JPH0422070Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a heat pump type air conditioner capable of cooling and heating operations.

(Prior art) Conventionally, a refrigeration cycle used in an air conditioner consists of a compressor, a four-way switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, etc. connected in sequence to form a heat pump refrigeration cycle. By switching the refrigerant flow direction using a four-way switching valve, cooling or heating operation can be performed freely.

By the way, for such an air conditioner,
It is equipped with a high-pressure switch that operates when the pressure on the high-pressure side of the refrigeration cycle rises abnormally, and the operation of the high-pressure switch is stopped to protect the refrigeration cycle. In this case, a manual reset type high pressure switch is used, so that even if the pressure on the high pressure side drops after the operation has stopped, operation cannot be resumed unless the high pressure switch is manually reset. This is to prevent inconveniences such as the compressor being adversely affected by the compressor.

(Problem that the invention aims to solve) Conventionally, air conditioners like this have been designed mainly for cooling, so during normal times the pressure on the high pressure side rises above the value set on the high pressure switch. Manual reset type high pressure switches were used because it was thought that if the high pressure switch operated, it meant that some kind of refrigeration cycle component was abnormal.

In other words, if the high-pressure switch operates, it is due to an abnormality in the refrigeration cycle parts, such as a disconnection in the outdoor fan or a foreign object clogging the piping during the refrigeration cycle. Inspect the parts,
After confirming that there was no abnormality, the high pressure switch was set again and the operation was resumed.

However, in recent years, the reliability of each refrigeration cycle component has improved, and in fact, high-pressure switch operation due to abnormality in refrigeration cycle components has almost disappeared.In contrast, indoor heat exchangers have become significantly smaller due to the miniaturization of air conditioners. Due to factors such as the increasing number of people using air conditioning systems and heating operations even in early spring, when air with a relatively high load temperature is drawn into a compact indoor heat exchanger and heated, it causes damage to refrigeration cycle parts. A new problem has arisen in which the high pressure switch is activated due to overload even though no abnormality has occurred.

In the case of such an overload during heating, the high pressure switch only needs to be temporarily stopped to protect the compressor, and there is no need for inspection after the high pressure switch is activated. However, in the past, as in the case of an abnormality in the refrigeration cycle, it was necessary to reset the manual reset type high pressure switch and perform the operation, which was extremely inconvenient.

[Summary of the invention] (Means for solving the problem) The present invention is an automatic reset type high pressure switch that operates when the high pressure side pressure of the refrigeration cycle exceeds a set value and automatically returns when it falls below the set value. and a stop control means for cutting off power to the drive motor of the compressor that is operated in conjunction with the operation of the high pressure switch, and a self-holding means for self-maintaining the stop control state regardless of the return of the high pressure switch; A timer is provided which is operated in conjunction with the operation of the high pressure switch during heating operation and releases the operation of the self-holding means after a predetermined period of time.

(Function) When the automatic reset type high pressure switch is activated during heating operation of the air conditioner, the compressor operation is immediately stopped, the compressor drive motor is kept stopped for a certain period of time, and after a certain period of time it is stopped. When the high pressure switch is restored, the compressor drive motor is automatically operated to restart operation.

(Example) An example of this invention will be described below with reference to the drawings.

In FIG. 1, a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, a pressure reducing device such as a capillary tube 4, and an indoor heat exchanger 5 are connected in sequence to form a heat pump type refrigeration cycle.

Thus, during cooling operation, the refrigerant flows in the direction of the solid arrow shown in the figure, and during heating operation, the four-way switching valve 2 is activated, so that the refrigerant flows in the direction of the solid arrow shown in the figure. There is. Further, an outdoor blower 6 for circulating outdoor air is provided opposite to the outdoor heat exchanger 3. The indoor heat exchanger 5 is provided with an indoor blower 7 facing each other for circulating indoor air.

