JPH04222371A - Protecting device for refrigerating equipment - Google Patents

Abstract

PURPOSE:To discriminate whether abnormal stopping is effected by a high- pressure protecting switch or a low-pressure protecting switch, which are connected in series to the protecting circuit of a refrigerating equipment. CONSTITUTION:The protecting circuit 2 of a refrigerating equipment is provided with a stopping device 3, in which the normally closed contact 63H of a high- pressure protecting switch HPS and the normally closed contact 63L of a low pressure protecting switch LPS are connected in series to the protecting circuit 2 and stopping the refrigerating equipment abnormally by the interception of the flow of current through the protecting circuit 2. When a predetermined period of time, corresponding to intermediate length of returning times of respective protecting switches HPS, LPS, is elapsed after the abnormal stopping dew to the operation of a stopping device 3, the condition of current flow through the protecting circuit 2 is discriminated by a discriminating means 51 whereby it is discriminated which switch between protecting switches HPS, LPS is operated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a protection device for a refrigeration system that abnormally stops the refrigeration system in response to an excessive rise in pressure on the high pressure side or an excessive drop in pressure on the low pressure side.

0002

[Prior Art] Conventionally, for example, Utility Model Publication No. 58-3358
As disclosed in Publication No. 1, in an electric circuit in which two normally closed contacts are connected in series to form a series circuit, a push button-shaped display body containing an electromagnetic coil is installed between the terminals of each normally closed contact. Each is provided so that when the normally open contact opens and current flows through the electromagnetic coil, the display body protrudes.
It is a known technique to identify which of the contacts is open based on the protruding and retracting state of the display body when power is cut off in a series circuit.

0003

[Problems to be Solved by the Invention] By the way, in a protection device for protecting equipment such as a compressor of a refrigeration system, a high-pressure protection switch and a By interposing a low-voltage protection switch in the protection circuit, and further providing a stop device that abnormally stops the refrigeration equipment in response to the interruption of power supply to the protection circuit, and activating the stop device in response to the opening operation of each of the above protection switches. ,
We are trying to protect equipment such as compressors. Normally, such high-voltage and low-voltage protection switches are connected in parallel with each other in a protection circuit together with a stop device, but there are cases where they must be connected in series for reasons such as control. In such a case, the processes to be taken are different when the high voltage protection switch is activated and when the low voltage switch is activated, so it is necessary to identify which one activated, but since they are connected in series, it is difficult to identify which one is activated. The problem arises that it becomes difficult. Therefore, it is conceivable to use the above-mentioned conventional device to detect which of the protection switches has been activated, but providing a separate display with such a special structure would increase costs. Become.

[0004] The present invention has been made in view of the above-mentioned problems, and its object is to check the connection state of the protection circuit when the equipment stops abnormally due to the high voltage protection switch or the low voltage protection switch connected in series to the protection circuit. By taking a means to detect which protection switch has been activated, it is possible to identify the activation of each protection switch with a simple circuit configuration and without the need for special equipment for identification. be.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the first solution of the present invention is to provide a high-pressure protection switch and a low-pressure protection switch among the above-mentioned protection switches. The object of the present invention is to provide a means for displaying which protection switch has been activated based on the energization state of the protection circuit at a predetermined time.

Specifically, the measures taken by the invention of claim 1 are as follows:
As shown in Figure 1, there is a high-pressure protection switch (HPS) that opens due to an excessive rise in pressure on the high pressure side of the refrigerant circuit of a refrigeration system and then returns in response to a decrease in pressure. A low pressure protection switch (LPS) that resets in response to a rise in rear pressure, and each of the above protection switches (HPS)
, (LPS) normally closed contacts (63H) and (63L) are connected in series, and a stop device (3) that abnormally stops the refrigeration equipment in response to the interruption of power supply to the protection circuit (2).
) is applicable to refrigeration equipment protection devices.

[0007] Then, when a predetermined time period has elapsed which is longer than the recovery time of the low pressure protection switch (LPS) and shorter than the recovery time of the high pressure protection switch (HPS) after the abnormal stoppage of the refrigeration equipment by the above-mentioned stop device (3), , the above protection circuit (
A determination means (51A) for determining whether the circuit (2) is energized or not, and a protection circuit (2) based on the determination by the determination means (51A).
) is energized, the low voltage protection switch (LPS
), and display means (52) for displaying the operation of the high voltage protection switch (HPS) when the protection circuit (2) is in a non-energized state.

A second solution is to identify the activation of each protection switch by using a starting relay arranged to prevent abnormal stoppage due to activation of the low pressure protection switch when the compressor is started.

Specifically, the measures taken by the invention of claim 2 are as follows:
It is assumed that the protection device for the refrigeration equipment is similar to the invention of claim 1, and furthermore, the protection circuit (2) is connected in parallel with the normally closed contact (63L) of the low pressure protection switch (LPS), A normally open relay contact (RyP) is provided that closes in response to the operation of 3).

[0010] A determining means (51B) for determining whether or not the protection circuit (2) is energized when the refrigeration system is abnormally stopped by the stopping device (3);
), when the protection circuit (2) is energized, the low voltage protection switch (LPS) is activated, and when the protection circuit (2) is de-energized, the high voltage protection switch (HPS) is activated. Display means (52) for displaying
).

[0011]

[Operation] From the above structure, in the invention of claim 1, when the refrigeration equipment is in operation, an excessive rise in the pressure on the high pressure side or an excessive drop in the pressure on the low pressure side occurs due to a change in the operating state, and one of the protection switches (HPS ), (LPS) is activated, the protection circuit (2
), the normally closed contacts (63H) and (63L) are opened, and the power supply to the protection circuit (2) is cut off, so that the refrigeration system is abnormally stopped by the operation of the stop device (3). At that time, the high pressure protection switch (HPS) and low pressure protection switch (L
PS) are connected in series in the protection circuit (2), either protection switch (HPS), (
However, in the present invention, the determining means (51A) activates the high voltage protection switch (H
When a predetermined time shorter than the recovery time of PS) has elapsed, it is determined whether or not the protection circuit (2) is energized. In other words, if the power is on, the normally closed contact (63L) that opened due to the activation of the low voltage protection switch (LPS) will close again due to the return, and if it is not energized, the normally closed contact (63L) will open due to the activation of the high voltage protection switch (HPS). This means that the open normally closed contact (63H) has not yet returned to its original state. And this discrimination means (
51A), the display means (52) indicates whether the high pressure protection switch (HPS) or the low pressure protection switch (
Since the operation of the protection switch (HPS) or (LPS) is displayed, it can be clearly identified which protection switch (HPS) or (LPS) is activated to cause the abnormal stop.

In the invention of claim 2, each protection switch (H
When the device abnormally stops due to the operation of S) and (LPS), the determining means (51B) determines the energization state of the protection circuit (2). At this time, the normally open contact (RyP) of the relay connected in parallel with the normally closed contact (63L) of the low voltage protection switch (LPS) is closed at the same time as the abnormal stop. In other words, the normally closed contact (63) of the low pressure protection switch (LPS)
Even if L) is opened, the protection circuit (2) remains energized, and if it is de-energized, the high voltage protection switch (HPS)
This means that the normally closed contact (63H) is open. Therefore, from the determination result of the determining means (51B), it is possible to identify which protection switch (HPS) or (LPS) is activated to cause the abnormal stop. In that case, the low pressure protection switch (LPS) is activated when starting the compressor.
) can be used to prevent the protection circuit (2) from being cut off due to activation, so there is no need to increase the cost of providing a separate member.
Control will be simplified.

[0013]

