US3132005A - Clothes dryer condensing system - Google Patents

Description

y 5, 1964 s. L. MCMILLAN 3,132,005

CLOTHES DRYER CONDENSING SYSTEM Filed March 13, 1961 Jul Em STEPHEN L. M MILLAN ATTORNEY CLOTHES DRYER CONDENSING SYSTEM Stephen L. McMillan, Wheaten, IlL, assignor to General Electric Company, a corporation of New York Filed Mar. 13, 1961, Ser. No. 95,107 4 Claims. (Cl. 34-54) The present invention relates to clothes dryers which include a closed cycle condensing system and more particularly to an improved construction and' control of the condensing system.

It is therefore an object of the invention to provide an improved and simplified condenser construction and control system. for a clothes dryer.

It is a further object of the invention to provide in a closed" cycle condenser dryer system, a dual purpose high temperature thermostat which responds either to malfunctioning of the heaters or to an overflow of liquid in its condenser chamber. I e

It. is a further object to provide a simplified shut-off mechanism for a dryer, whichresponds to an overfill of liquidiinithe condensing chamber of a clothes dryer to stop tlie dryer operation. It is; known that in a condensing clothes dryer, a heated lair how is used to evaporate moisture from the clothing, and subsequently the moisture is condensed from the air by means of cool water which is introduced into contact with the heated air within the dryer cabinet. The resultant, liquid is discharged to drain either by gravity or by a" pump. Itwill beapparent that" should the outlet drain or the pump become clogged, the continued flow ofcondensing water could flood the clothes dryer with obvious undesirable results. e v I To alleviate this difficulty in a water condenser clothes dryer or the like; the present invention contemplates a li'quidcontrol means wherein a control circuit is provided in combination with circuit interruptingmeans responsive toa predetermined liquid level in thecasing or container for the liquid, whereby the operating circuit for the dryer is' rendered inoperative should the liquid in the casing or container reach a predetermined level because of clogging ofthe discharge opening therefor; or failure of the pump, if such be used in the apparatus.

'I he'circuit [interrupting means utilized as the preferred control herein is the thermostat common to clothes dryers as the high temperature thermostat required by most safetyicodes to interrupt at least the power to the heating element in the circumstance ofunduly. high tem pera t ure s. The thermostat in addition to its normal use controls the maximum condenser water level in that the air which iscirculated over-the heaters to extractlheat therefrom and maintain them at. a safe operating temperature is channeled through the condensing chamber. The chamber is so constructed that an excessive quantity, of liquid in the condensing chamber willshut off the air flow; consequently the heaters will overheat and the thermostat will operate to open the power circuit.-

To be more specific about. the constructionof, the condenser chamber, the condensing chamber includes one Qlf more baffles forcing the air flow into a serpentinep'ath'. Them a'in bathe depends from the chamber ceilingto-a predetermined height.

the chamber reaches this. height, an elfective barrier tothe flow-.of'air. is formed by the combination of bafile and water below it. This barrier will tend toblock or interrupt theflow. of air tothe heaters, whereupon the heaterswill, as mentioned, overheat andtrip thehigh tempera ture thermostat. In the preferred circuit combination, the tripping of the thermostat will open the circuitsto the dryer drive motor, the timer motor, the air heaters and,

the water inlet control and as a result the dryer will bedeenergized pending a manual resetting of dryer control mechanism.

It should be noted that the machine operatormay reset the dryer without correcting thefault and operation be resumed the thermostatheats sufiiciently to re-open the iopenative circuits. Persistenceih restarting object.

The invention both as to itsorganization and principle;

, along the line'2-2 of PEG. 1;

lower right" corner of would conceivably cause the machine to overflow; however, the shut-oh level in the condenser chamber {may be so related to the capacity of the chamberthat' shutoff will occur at but a fraction of the capacity of the condensing chamber; It is a further feature of the invention that the co'ndensing chamber is'constructedtoallow ready access to its interior for the purpose of freeing" the drain by removal of the obstructing material or of operation, together with further objects and'advan-' tages thereof, will best be understood by reference to the following specification '[flkI1lIl' 'COIlHCtlOI1 with the accompanying drawings in which: I V V FIG'.'1 is a front perspective view of a clothes dryer. utilizing my invention with the outer walls shownin outline and portions broken away; f F

