EP0776450B1 - Circuit for the operation of an electrically actuated magnet valve - Google Patents

Description

The invention relates to a circuit arrangement for operation an electrically controllable solenoid valve with at least one valve actuator that can be brought into two working positions, by adjusting each one to the respective working position Corresponding one charged with a flow medium Flow path is selectable.

Circuit arrangements according to the preamble of the claim 1 are for example in refrigeration units with several compartments different temperature to control from there to Upcoming, bistable solenoid valves in use, based on which of a compressor in a refrigeration cycle generated refrigerant flow to the evaporators in the compartments different temperature depending on the cooling demand becomes. For this purpose, the valve actuator of the bistable Solenoid valve according to the refrigeration requirement from the storage compartments the refrigerator in one or the other working position emotional. This happens by the electromagnets on the valve actuator force exerted as a result of which the valve actuator in its locking position is accelerated, with the Closing process generates a clearly audible noise becomes. In the past, this is due to the valve actuator arranged soundproofing measures in the form of that Closing the nozzle-like feed openings Plastic parts taken into account. For such plastic parts is, however, around these at the nozzle-like feed openings not wear out prematurely, a relatively high shore hardness too choose what inevitably turn a not insignificant Deterioration of noise insulation.

The invention has for its object to propose measures, which in a simple way a quiet Enable operation of an electrically controllable solenoid valve.

This object is achieved according to the invention in that Circuit arrangement has means by which the adjustment the valve actuator in the other working position following an application of at least the Solenoid valve formed section of the flow path flow medium present predominantly in liquid fractions he follows.

With the solution according to the invention, there is a useful life of the electrically controllable solenoid valve constant, due to the liquid flow medium generated speed and associated noise reduction generated for the moving valve actuator, because the Noise reduction of material properties that may change of commonly used for noise insulation Materials such as the aging process for plastics, is independent. Furthermore, the degree of damping for the valve actuator in a simple manner by its geometric Design can be influenced.

According to a further preferred embodiment of the object the invention provides that the means for Acting on the section formed by the solenoid valve the flow path with liquid flow medium by a time delay in the adjustment of the valve actuator regarding an activation of the flow medium driving means is achieved.

Such a solution is particularly simple and Way ensured without additional sensor effort that the section of the flow path formed by the solenoid valve is charged with liquid flow medium.

A time delay is particularly easy to generate, if after a further advantageous embodiment of the object the invention provides that the temporal Substantially delaying means is formed electromechanically trained timer. In addition Such a timer is characterized by its robust Construction from.

According to an alternative embodiment of the object the invention provides that the time delay effective means by one of electronic components composite timer is formed.

With such a solution, the magnitude of the time delay can can also be varied easily afterwards. In addition, such a timer is extremely inexpensive realizable.

According to a further preferred embodiment of the object the invention provides that the temporal Delay is in the range between 30 s and 90 s.

A time delay has proven to be particularly applicable result if according to a next advantageous embodiment the subject of the invention is provided that the temporal Delay is 60 s.

According to a further particularly advantageous embodiment of the The object of the invention is that for driving of the flow medium serving as a refrigerant compressor is trained.

Fig. 1

ein Zweitemperaturen-Kühlgerät bei geöffneten Türen mit einem Kühl fach und einem Gefrierfach, deren Temperaturen durch eine elektronische Regeleinrichtung gesteuert sind,

Fig. 2

einen Ausschnitt der elektronischen Regeleinrichtung mit einer elektronischen Schaltungsanordnung zur Ansteuerung eines den Kältemittelfluß zum Gefrierfach bzw. Kühlfach steuernden Elektromagnetventils.

The invention is explained in the following description using the example of a multi-temperature cooling device shown in simplified form in the accompanying drawing. Show it:

Fig. 1

a two-temperature refrigerator with open doors with a refrigerator compartment and a freezer compartment, the temperatures of which are controlled by an electronic control device,

Fig. 2

a section of the electronic control device with an electronic circuit arrangement for controlling a solenoid valve controlling the flow of refrigerant to the freezer or refrigerator compartment.