Embodiment A first embodiment of the present invention will be described below with reference to FIGS. 2 and 3. Figure 2 shows the refrigeration equipment control.
A protection circuit (2) for protecting each device of the refrigeration system is provided in a control circuit (1) connected to a single-phase AC power supply. A stop device (3) is disposed within the protection circuit (2) to abnormally stop the refrigeration device in response to an abnormality in the operating state of the refrigeration device. The protection circuit (2) is connected to one line (
A main path (2a) is provided connecting between a point (S) on line 1a) and a point (T) on the other line (1b). In the main path (2a), there are a normally closed contact (49F) of a temperature protection relay that operates when the compressor temperature rises, and a normally closed contact (2) of a compressor oil forming prevention relay.
6CH) and the normally closed contact (51C) of the fan motor overcurrent protection relay are interposed in series from the point (S) side, and the point (T) of this main path (3a). on the side,
The above-mentioned stopping device (3) is connected to the first and second terminals (3a) and (3b).
) are connected through. In addition, the above-mentioned stopping device (3)
Inside, a third terminal (3c) is provided on the first terminal (3a) side, and this third terminal (3c) is connected to the main path (2a).
) between the normally closed contact (51C) and the first terminal (3a) (P
) is provided between the main path (2a) and the first branch path (2b). Inside the first branch path (2b), there is a normally closed contact (63H) of a high pressure protection switch (HPS) that opens in response to an excessive rise in pressure on the high pressure side of the refrigeration equipment, and a normally closed contact (63H) in response to an excessive drop in pressure on the low pressure side of the refrigeration equipment. The normally closed contact (63L) of the low pressure protection switch (LPS), which opens when the The normally open contact (RyP) of the activated starting relay is connected. In addition, the first branch road (2b
The point (Q) between the normally closed contact (63L) and the third terminal (3c) of ) and the point (U) on the other line (1b) of the control circuit (1) are the second branch path (2c). connected by
The second branch path (2c) includes a normally open contact (RyC) of a protection relay (not shown) disposed in the stop device (3), and a compressor and fan stop relay (52C). are connected in series.

That is, during normal operation, the main road (
2a) and the first branch path (2b) are energized and the protective stop device (3) does not operate, but if the operating condition becomes abnormal and any of the normally closed contacts opens, the protective circuit (2) The protective relay in the stop device (3) is activated in response to the interruption of power supply, and the normally open contact (Ry) of the protective relay is activated in the second branch (2c).
When C) is closed, the compressor and fan stop relay (52C) is activated to abnormally stop the refrigeration system. At that time, by branching into the main path (2a) and the first branch path (2b) and providing each normally closed contact, it is possible to prevent an abnormal stop due to the activation of a high voltage or low voltage protection switch (LPS) and an abnormality caused by other protection switches. It is designed so that it can be distinguished from a stop. In addition, the low pressure protection switch (
By providing the normally open contact (RyP) of the start relay in parallel with the normally closed contact (63L) of the LPS), even when the low pressure at the time of starting the compressor is extremely low, it is possible to smoothly start the compressor without activating the stop device (3). This is designed to ensure proper start-up operation of the refrigeration equipment.

[0015] Here, the above-mentioned high voltage protection switch (HPS)
is activated when the high pressure side pressure rises excessively to about 28.0 (kg/cm2) and opens the normally closed contact (63H), and then the high pressure side pressure decreases to about 20.
5 (kg/cm2), it returns to the closed state, and the time required from this opening operation to return is about 10 seconds. In addition, the above low voltage protection switch (L
PS) is activated when the low pressure side pressure drops to approximately -0.3 (kg/cm2) and opens the normally closed contact (63L), and then when the device is stopped, the low pressure side pressure rises to approximately 0.5 kg/cm2. (
kg/cm2), it returns to the closed state, and the time required from this opening operation to return is within 2 seconds. And each protection switch (HPS),
When the (LPS) returns, the compressor and fan that had stopped abnormally will resume operation due to the operation of the stop device (3).
In other words, it is designed to return automatically.

Next, the control contents of the protection device when the high pressure protection switch (HPS) or the low pressure protection switch (LPS) is activated will be explained based on the flowchart shown in FIG. While the refrigeration equipment is operating, it is determined in step ST1 that the high pressure protection switch (HPS) or the low pressure protection switch (L
PS), one of the normally closed contacts (63H), (
63L) is opened, and when either of the protection switches (HPS) or (LPS) is activated, in step ST2, the refrigeration system is abnormally stopped by the activation of the stop device (3). Next, in step ST3, it is determined whether 2 seconds, which is sufficient for the low pressure protection switch (LPS) to return after the compressor has stopped, has elapsed, and when 2 seconds have elapsed, the process proceeds to step ST4. Protection circuit (2) (first
It is determined whether the branch path (2b)) is energized or not, and if it is energized, the process proceeds to step ST5 and the low voltage protection switch (L
PS) is activated, while the protection circuit (2)
If it is not energized, the process proceeds to step ST6, where it is displayed that the high voltage protection switch (HPS) has been activated. In other words, considering the difference in the return time of each protection switch (HPS) and (LPS), after a predetermined time of 2 seconds, which is longer than the return time of the low pressure protection switch (LPS) and shorter than the return time of the high pressure protection switch (HPS). By determining whether the protection circuit (2) is energized or not, which protection switch (HPS)
, (LPS) is activated.