FIG. 2 shows the control circuit. Reference numeral 10 denotes an operation changeover switch, the contacts of which are indicated by diagonal lines in the figure, are made conductive depending on the set position. That is, when set to "heating", the a-b contacts, c-d contacts and g-h
The contacts are each conductive. Thus, the blower motor 7M of the indoor blower 7 is connected to the single-phase AC power source (100V) 20 via the a-b contacts and the c-d contacts of the changeover switch 10. The power source 20 also includes the e-f contacts and g-h contacts of the changeover switch 10, the room temperature thermoswitch 21, the normally closed side of the changeover contact 24a of the relay 24 constituting self-holding means, which will be described later, and the high voltage switch 2.
2. Normally closed time-limited operation contact 2 of timer 25, which will be described later.
5a, a normally closed contact 31a of an overload relay 31, which will be described later, and a-b contacts of a changeover switch 10 are connected to a compressor electromagnetic switch 23, which serves as a stop control means. A relay 2 is connected to the normally closed side of the switching contact 24a and the series circuit of the high voltage switch 22.
4 are connected in parallel. Further, a timer 25 is connected to the power supply 20 via the e-f contacts, g-h contacts of the changeover switch 10, the room temperature thermoswitch 21, the normally open side of the changeover contact 24a, and the ab contacts of the changeover switch 10. be done. In addition, the power supply 20 includes the e-f contact, the g-h contact of the changeover switch 10, the room temperature thermoswitch 21, and the changeover switch 1.
The blower motor 6M of the outdoor blower 6 is connected through the a-b contact point of 0. Further, the electromagnetic coil 2c of the four-way switching valve 2 is connected to the power source 20 via the gh contact and the a-b contact of the changeover switch 10. Here, the indoor temperature thermoswitch 21 closes between the movable terminal 21c and the fixed terminal 21a when the indoor temperature is above a predetermined value, and closes between the movable terminal 21c and the fixed terminal 21b when the indoor temperature is below the predetermined value. It is something that closes. The high-pressure switch 22 responds to the high-pressure side pressure of the heat pump type refrigeration cycle, and is activated (opened) when the high-pressure side pressure increases abnormally and exceeds a predetermined value, and returns to the closed state (closed) when the high-pressure side pressure rises abnormally and exceeds a predetermined value. The purpose is to maintain the current state of development. On the other hand, 30 is a three-phase AC power supply (200V), and this power supply 30 is connected to the electromagnetic switch 2.
3 normally open contact 23a and overload relay 3
A drive motor for the compressor 1, so-called compressor motor 1M, is connected through the compressor 1.

Next, the operation in the above configuration will be explained.

Now, when the changeover switch 10 is set to "heating", the operation of the indoor blower 7 is started and the four-way switching valve 2 is activated. Moreover, at this time, if the indoor temperature is below a predetermined value, the electromagnetic switch 23 is activated and the operation of the compressor 1 is started.
Operation of the outdoor blower 6 is started. In other words, heating operation is performed.

In this manner, when the heating operation is being performed, as the outdoor temperature rises, the high-pressure side pressure of the refrigeration cycle increases accordingly. When the high pressure side pressure rises and exceeds a preset value, the high pressure switch 22 opens and the relay 24 is connected to the energizing path for the electromagnetic switch 23.
is injected. In this case, the impedance of the relay 24 is set to a much larger value than the impedance of the electromagnetic switch 23, so that the relay 24 is activated, while the operating state of the electromagnetic switch 23 is released. Then, when the operating state of the electromagnetic switch 23 is released, the operation of the compressor 1 is stopped, and the refrigeration cycle is protected. Further, in conjunction with the operation of the relay 24, the timer 25 is activated. At this time, when the high pressure side pressure decreases due to the operation of the compressor 1 being stopped and becomes below a preset value, the high pressure switch 22 will return (close), but the contact 24a of the relay 24 will be closed. Therefore, the operation of the compressor 1 continues to be stopped, and
The operating state of the relay 24 is self-maintained by the contact 24a. Therefore, the compressor 1 continues to be stopped regardless of the return of the high pressure switch 22, so that the operation does not start and stop unnecessarily, and the compressor 1 is not adversely affected.

When a predetermined period of time has elapsed since the timer 25 was activated, the time-limited operation contact 25a of the timer 25 is opened and the relay 24 is deactivated. Then, when the time-limited operation contact 25a returns (closes), the electromagnetic switch 23 is activated and the operation of the compressor 1 is restarted. In this case, the fixed time until the time-limited operation contact 25a opens, that is, the time from when the operation of the compressor 1 is stopped to when it is restarted, is a sufficient time that does not adversely affect the compressor 1. .