1 shows a fridge-freezer combination 10, whose heat-insulating housing 11 two by one heat-insulating partition 12 thermally separated, arranged vertically one above the other and with separate Doors 13 and 14 have lockable storage compartments. The higher lying lockable with the door 13 Storage compartment designed as a cooling compartment 15, which with vertical Distances arranged one above the other, for parking of refrigerated serving stands 16 is equipped. The others arranged below the cooling compartment 15, by the latter storage compartment separated by the heat-insulating partition 12 is designed as a freezer compartment 17, which for Frozen food can be pulled out like a drawer 18 has.

Both the refrigerator compartment 15 and the freezer compartment 17 is for Maintaining its intended storage room temperature equipped with evaporators, not shown, which integrated in a refrigeration circuit, also not shown are within which a the evaporator with liquid Refrigerant supplying compressor is arranged, which is operated intermittently, the inputs and Shutdown phases of the compressor from those in the storage compartments prevailing temperatures are dependent. These will detected by temperature sensors, not shown, and in one belonging to an electronic control device Evaluation logic 19 on the one hand in temperature display elements displayable values and on the other hand to a further processable in a circuit arrangement 30 Digital signal "A" processed (see Fig. 2).

As can be seen in particular from FIG. 2, the digital signal "A" present on the output side at the evaluation logic 19 represents the input signal for the circuit arrangement 30, which is equipped on the input side with two RC elements which serve to achieve different time periods. These are formed by two ohmic resistors 31 and 32 arranged in parallel with different resistance values and a common capacitor 33 connected in series, the resistor 32 equipped with the lower resistance value being preceded by a diode 34 which, with its cathode connection to the Resistor 32 is connected so that it takes place via the charging process of the capacitor 33 via the higher-resistance resistor 31. The voltage potential generated by the charging process on the capacitor 33 is connected to the merged inputs of a NAND gate 35, the output signal of which is fed to the base of a PNP transistor 36, the emitter connection of which is connected to a DC voltage supply "U _B ", while its collector connection is connected via one of the Collector current-limiting ohmic resistor 37 is connected to ground potential. Between the collector connection of the PNP transistor 36 and the ohmic resistor 37, the gate connection for tapping the ignition current of a triac 38 is arranged, with its second main electrode connection a monostable coupled to the line pole "L" of a 230 volt AC voltage , two flow paths switching solenoid valve 39 is connected. The other main electrode connection of the triac 38 is connected to the zero pole "N" of the AC voltage supply, which at the same time also forms the ground connection for this main electrode of the triac 38.

One for the cooling compartment 15 due to the increased therein Storage temperature existing cooling demand is at the exit the evaluation logic 19 by a logic one for the output signal "A" indicates which one is the activation of the refrigerant compressor and on the other hand one Switching process of the monostable solenoid valve 39 from its Rest position for changing the flow path for the Refrigerant to the evaporator of the refrigerator compartment 15 means. Here is the switching process of the electrically controllable Solenoid valve 39 through from the resistor 31 and the RC element formed the capacitor 33 with respect to the switch-on process of the compressor delayed because the logical "one" at the output of the evaluation logic 19 only after the completion of the charging of the capacitor 33 to the merged inputs of the NAND gate 35 is present and generates a logical "zero" at its output, which the base of the PNP transistor serving as an electronic switch 36 is supplied, whereby this in conductive State is offset. The by the line condition of the PNP transistor 36 between its emitter and its collector flowing current serves as the ignition current for the triac 38, which creates the circuit for the monostable solenoid valve 39 is closed, so that the desired change in position of its valve actuator serving as the solenoid to redirect the refrigerant to the Evaporator of the refrigerator compartment 15 takes place.

By connecting the NAND gate 35 on the input side with that formed from the resistor 31 and the capacitor 33 RC element is delayed, as already described, the control of the solenoid valve 39 compared to the control of the compressor in time, this in itself on the basis of the output signal output by the evaluation logic 19 "A" for a refrigeration request for the refrigerator compartment 15 should take place simultaneously. Because of the temporal Delay between start-up of the compressor and the change in the flow path for the refrigerant the solenoid valve 39 ensures that the latter with refrigerant present in the liquid phase is flowed through, so that the switching movement of the Change of direction for the valve actuator causing the flow liquid-damped and therefore largely takes place silently without additional damping measures. As for the magnitude of the delay times useful times are between 30 s and 90 s already shown good results, with a delay time of 60 s proved to be favorable.

It is also possible instead of after the Compressor activation of the solenoid valve 39 to ensure fluid damping for the valve actuator a liquid sensor to monitor the Provide liquid level in the solenoid valve 39.

Has the storage temperature in the refrigerator compartment 15 its needs Setpoint is reached, this is done via temperature sensors the evaluation logic 19 signals, whereupon this signals a signal to shut down the compressor and a logical Outputs "zero" as output signal "A". This lies as a switching signal for the solenoid valve 39 around the discharge time of capacitor 33 is delayed at the input of the NAND gate 35, due to the resistance 31 much lower resistance value for the resistance 32 the switching process of the solenoid valve 39 in its the Flow path to the freezer compartment evaporator, in the idle position occurs almost simultaneously with the stop of the compressor. Due to the slight delay, for which has already proven to be favorable for a time of 50 ms, it is ensured that at least the through the solenoid valve 39 predetermined flow path of the refrigeration circuit is still charged with liquid refrigerant and thus the switching process of the valve actuator is liquid-damped and thus takes place almost silently.

In the event that 17 refrigeration demand is reported for the freezer is the output signal "A" of the evaluation logic 19 logically "zero", whereby a logical at the NAND gate 35 "One" is present and thus transistor 38 blocks, so that the triac 38 is inactive and thus the solenoid valve 39 is de-energized is.

Instead of the discrete electronic in the exemplary embodiment Components of circuit arrangement 30 it is also conceivable whose and the evaluation logic 19 underlying function by an appropriately programmed Microprocessor replicate, so that the time delayed start-up of the solenoid valve 39 with respect the compressor through an appropriate software program could be accomplished.

It is understood that the invention also applies to a circuit a bistable solenoid valve with this circuit then to be provided valve-specific wiring change is applicable.

Claims (8)

1. Switching arrangement for operation of an electrically controllable magnet valve with a valve setting element which is bringable at least into two working settings and through the adjusting of which a respective flow path, which corresponds with the respective working setting and is acted on by a flow medium, is selectable, characterised thereby that the switching arrangement comprises means by which the adjusting of the valve setting element into the respective other working setting is carried out in conjunction with a loading at least of that portion of the flow path, which is formed by the magnet valve (39), with a flow medium present predominantly in liquid components.
2. Switching arrangement according to claim 1, characterised thereby that the means for loading of that portion of the flow path, which is formed by the magnet valve (39), with liquid flow medium is effected by a time delay of the adjusting of the valve setting element with respect to an activation of a means driving the flow medium.
3. Switching arrangement according to claim 2, characterised thereby that the means effecting the time delay is formed by a time element constructed substantially electromechanically.
4. Switching arrangement according to claim 2, characterised thereby that the means effecting the time delay is formed by a time element (31, 33) assembled from electronic components (31, 33).
5. Switching arrangement according to one of claims 2 to 4, characterised thereby that the time delay lies in the region between 30 seconds and 90 seconds.
6. Switching arrangement according to one of claims 2 to 5, characterised thereby that the time delay amounts to 60 seconds.
7. Switching arrangement according to claim 2, characterised thereby that the means serving for driving the flow medium is constructed as a coolant compressor.
8. Cooling appliance, especially refrigerator or freezer or refrigerator and freezer combination, characterised by a switching arrangement (30) according to one of claims 1 to 7.

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