In the above flow, by the control in step ST4, after the refrigeration system is abnormally stopped by the stop device (3), the recovery time of the low pressure protection switch (LPS) is longer than the recovery time of the high pressure protection switch (HPS). A determining means (51A) is configured to determine whether or not the protection circuit (2) is energized when a short predetermined period of time has elapsed.
), when the protection circuit (2) is energized, the low voltage protection switch (LPS) is activated, and when the protection circuit (2) is de-energized, the high voltage protection switch (HPS) is activated. Display means (52) for displaying
) is configured.

Therefore, in the first embodiment, during operation of the refrigeration system, an excessive rise in the pressure on the high pressure side or an excessive drop in the pressure on the low pressure side occurs due to changes in the operating state, and the protection switch (HPS) is activated.
, (LPS) is activated, one of the normally closed contacts (63
H) and (63L) are opened to cut off the power supply to the protection circuit (2). When the power to the protection circuit (2) is cut off, the relay in the stop device (3) is activated and its normally open contact (RyC) is closed, and the electromagnetic relay (50C) is activated to cause the compressor to , the fan stops, which means the refrigeration equipment stops abnormally. At that time, as in the above embodiment, for convenience of control, a high pressure protection switch (HPS) and a low pressure protection switch (LPS) are selected.
are connected in series in the protection circuit (2), either protection switch (HPS), (LPS
) has been activated, but in the above embodiment, the determining means (51A) determines that the protection circuit (2) (in the above embodiment It is determined whether the first branch path (2b)) is energized or not. Here, the high voltage protection switch (HPS)
) recovery time is about 10 seconds, and the low pressure protection switch (
Since the recovery time of the low pressure protection switch (LPS) is within 2 seconds, if the power is on, this means that the low pressure protection switch (LPS) has recovered, and it can be seen that the abnormal stop was caused by the operation of the low pressure protection switch (LPS). Further, if the power is not energized, this means that the high voltage protection switch (HPS) has not yet recovered, and it can be seen that the abnormal stop was caused by the operation of the high voltage protection switch (HPS). Then, according to the discrimination result of this discrimination means (51A),
The display means (52) indicates the high voltage protection switch (HPS).
Alternatively, since the operation of the low pressure protection switch (LPS) is displayed, it is possible to clearly identify which protection switch (HPS) or (LPS) is activated to cause the abnormal stop.

Next, a second embodiment according to the second aspect of the invention will be described with reference to FIG. In the second embodiment as well, the basic configuration of the electric circuit is the same as that shown in FIG. 2 in the first embodiment. FIG. 4 shows the control contents of the protection device. After performing the same control as steps ST1 and ST2 (see FIG. 3) in the first embodiment in steps SR1 and SR2, in step SR3, the starting relay is activated normally. Open contact (
Close RyP). Then, in step SR4, the energization state of the protection circuit (2) is determined.
In SR6, step ST5. in the first embodiment is performed. S
Control similar to T6 is performed. In the above flow, a determining means (51B) is configured to determine whether or not the protection circuit (2) is energized when the refrigeration system is abnormally stopped by the stop device (3) under the control of step SR3.

Therefore, in the second embodiment, when the device stops abnormally due to the activation of each of the protection switches (HS) and (LPS), the determination means (51B) determines whether the protection circuit (2)
The energization state of the is determined. At this time, in this embodiment, the normally open contact (RyP) of the starting relay connected in parallel with the normally closed contact (63L) of the low voltage protection switch (LPS) is closed at the same time as the abnormal stop. In other words, even if the normally closed contact (63L) of the low pressure protection switch (LPS) is opened, the first
The branch path (2b) is in a energized state, and if it is in a de-energized state, the normally closed contact (63) of the high voltage protection switch (HPS)
H) is now open. Therefore, the discrimination means (5
Which protection switch (HPS) is selected from the determination result of 1B)
, (LPS) actuation causes an abnormal stop.