Therefore, when the outdoor temperature rises or the pressure on the high pressure side of the refrigeration cycle abnormally increases during heating operation, the refrigeration cycle can be protected by immediately stopping the operation. Furthermore, since operation is automatically restarted after the operation has been stopped for a certain period of time, manual operation by the user as in the conventional case is not required, which is very convenient. Moreover,
In this case, sufficient time is secured from when the operation is stopped until it is restarted, so that the compressor is not adversely affected.

It should be noted that this invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without changing the gist.

FIG. 3 shows a first modification of the control circuit. In this case, the same parts as in FIG. 2 are given the same reference numerals. As shown in FIG. 3, during heating or cooling operation, when the high pressure increases abnormally and exceeds a set value, the high pressure switch 40 is activated (closed), and the relay 41 and timer 25 are activated. When the relay 41 is activated, the contact 41a is closed to form a holding circuit for the relay 41 and the timer 25, and the contact 41b is opened to release the operating state of the electromagnetic switch 23, and the compressor 1 operation stops. At this time,
Even if the high-pressure switch 40 is restored (opened), the relay 41 and the timer 25 continue to be in operation, and the compressor 1 continues to be stopped. When a predetermined period of time has elapsed since the compressor 1 stopped operating, the time-limited operation contact 25a opens and the relay 41
The operating state of is released. When the time-limited operation contact 25a returns, the operation of the compressor 1 is restarted.

FIG. 4 shows a second modification of the control circuit. In this case as well, the same parts as in FIG. 2 are given the same reference numerals. However, in Fig. 4, the operation during heating operation is similar to that in Fig. 2, but
During cooling operation, even if the high pressure switch 22 is opened, the relay 24 is activated and the timer 2 is activated.
5 does not operate, so that the compressor 1 is continuously stopped due to the operation of the relay 24. In this case, the cooling operation can be restarted by setting the changeover switch 10 once to "stop" and then to "cooling" again.

FIG. 5 shows a third modification of the control circuit. In this case, the same parts as in FIGS. 2 and 3 are given the same reference numerals. Therefore, in FIG. 5, during heating operation, the operation is the same as in FIG. Therefore, the compressor 1 continues to be stopped due to the operation of the relay 41. In this case, the cooling operation can be restarted by setting the changeover switch 10 once to "stop" and then to "cooling" again.

[Effect of the invention] As mentioned above, according to this invention, the compressor,
In an air conditioner equipped with a heat pump type refrigeration cycle that sequentially communicates a four-way switching valve, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger, the system activates when the high pressure side pressure of this refrigeration cycle exceeds a set value. An automatic return type high pressure switch that automatically returns when the voltage falls below a set value, a stop control means that cuts off power to the drive motor of the compressor that is operated in conjunction with the operation of the high pressure switch, and stop control thereof. The present invention is equipped with a self-holding means that maintains the state regardless of the return of the high-pressure switch, and a timer that is operated in conjunction with the operation of the high-pressure switch during heating operation and releases the operation of the self-holding means after a predetermined period of time. , during heating operation, it is possible to immediately stop operation when high pressure rises abnormally, and with a simple configuration, operation can be restarted automatically without adversely affecting the compressor etc., which has become popular in recent years. It is possible to provide a highly practical air conditioner that can eliminate the adverse effects of downsizing of air conditioners.

[Brief explanation of drawings]

The drawing shows one embodiment of this invention.
The figure is a block diagram schematically showing a heat pump type refrigeration cycle, Figure 2 is a control circuit block diagram, Figures 3 and 4 are
FIG. 5 and FIG. 5 each show a modification of FIG. 2. In the figure, 1 is a compressor, 22 is a high pressure switch, 23
2 is an electromagnetic switch (stop control means), 24 is a relay (self-holding means), and 25 is a timer.

Claims (1)

[Scope of utility model registration request] In an air conditioner equipped with a heat pump refrigeration cycle in which a compressor, a four-way switching valve, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger, etc. are connected in sequence, the high-pressure side pressure of this refrigeration cycle exceeds the set value. an automatic return type high pressure switch that is activated when the voltage drops below a set value and automatically reset when the voltage falls below a set value; a stop control means that cuts off power to the drive motor of the compressor that is operated in conjunction with the operation of the high pressure switch; a self-holding means for self-maintaining the stop control state regardless of the return of the high-pressure switch; and a timer for deactivating the self-holding means after a predetermined period of time that is operated in conjunction with the operation of the high-pressure switch during heating operation. An air conditioner characterized by comprising: