JPS6346528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a circuit that operates a switch at a predetermined time and then returns to the original state by receiving a control signal from the outside; This type of time switch is equipped with a circuit for returning to its original state, and is related to a repeatable time switch used for defrosting control of refrigeration equipment such as a freezer or a refrigerating case.

The following methods are commonly used in defrosting control of refrigeration equipment.

That is, the time switch stops the refrigerator and the cold air agitation fan at predetermined time intervals, energizes the defrost heater, and melts the frost by the heat generated by the defrost heater. As defrosting progresses and the frost melts away, a defrost detection thermostat installed near the evaporator to which the frost adheres detects the temperature change and operates. The thermostat energizes the relay to cut off the power to the defrosting heater and restart the refrigerator and cold air stirring fan.

According to the defrosting control means having the above configuration, when the refrigerator and the cold air stirring fan are restarted, there is residual heat near the evaporator, and this residual heat is circulated by the cold air stirring fan into, for example, the freezing case. There is a problem in that the temperature rises and the air pressure inside the show case rises, causing damage to the door or window.

One way to solve this problem is to restart the cold air stirring fan a little later (by about a few minutes) than to restart the refrigerator. The so-called Juan Delay is being considered. Conventionally, the control means for this fan relay was different from the 24-hour time switch.
A short-time timer that is started by a signal from a defrosting detection thermostat is provided, and a means for performing a fan delay using this short-time timer has been taken. but,
Since this method converts the detected temperature near the evaporator into an element called time, sufficient effect cannot be expected unless the time setting is appropriate. Furthermore, a new device called a timer is required, making the control device expensive. Become.

This invention was made in view of the above-mentioned circumstances, and performs fan delay by directly detecting the temperature without using new equipment such as a timer or converting the temperature near the evaporator into a time element. The purpose of this invention is to provide a time switch that can achieve this.

The configuration and operation of an embodiment of the time switch of the present invention will be described below using an example in which an embodiment of the time switch of the present invention is used for defrosting control of refrigeration equipment.

In the drawing, T is a timer, which is composed of a synchronous motor M and a changeover switch _S1 , and the changeover switch _S1 is operated by the synchronous motor M to switch to the state indicated by the broken line at a predetermined time for a predetermined period of time (for example, 15 minutes). It is set so that it returns to the state shown by the solid line after the _S2 is a changeover switch operated by a defrost detection thermostat installed near the evaporator, and is normally on the low temperature side as shown by the solid line, but if the temperature near the evaporator rises after defrosting, As shown by the broken line, it is switched to the high temperature side, and when the temperature near the evaporator falls, it automatically returns to the low temperature side. X is the 1st and 2nd switch
This is a relay having X ₁ , X ₂ and a service switch X ₃ , where each switch X ₁ , X ₂ , X ₃ is always in a solid line state, and operates in a broken line state when relay X is energized. H is the defrosting heater, MC is the compressor drive electric motor (hereinafter simply referred to as the compressor),
MF is an electric motor for driving a cold air stirring fan (hereinafter referred to as cold air stirring fan). 1S, 2S, C ₀ , C ₁ ,
C ₂ , 3L, 2L, and 1L are terminals, respectively.
S is a power source. The configuration of the time switch according to the present invention is shown surrounded by a dashed line.

