GB2115127A

GB2115127A - Household laundry drier with condensate collection

Info

Publication number: GB2115127A
Application number: GB08300829A
Authority: GB
Inventors: Georg Kirmes
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-02-09
Filing date: 1983-01-13
Publication date: 1983-09-01
Also published as: GB8300829D0; DE3204396A1; DE3204396C2; GB2115127B; NL8204958A

Abstract

A household laundry drier comprises a collecting container (KS), which is arranged at the top of the drier and withdrawable towards the operating side, for condensate from a catching container arranged below condensing equipment. The condensate is pumped up by means of a pump (P), driven by an electric motor (M), from the catching container, which is arranged at the bottom of the drier. The drier includes level-signalling equipment (N) and means controlling the pumping-out of the catching container to at least be able to be prepared even when the drying program has been terminated or shortened in consequence of the responding of the level-signalling equipment. The level-signalling equipment (N) comprises a change-over switch (w), the output lines (A1, A2) of which are connected to the pump motor (M) on the one hand and to a switching stage (S) on the other hand and which in one output line (A1) and in a cross- connection (Q) from the motor (M) to the other output line (A2) has alternately conducting switching paths (s1, s2) interrupting the cross-connection (Q) when the catching container is empty. Also provided in an end position monitor (T), which completes the circuit for the motor (M) when the collecting container (KS) is properly inserted and which includes a switch (t) to complete the circuit for the switching stage (S) when the collecting container is withdrawn. <IMAGE>

Description

SPECIFICATION Household laundry drier with condensate collection The present invention relates to a household laundry drier and has particular reference to a drier with condensate collection.

In DE-OS 2933513 there is disclosed a laundry drier in which the drying program is interrupted or moved into a cold air phase as soon as levelsignalling equipment in a condensate catching container has responded. The simple interruption of the drying program can be harmful to the laundry, because the heat stored in the system can now be concentrated on individual items of the laundry at rest in the drum of the drier.

A fault indication (optical and/or acoustic signal), which is activated simultaneously on the response of the level-signalling equipment, will frequently cause the operator to empty a collecting container of the drier immediately. After re-insertion of the collecting container, the drying program remains interrupted or in the cold air phase. Since monitoring of the withdrawal of the collecting container is not provided, the program course cannot be further influenced at this instant.

Resumption of the drying program would, in the case where a time ciontrol is present, present to the operator, who is unaware of the degree of drying achieved in the meantime, an insoluble problem with respect to preselection of a new time. Moreover, a switching measure, which cancels the blocking effect of the level-signalling equipment in the catching containerforthis step, would entail increased complexity.

There is accordingly a need for a household laundry drier which avoids the disadvantages of the state of the art, such as by providing for pumpingout of a catching container when the drying program has been terminated or shortened in consequence of responding of level-signalling equipment.

According to the present invention, there is provided a household laundry drier provided with a catching container arranged in a lower portion of the drier to catch condensate from condensing equipment in the drier, a pump operable to pump condensate out of the catching container, an electric motor to drive the pump, a collecting container arranged in an upper portion of the drier to collect condensate pumped out of the catching container and being withdrawable towards an operating side of the drier, overflow duct means to conduct overflow condensate from the collecting container back to the catching container, and control means comprising a level sensing switch operable in dependence on the level of condensate in the catching container, two alternately conductive motor control switches each electrically connected between the motor and a respective one of two alternately selectable terminals of the level sensing switch, a switching stage electrically connected to one of the terminals to so control the motor control switches that the control switch connected to that terminal is arranged to be non-conducting when the level of condensate in the catching container is below the level at which the level sensing switch operates, and a position sensing switch so electrically connected to the motor and the switching stage and operable in dependence on the position of the collecting con tainer as to complete a circuit for the motor when the collecting container is fully inserted and a circuit for the switching stage when the collecting container is withdrawn.

In a preferred embodiment, the drier comprises a collecting container, which is arranged at the top and withdrawable towards the drier operating side, for condensate from a catching container arranged below condensing equipment, the condensate being pumped up by means of a pump, driven by an electric motor, from the catching container at the bottom of the drier. The drier further comprises level-signalling equipment and a return duct to the catching container for condensate overflowing from the collecting container.The level-signalling equipment comprises a change-over switch, the output lines of which are connected with the pump motor on the one hand and with a switching stage on the other hand and which in one output line and in a cross-connection from the motor to the other output line has alternatively conducting switching paths interrupting the cross-connection when the catching container is empty. Also provided is an end position monitor which produces the current circuit for the pump motor when the collecting container is fully inserted and which includes a switch producing the current circuitforthe switching stage when the collecting container is withdrawn. In the case of response of the level-signalling equipment, the switching-off of the heating at first and the stopping of the entire program a certain time thereafter could be initiated as switching measure.Then, after the operator person has emptied and again inserted the collecting container, the pump would at first pump the condensate out of the catching container into the collecting container until the level-signalling equipment again supplies the one output line with voltage and the drying program would then be resumed exactly at the point at which it had been interrupted on the responding of the level-signalling equipment.

A possibility of initiating a similar switching measure in the prior art drier would be to switch over the condensate pump to continuous operation on responding of the level-signalling equipment, whereby a constant circulation of the excess condensate would take place between the collecting container and catching container. As soon as the operator would have emptied and again inserted the collecting container, the pumped-up condensate would be caught in the collecting container and no longer flow back through the return duct to the catching container. As a result, the level in the catching container would then lower and the levelsignalling equipment would switch back to the normal drying program.However, a measure of that kind would presuppose design of the condensate pump for 100% switching-on duration, because account must be taken of the fact that the operator may not be in the proximity of the drier when the level-signalling equipment responds and thus might not notice the fault indication. The pump would then run uninterruptedly for an indefinite time.

By contrast, in a drier embodying the present invention the pump can be designed for less than 100% switching-on duration, because it can run intermittently in normal operation and then be switched off in the event of a fault.

Preferably, the switching stage comprises a relay and the motor control switches comprise relay contacts. Such an arrangement may be particularly economical, but should electronic switching means become cheaper and more reliable,then use thereof for the switching stage can be made.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a laundry drier embodying the invention, from which the parts not essential for an understanding of the embodiment have been omitted; and Figure2 is a circuit diagram of control means of the drier.

Referring now to the drawings, there is shown in Figure 1 a laundry drier comprising a housing G which in its lower part contains a condensatecatching container KA, which is arranged underneath a condenser (not shown) for exhaust air to be dehumidified. A level-signalling device N, which can comprise, for example, a float with a double-armed lever and a change-over switch w connected thereto, is arranged partly in the catching container KA.

Connected to a lower outlet opening of the catching container KA is a condensate pump P, which can pump condensate collected in the catching container KA through a rising duct SL into a condensate collecting container KS. Since the condensate is caught in the container KA at a slower rate than the conveying rate of a pump conventionally used for this purpose, an intermittent pump operation can be employed.

The collecting container KS is inserted into a receiving space in the housing G and in its proper end position actuates an end position monitor Twith a switch t.

The receiving space also serves to catch condensate overflowing from the collecting container KS and is connected by a return duct RL with the catching container KA. Overflowing condensate can therefore be conducted back through the return duct to the catching container.

Insofar as condensate furthermore arising out of the condensing equipment is caught during the return of overflowed condensate, the level in the catching container KA rises until the level-signalling equipment adopts the position illustrated in dashed lines and finally switches over the switch w from 1-2 to 1-4.

In the circuit arrangement illustreated in Figure 1, the electrical equipment of the household laundry drier is supplied with voltage through two lines V1 and V2. The change-over switch w of the levelsignalling equipment N, which in normal operation connects the contacts 1 and 2 when the condensate has not yet overflowed, is connected to the line V1.

The output line Al of the level-signalling equipment leads to the pump motor M and can, in the part shown in dashed lines, include contacts of the program control device or of program-selecting equipment. The output line Al can also be connected to the remaining electrical equipment of the laundry drier.

The other output line A2 of the level-signalling equipment N is connected with a switching stage S, for example a miniature relay, and with a signal lamp K. The output lines Al and A2 are connected each with the other through a cross-connection Q.

Alternately conducting switching paths, namely the switches sl and s2, for example relay contacts, are so connected into the output line Al and the cross-connection Q that, when the level-signalling equipment does not respond, i.e. in the case of the catching container being empty, the output line Al is connected through to the pump motor M and the cross-connection is interrupted by the switch s2. The change-over switch t of the end position monitor T for the collecting container KS is present in the return lines from the motor M and from the switch stage S and switches the switch t over to the contacts 1 and 2 when the collecting container is in its proper end position and thereby connects the pump motor M to both voltage poles.