FIG. '2 is a sectional side view of the dryer viewed FIG. 3 isa side view inlcross section ing chamber; 1 v j FIG. 4 is' a schematic wiring diagram of the control ortheec dens;

circuit incorporated in theid ryer of FIGS; 1- and 2; and

. FIG. 5 is a'partial'side viewas FIG; 2. shoWi'ngI-the door removed. i v j v Referring now detail to the-dryer 10 of F Ki s. 1' and 2',l the dryer there shown is of the type known'as Axial Flow. In dryers of this type there is, an imperforate I walled cylindrical drum v12}, journalledlto rotate-on a Whenthe level of water within" horizontal axis within a substantially imperforateQ appear-ance oahinet 14; The drum includes. teamm te. perforations 16 about its rear wall 18 and a ceritraluaccess opening 20 in-its front .wall..22; Adjacent andoutwardly of the opening'20,.'thecabinet14 is ported with. a cabinet access opening 24 which isnorrnally covered by: a side hinged. door 26. Door. 2'6.is pivotal hetjween-sa closed position denyingaccess to. the-druin interior and: an open position allowing free entry to the drumiinterion to allow loading of the drum. 1

The dryershown, further is of-the reoircu-lator'ytype. which afloW'ofP air is heated, passed through "the drum under suction pressure irom a blower andpiassed through a v treating chamber for return-flow throughvthe system. Within generally described systern there are positioned a plurality of radiant heaters 30; which are secured to. anannular stationary plate 32*concentuie to and outwardly spaced from the reardrumwall. These heaters will heat air in circulation just priorto; entry into the drum via thevinlet. perforations 16 in the drum rear wall. To exhaust lair fromthe there pro vided adjacent the drum fron-topening a downwardly directed duct 34 which serves to ohannel exhausted air to' the rotary blower 36. Airlis emitted suadially fromthe; blower to a. horizontal duct 38 which leadsimo onejend of the essentially reotangularcondensing chamber 40. At

. the opposite end of the condensingoharnber, .thereiis anexit air duct 42 which is upwardly positionedto direct;

v the exit firom the condensing chamber-"past the-heaters for'reciroulationto the drum. j 3

the dryee. there is provided a main drive meter SO mounted-toV the oabinet basestruotlire (not shown and whichby-ob; v-ious and generally known mechanical expedients such as; pulleys and the like rotates blower 36, drum 12 and also the dryer with the trouble access r form a starting circuit which restores on release of manual pressure and must be reset for further operation once the circuit has restored. In series with timer switch contacts 96 and door switch 98 is the high limit thermostat 104 which nominally may be called the safety thermostat.

This thermostat remains closed at all temperatures below a high, safe temperature such as 260 F. This thermostat prevents excessive overheating of the machine and will open the operative circuits to the machine in any situation productive of this excessive temperature. Such a thermostat will normally be set to re-open at a lower temperature such as 220 F. The physical positioning of thermostat 104 may be seen in FIG. 2 mounted to the flange of annular stationary plate '32 in the area above heaters 30. The thermostat will sense the temperature of air at the heaters .and will rapidly respond to changes in air tem- 97 shortly before the cycle termination to allow a final,

non heated, non-condensing cool-down vperiod. During this'cool-down period, the timer controlled contacts remain closed allowing thedrum to tumble for the re mainder of the preset time. V

' The operationof the invention has follows: The wet clothes to be dried are placed in dr-urn12, and door 26 is closed, closing door switch contacts ,98. Knob 78 is rotated to the position indicating the cycle duration required This rotation of the knob closes contacts 92 and'96. Knob 78 is then depressed closing momentary contacts 102. Qlosure of'the momentary switch completes a 118 volt circuit to the drive motor and to the timer motor. These motor starting circuits may be traced firotn lead N through the parallel paths including inthe first path start winding80 and motor contacts 84, and

in the second path run winding 82 of the drive motor and-through the third paral'lel path including the winding of timer mot-or 94; through the multipleconnectionto momentary contacts 102, door switch contacts 98,

thermostat 1-04, and closed contacts 96 to lead L2. Drivev motor 50 accelerates and tn'ps its centrifugal switch contacts 84, which opens the circuit to the start Winding 80 and locks the run winding 82 over a hold path bypassing momentary contacts 1-02. Momentary contacts 102 then restore. The timer motor 94 and run winding 82 of the V 6 pump 64 which, as previously described, is operated by drive motor 50. I I

The comparatively dry ,air then passes under bathe 72, which optimally extends for the full-width of the condensing chamber 40, and out air vent 74 for recirculation past heater and high temperature thermostat 104 into the drum. This cycle continues until air temperature at thermostat 90 rises above the acceptable operating, and the thermostat opens its contacts to deenergize heater 30. The temperature drops and thermostat 90 reoloses its contacts. Thermostat 90 cycles the heaters in manner for the entire timed period. At the conclusion of the heat dry period, timer contacts 92 and 97 restore; Contacts 92 open the heater circuit, and cont-acts 97 restore the solenoid, 68' shutting off the how tonozzl'es 66. The motor continues tumbling the clothes for a cool down period after which timer 94 having completed its cycle opens contacts 98 to deenergize timer motor 94 and the drive motor run winding Drive motor 50 slows down and eventually stops its rotation. Contacts 84 and 86 restore on slow down of the-motor and th circuit is thereby returned to normal.

With a closed air flow system'as shown;- blockage of air flowdue to any cause, cause the heaters to overheat, there being no air circulated to carry olfthe heat generated. As a result the temperature at the heaters mounts very rapidly. On this temperature rise, thermostat 104 operates its contacts to the open position deenergiz-- ing the circuit to the motor winding. The drive motor slows down and opens speed responsive contacts 84 and 86. The opening of these contacts shuts" down the four to five inches.

A blockage or interruption of airflow may also occur due to an accumulation of lint in filter screen 56 impeding the air flow. In this latter event the machine operator may readily see that the machine is not operating and that the cycle has not concluded. On inspecting the lint screen 56 and finding it full, the operator would empty the lint filter and thenreset the machine. i

The other most probable cause of trouble inthe machine is that which may follow an accumulation of lint or" other matter the chamber 40. This may clog drain 62 and cause condensingjliquid to rise within chamber 40. Previously, diaphragm switches responsive to the increase in liquid level have beenused as shut-off switches. The operating environment of suchswitches is incompatible with uniformity and accuracyof response, for there is at most, an available water head of only The limited head pressure makes it necessary to employ a very sensitive diaphragm switch, and it has been the general experience that such switches .lead totalse indications of difficulty and unnecessary service calls.- The present'invention alleviates the necesdrive motor are then looked operated. As motor 50 is accelerated, contacts 86 also close completing the circuit to the heaters through closed thermostat 90 and timer contacts 92. The heaters heat the circulating air as the a drum. rotates fora short period hollowing which con tacts 97 close initiating the condensing action.

As mentioned previously, is circulated by the blower through a closed cycle including'the condensing chamber, inlet duct, heating area, tumbling drum, exhaust duot and hack to the blower. In this way air is heated at the heaters and is passed through the drum which is being rotated to tumble the wet clothes therein. Heated air contacts the tumbling clothes and absorbs moisture from the clothes. This wet exhaust air leaves the drum throughthe front access opening and enters the exhaust duct 34. The screen 56 catches lint borne in the air and allows the moist air to be conducted through blower 36. The air is then emitted through duct 38 past thermostat 90' and into the condensing chamber. There, the hot, moist exhaust air meets the spray of cooling water from nozzles 66 and the moisture condenses out. This condensate is drained out drain pipe 62 by the action of drain sity of use of a pressure diaphragm and utilizes the high temperature thermostat 104 as the water level sensor. An overfill of Water in the condensing chamber will cause a water buildup at least to the lower edge of baffle 72.

Such an overfill will form-Ia barrier covering the free area below bafile 72 and will block the air how out of the chamber. Blockage of air, flow will result in an excessively high temperature conditionwat thennostat 104, causing opening ofthe thermostat contacts 104, andsubseq-uent machine shut-off. Thus, the baffle and excessive water level combine to block air flow on'a high'water conditionin the condensing chamber. o

It should be noted that the water retentive capacity of chamber 40 is sufliciently great that following amalfunotioning, shut-oh and subsequent reset, the chamber can retain the excess of water without flooding. On reset, the condenser solenoid does not operate for a period during which heated is circulated and if prior'to the conclusion of this period the blockage has not corrected itself, the machine will continue to overheat and shut oil.

To allow service accessibility to the drain pump and 7 condensing chamber, a small [access opening 108 has been provided in the side of the cabinet wall asshown in FIG. A door (not shown) may be hinged or held by screws to cover the opening in .any suitable manner allowing easy removal. Oniiremoval of the door from opening 108, the condenser chamber 40 may be approached easily. The condenser chamber contains a door 110, secured in suitable fashion to the chamber wall to seal the chamber firom leaks. The lower extent of this door optimally should be above the lowerlevel of baffle 72 to prevent wa ter overflow on removal of door 110 in case of trouble. I This condenser door 110 may be reached following removal: of cabinet door and removed to allow the d'arin pipe 62 tobecleared of obstructions when necessary. Needless to say, both the inner and outer doors should be replaced completely prior to re-operation of the machine.

7 While there has been described what is at present considered to heme preferred embodiment of the invention,

it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of 1 the invention.

What is claimed is: a

1; A laundry dryer comprising an external casing having a loading opening in a wall thereof, 7

a clothes-receiving drum mounted for rotation within said casing, a firont wall of said drum having an opening communicating with said loading opening and a rear wall provided with a plurality of air inlet Orr-wings, v

structure within said casing forming a heating chamber openly facing said drum rear wall,

electric resistance heating means in said chamber, a

structure providing a duct communicating between the front end portionof said drum and said heating chamber, said duct including a horizontally extending condensing chamber having a bottom wall configurated to fiorin a sump communicating with an outflow pipe,

means comprising a cold water inletpipe and at least one spray nozzle arranged to discharge cold water into said condensing chamber,

a normally closed valve in said inlet pipe,

a solenoid arranged on said valve, 1

a blower for enforcing air flow in a closed circuit sequentially through said heating chamber, said drum, and said condensing chamber, in a quantity sufiicient 'to maintain air temperature in said heatingchamber below :a predetermined minimum,

a motorfor drivingsaid blower,

a bathe in said condensing chamber arranged rupt said air circulation upon a predetermined increase in water level within said chamber,

- an electric circuit common to said solenoid and said motor for energizing the same,

7 means fior completing said last-named circuit,

I and athermostat responsive to air temperature in said heating chamber to open-said circuit upon sensing v a temperature above said predetermined minimum, wherebysaid water inlet valve will close and said motor will be deenergized- 2. Alaundry dryer comprising an external casing having a loading opening in a wall thereof,

- -a clothes-receiving drum mounted for rotation within said casing, said drum having at one end an opening communicating with said loading opening and at its opposite end being provided with a plurality of air inletopenings, structurewithin said casing forming a heating chamber openly facing said air inlet openings, 7

electric resistance heating means in said chamber, structure providing a duct communicating between the front end portion of said drum and said heating energization thereof to opento interchamber, said duct including a condensing chamber disposed wholly below said heating chamber, said condensing chamber having a bottom wall configurated to form a sump communicating with an outflow means comprising a cold water inlet pipe and at least one spray nozzle arranged to discharge cold Water into said condensing chamber,

a normally closed valve in said inlet pipe,

a solenoid arranged on energization thereof to open said valve,

a blower ,cfor enforcing air flow in a closed circuit sequentially through said heating chamber, said drum, and said condensing chamber, in a quantity suliicient to maintain air temperature in said heating chamber below a predetermined minimum,

a motorfor driving said blower,-

a bathe extending across said condensing chamber intermediate the inlet and outlet ends thereof, said baffle terminating above said chamber bottom Wall to interrupt said air circulation upon a predetermined increase in water level said condensing chamber,

an electric circuit oommonto saidsolenoid and said motor forenengizing the same,

means for completing said circuit,

and a thermostat disposed in said heating chamber above the heating means therein to open said lastnamed circuit upon sensing a temperature in said chamber above said predetermined minimum, whereby said water inletvalve will close and said motor will be deenergized.

3. A laundry dryer comprising an external casing having a loading opening in a .wall thereof,

a clothes-receiving drum mounted for rotation within said casing, afront wall of said drum having an opening communicating I with said loading opening and a rear wall provided with a plurality of air inlet openings,

structure within said casing forming a heating chamber openly facing said drum rear wall,

electrically activated means for increasing the air temperature in said heating chamber,

, structure providing a ductcommunioating between the front end portion of said drum and said heating chamber, said duct including a condensing chamber having a bottom wall coniigurated to form a sump communicating with an outflow pipe,

means comprising a cold Water inlet pipe and at least one--spray nozzle arranged todischarge cold water ',into said condensingJchambe-r, I

' a normally closed valve in said inlet pipe,

a solenoid arranged on energization thereof to open said valve,

a blower for enforcing air flow in a closed'circuit sequentially through said heating chamber, said drum, and saidcondensing chamber, in a quantity suflicient to maintain air temperature in said heating chamber below a predetermined minimum,

an energizing circuit for said electrically activated air heating means,

a motor for driving said blower,

a switch in said energizing circuit, said switch being arranged for operation by said motor from a normally open to a closed circuit condition as said motor reaches a predetermined speed, i

a baffie in said condensing chamber arranged to interrupt said air circulation upon apredetermined increase in water level within said chamber,

an electric circuit common to said solenoid and said motor for energizing the same,

means for completing said circuit,

and a thermostat responsive to air temperature in said heating chamber to open said last-named circuit upon sensing a temperature above said predetermined minimum, whereby said water inlet valve will close a clothes-tumbling drum therein,

duct means establishing a recirculating air-flow circuit i which air is drawn from said drum and returned thereto,

said air-flgow duct means including a condensing chamber having air inlet and air outlet passages com municating with said drum,

means for enforcing air flow through said duct means,

electric resistance means for adding heat to the recircu- 'lating air prior to its return to said drum,

means including a water spray device adapted to be connected to a cold water supply for introducing a cold water spray into the air traversing said eondensing chamber,

means communicating with said chamber for removing water therefrom,

imperforate bafile means extending across the interior of said chamber upstream of the air outlet passage thereof, said baffle means terminating above the base of said chamber to provide therewith an air-flow passage only so long as said bafile is not immersed in Water within said chamber,

solenoid operated valve means for controlling water flow to said spray device,

an energy circuit for said valve means,

and a thermostatin said energy circuit, said thermostat being disposed in said air flow circuit and responsive to a predetermined increase in temperature of air therein to interrupt said energy circuit. I

References Cited in the file of this patent UNITED STATES PATENTS 2,577,104 Butler Dec. 4, 1951 2,644,245 Hammell July 7, 1953 2,654,160 Peterson Oct. 6, 1953 2,680,914 Smith June 15, 1954 2,722,057 Pugh -2- NOV. 1, 1955 2,858,621 McMillan NOV. 4, 1958 2,878,580 Hughes Mar. 24, 1959

Claims (1)

1. 4. A CONDENSING TYPE CLOTHES DRYER, COMPRISING: A CABINET, A CLOTHES-TUMBLING DRUM THEREIN, DUCT MEANS ESTABLISHING A RECIRCULATING AIR-FLOW CIRCUIT IN WHICH AIR IS DRAWN FROM SAID DRUM AND RETURNED THERETO, SAID AIR-FLOW DUCT MEANS INCLUDING A CONDENSING CHAMBER HAVING AIR INLET AND AIR OUTLET PASSAGES COMMUNICATING WITH SAID DRUM, MEANS FOR ENFORCING AIR FLOW THROUGH SAID DUCT MEANS, ELECTRIC RESISTANCE MEANS FOR ADDING HEAT TO THE RECIRCULATING AIR PRIOR TO ITS RETURN TO SAID DRUM, MEANS INCLUDING A WATER SPRAY DEVICE ADAPTED TO BE CONNECTED TO A COLD WATER SUPPLY FOR INTRODUCING A COLD WATER SPRAY INTO THE AIR TRAVERSING SAID CONDENSING CHAMBER, MEANS COMMUNICATING WITH SAID CHAMBER FOR REMOVING WATER THEREFROM,

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