Next, the operation of the time switch in the above configuration will be explained. First, during refrigeration operation, turn on the selector switch.
S ₁ , S ₂ and switches X ₁ , X ₂ , X ₃ of relay X are all in the state shown by solid lines. That is, compressor MC
The cold air stirring fan MF is energized, and the defrosting heater H is not energized. Note that the synchronous motor M is always energized. In this state, at a predetermined time, the changeover switch _S1 is switched to the state shown by the broken line, and power is started to the defrosting heater H, and at the same time power to the compressor MC and cold air stirring fan MF is cut off. It will be done. When the defrosting heater H starts to be energized, the defrosting heater H generates heat, and the heat is transmitted to the evaporator and melts the frost attached to the evaporator and its vicinity. When the temperature near the evaporator rises rapidly as the frost melts away, the defrost detection thermostat switches the changeover switch _S2 to the state indicated by the broken line. As a result of this switching, relay X is energized and its contacts X ₁ , X ₂ , X ₃ all operate to the state shown by the dashed lines. That is, the power to the defrosting heater H is cut off,
Compressor MC restarts. However, the cold air stirring fan MF has switch _S2 set to the high temperature side (dotted line).
It won't start because it's on. Next, when the evaporator and its vicinity are gradually cooled down to a predetermined temperature by restarting the compressor MC, the defrost detection thermostat returns the switch _S2 to the original low temperature side shown by the solid line. . At this time _{, relay X is} self _- held via _switch Retain state. Therefore, when the selector switch _S2 returns to the low temperature side (solid line state) as shown above,
The cold air stirring fan MF is energized via the changeover switches S ₁ , S ₂ and the switch X ₂ . Finally, the changeover switch _S1 returns to the state shown by the solid line after a predetermined period of time (for example, 15 minutes) has elapsed. Due to this return, relay
is deenergized, and switches X ₁ , X ₂ , X ₃ of relay
return to the states shown by the _solid lines, so the compressor
The MC, the cold air stirring fan MF are energized, and the defrosting heater H is kept de-energized, resulting in normal refrigeration operation.

By repeating the above operations at regular intervals, defrosting operations are performed periodically.

As mentioned above, the time switch of this invention is as follows.
Since it is configured in combination with a changeover switch operated by a defrost detection thermostat, there is no need to use a special timer, and the defrost state is directly detected as a temperature without converting it into a time element, making fan delay easy. This can be achieved quickly, reliably, and inexpensively.

[Brief explanation of the drawing]

The drawing is a configuration diagram showing an embodiment of the present invention. In the figure, T is a timer consisting of a synchronous motor M and a changeover switch _S1 , _S2 is a changeover switch for the detection element,
X is a relay, X ₁ is a first switch, X ₂ is a second switch, and X ₃ is a normally open switch.

Claims (1)

[Claims] 1 Compressor MC, cold air stirring fan MF, and defrosting heater H, each of which has one end connected to one of the power sources,
A first normally closed contact S 1 a connected to the other end of the compressor MC and a first common contact S ₁ a connected to the other end of the power source and switched and connected to the first normally open contact S ₁ b at predetermined time intervals. A changeover switch S ₁ has a contact S ₁ c, a second normally closed contact X ₁ a connected to the other end of the defrosting heater H, and a second normally closed contact S 1 b connected to the first normally open contact S ₁ b. a first switch X ₁ having a second common contact X _{1 c} switched connected to a normally open contact X 1 b, said second normally open contact X ₁ b;
The third normally open contact S ₂ b on the high temperature side is connected to the high temperature side, and the third normally closed contact S ₂ on the low temperature side is connected to the second common contact X ₁ c and connected to the thermostat installed near the evaporator. a second changeover switch S ₂ having a third common contact S ₂ c connected to said a, a fourth normally closed contact X ₂ a connected to said first normally closed contact S ₁ a and said stirring a second switch having a fourth common contact X 2 c connected to _{the fan MF and switched to a fourth normally open contact S 2 b connected to the third normally closed contact S 2 a on} the low temperature side; X ₂ , a normally open switch with one end connected to the other of the above power sources and the other end connected to the above fourth normally closed contact X ₂ a
X ₃ , and one end is connected to one of the above power sources and the other end is connected to the above second normally open contact X ₁ b, and when energized, the above first,
Equipped with a relay X that switches on and off the second switches X ₁ and X ₂ and _a normally open switch
The MC and cold air stirring fan MF are driven via the first and fourth normally closed contacts S ₁ a and X ₂ a, and when defrosting starts, the defrosting heater is switched on by switching the first changeover switch S _1. H is energized through the second normally closed contact _X1a , and the compressor MC and cold air stirring fan MF are stopped, and the thermostat causes the second changeover switch _S2 to switch to the third normally open state. When the contact S ₂ b is switched, the first switch X ₁ is switched by the energization of the relay X, and the defrosting heater H is switched on.
is de-energized and the compressor MC is restarted via the normally open switch _X3 , and then the thermostat switches the second changeover switch _S2 to the third normally closed contact _S2a . When the cold air stirring fan MF is replaced, the normally open contact X ₂ b of the second switch X ₂
A time switch characterized in that it is configured to be restarted via.