For a description of the function, it is assumed that the amount of laundry to be dried contains a quantity of water exceeding the capacity of the collecting container and of the catching container and that the operator does not empty the collecting container KS in time before overflowing.

The drying program at first runs normally so that condensate collected in the catching container can be steadily conducted away by means of the pump P into the collecting container KS. The circuit is in that case disposed in the illustrated rest state. In the case of condensate overflowing from the completely filled collecting container KS, the level in the catching container KA rises gradually and its levelsignalling equipment N now applies the switch w to the contacts 1 and 4. As a result, the voltage is switched from the output line Al to the output line A2. Immediately, the motor M stops and the signal lamp K is switched on. If so desired, an acoustic signalling device may be provided and arranged to be switched on at the same time as the signal lamp K.

Switching means, which at the instant of the responding of the level-signalling equipment N can influence the heating and - delayed - the program course equipment, should expediently also be connected to the output line Al so that these electrical parts can be taken out of operation on the switchingoff of the output line Al. Although the supply lines V1 and V2 remain at voltage, the program course of the laundry drier is stopped.

As soon as the operator has recognised the fault state and withdraws the collecting container KS from the receiving space, the switch t of the end position monitor T switches over to the contacts 1 and 4 and thereby applies the switching stage S to voltage, which at once maintains itself through its own switch s3. Moreover, the switches sl and s2 now change their positions so that the pump motor lies at voltage at one side through the cross-connection Q and the output line A2. As soon as the operator person has properly reinserted the collecting con tainer KS into the receiving space, the switch t again changes over to the contacts 1 and 2 so that the motor M again is subject to voltage at both poles and drives the pump P.Consequently, the condensate is transferred out of the catching container KA into the collecting container KS until the level-signalling equipment N switches the switch w back to the contacts 1 and 2. The signal lamp Kthen exting uishes and the switching stage S again becomes free of voltage so that its switches s1 and s3 return to the illustrated position. The motor M now receives voltage through the output line Al and conveys the remaining condensate in the catching container into the collecting container KS. The drying program, which was interrupted on the responding of the level-signalling equipment N, is now resumed at this point and continues to its conclusion.

The line V3 indicates that further switching means, other than those drawn here, of the remaining electrical equipment of the laundry drier must be further supplied with voltage after the responding of the level-signalling equipment N.

In the known laundry drier, the withdrawal of the collecting container from the receiving space during the conveying of the pump would lead to an issuing of a proportion of the condensate out of the receiving space, because in constraint of arranging the feed opening in the collecting container as widely as possible at the operating side, in order that the risk of the spillage or escape of collected condensate is as small as possible during withdrawal of the collecting container, leads to the mouth of the rising duct also being arranged a long way towards the operating side. If the pump is just in operation, a not inappreciable proportion of conveyed condensate can then issue from the receiving space cavity. In the case of the described embodiment of the present invention, however, this risk does not arise, because the withdrawal of the collecting container KS immediately has the consequence of the switching-off the pump through the end position monitor T.

Claims

1. A household laundry drier provided with a catching container arranged in a lower portion of the drier to catch condensate from condensing equipment in the drier, a pump operable to pump condensate out of the catching container, an electric motor to drive the pump, a collecting container arranged in an upper portion of the drier to collect condensate pumped out of the catching container and being withdrawable towards an operating side of the drier, overflow duct means to conduct overflow condensate from the collecting container back to the catching container, and control means comprising a level sensing switch operable in depend ence on the level of condensate in the catching container, two alternately conductive motor control switches each electrically connected between the motor and a respective one of two alternately selectable terminals of the level sensing switch, a switching stage electrically connected to one of the terminals to so control the motor control switches that the control switch connected to that terminal is arranged to be non-conducting when the level of condensate is the catching container is below the level at which the level sensing switch operates, and a position sensing switch so electrically connected to the motor and the switching stage and operable in dependence on the position of the collecting container so as to complete a circuit for the motor when the collecting container is fully inserted and a circuit for the switching stage when the collecting container is withdrawn.

2. A drier as claimed in claim 1, wherein the switching stage comprises a relay and the motor control switches comprise relay contacts.

3. A household laundry drier substantially as hereinbefore described with reference to the accompanying drawings.