconditions, and is closed again when the half-tum motor is called upon to change the tumbler operation from of some cleaners, by admitting steam for a few moments at the beginning of the. operating cycle to prevent the accumulation of an abnormal amount ofstatic electricity, a condition which might develop when drying such material as silk, particularly in cold weather.

It will be noted from the above that from the present construction are eliminatedall devices for supplying steam to the interior of the tumbler or blowing a whistle in the event of current failure since, with a fan driven b a steam turbine, current failure would have no effect upon the flow of aii th'rough the tumblenunless simultaneously there were failure of steam as well. Live steam at a sufficiently high pressure for efficient operation of the turbine, say'90 pounds to the square inch, will provide exhaust steam at a suitable temperature to maintain the air leaving the primary heater at the desired temperature below flash-point. Should there be any excess of steam in the exhaust line so as to raise the temperature of the thermostatic valve to the closing point of said valve, the excess of pressure in the exhaust steam line will be taken care of b the back pressure valve3'l which, as was pointed out above, is located in the turbine exhaust line beyond the connection of that line with the thermostatic valve 43. The surplus, of exhaust steam may be used for any low pressure accomplishment. Should there be a failure of steam to the ually cool permitting the operatorto remov the batch or not, as he might desire. However, since with the opening of the switch R the solenoid I25 would be de-energized, although it would be possible to move the operating lever 89 to its disengaged position and stop rotation of the tumbler, it wouldnot be possible to raise the tumbler door I3 until current is again restored to the solenoid I25 and, as said above, this could not take place until the temperature within the tumbler falls to a point permitting the closing of the switch F."

As many possible embodiments may be made of the above invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accomtions, a fan driven independently of said cylinder driving means for moving a current of air through said tumbler, an electric circuit including circuit controlling means operatively res portsive to the passage of air through said fan, and electric means interconnected with said circuit cooperative with said operating means for said control means to prevent starting cylinder rotation unless said circuit control means isfunctioning to energize said circuit.

2. In apparatus of the character set forth, in

combination, a tumbler housing, a rotatable cylinder in said housing, driving means for said cylinder operatively connected with a source of power, control means for said driving means,

means for operating said control means having cylinder operative and cylinder inoperative positions, a driven fan operated by power froma source independent of the sourceof power for said cylinder drive for moving a current of air through said tumbler, a-movable member located in the air stream of said fan, an electric circuit including circuit controlling means operable by said movable member, and electric means in said circuit cooperative with said operating means for said control means to prevent starting cylinconnection, means connecting said secondary heater with said steam supply connection, and means independent of each other for controlling the steam supply to the respective heaters.

4. In apparatus of the character described, in combination, a drying chamber, steam driven means having relatively high and low pressure steam supply and exhaust connections, a fan driven by said steam driven means for causing a current of air to pass through said drying chamber, heating means for said air comprising a primary heater and a secondary heater, means connecting said primary heater with said exhaust connection, means including a control valve connecting said secondary. heater with said steam supply connection, and time controlled operating means for said control valve.

5. In apparatus of the character described, in

combination, a drying chamber, steam driven means having relatively high and low pressure steam supply and exhaust connections, a fan driven by said steam driven means for causing a current of air to pass through said drying chamber, heating means for said air comprising a primary heater and a secondary heater, means connecting said primary heater with said exhaust connection, means connecting said secondary heater with said steam supply connection, means for controlling the steam supply to said secondary heater, an electric circuit including automatic devices to effect operation of said controlling means, a movable member located in the air stream of said fan and movable by said air stream, and means in said electric circuit operable by said movable member to render inoperative said electric circuit and included automatic devices.

, WILLIAM STROBRIDGE.

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