[0021] Here, the above-mentioned starting relay normally operates when the compressor is started, and since the low pressure is low when the compressor starts, the normally closed contact (63L) is opened by the operation of the low pressure protection switch (LPS). Therefore, if left as is, the stop device (3) will be activated and the device will stop abnormally.
RyP) and is generally installed in refrigeration equipment. Therefore, by activating this activation relay at the same time as the abnormal stop, it becomes possible to identify which of the protection switches (HPS) and (LPS) has activated.
There is no need to provide a separate member, and there is an advantage that control can be further simplified.

[0022]

As explained above, in the invention of claim 1, the normally closed contact of the high voltage side protection switch and the normally closed contact of the low voltage protection switch are connected in series to the protection circuit as a protection device for the refrigeration equipment. However, a stop device is provided that abnormally stops the refrigeration equipment by cutting off the power to this protection circuit, and a predetermined period of time that is longer than the return time of the low voltage protection switch and shorter than the return time of the high voltage protection switch after the abnormal stop by the stop device is provided. If the protection circuit is energized, the low-voltage protection switch is activated, and if the protection circuit is not energized, the high-voltage protection switch is activated. Therefore, it is possible to identify which protection switch is activated to cause an abnormal stop with a simple configuration without providing any additional members.

According to the invention of claim 2, in addition to the invention of claim 1, as a protection device for a refrigeration equipment, a relay is connected in parallel with the normally closed contact of the low voltage protection switch and is closed at the same time as an abnormal stop. Since a normally open contact is provided to determine the energization state of the protection circuit at the same time as an abnormal stop, control can be simplified while utilizing the start relay provided in the refrigeration equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the invention.

FIG. 2 is an electric circuit diagram showing a part of the control circuit of the refrigeration apparatus according to the first embodiment.

FIG. 3 is a flowchart showing control details of the protection device in the first embodiment.

FIG. 4 is a flowchart showing control details of a protection device in a second embodiment.

[Explanation of symbols]

2 Protection circuit 3 Stopping device 51 Discrimination means 52 Display means HPS High voltage protection switch LPS low pressure protection switch 63H Normally closed contact 63L Normally closed contact RyP normally open contact

Claims (2)

[Claims] Claim 1: A high pressure protection switch (HPS) that opens due to an excessive rise in pressure on the high pressure side of a refrigerant circuit of a refrigeration system and then returns in response to a decrease in pressure; A low pressure protection switch (LPS) that resets according to the rise in
A protection circuit (2) that connects the normally closed contacts (63H) and (63L) of the (LPS) in series, and a stop device (3) that abnormally stops the refrigeration equipment when the protection circuit (2) is de-energized.
In the protection device for a refrigeration equipment, the high pressure protection switch (
When a predetermined time shorter than the recovery time of the HPS has elapsed, a determining means (51A) determines whether the protection circuit (2) is energized or not, and a protective circuit is activated based on the determination by the determining means (51A). When the circuit (2) is energized, it indicates the activation of the low voltage protection switch (LPS), while when the protection circuit (2) is de-energized, the high voltage protection switch (LPS) is activated.
1. A protection device for a refrigeration system, comprising: display means (52) for displaying operation of a HPS. 2. A high-pressure protection switch (HPS) that opens due to an excessive rise in pressure on the high-pressure side of a refrigerant circuit of a refrigeration system and then returns in response to a decrease in pressure; A low pressure protection switch (LPS) that resets according to the rise in
A protection circuit (2) that connects the normally closed contacts (63H) and (63L) of the (LPS) in series, and a stop device (3) that abnormally stops the refrigeration equipment when the protection circuit (2) is de-energized.
In the protection device for the refrigeration equipment, the protection circuit (2) is connected in parallel with the normally closed contact (63L) of the low pressure protection switch (LPS), and the stop device (3
) The normally open contact of the relay (RyP
), and a determining means (51B) for determining whether or not the protection circuit (2) is energized when the refrigeration system is abnormally stopped by the stopping device (3), and the determining means (51B).
), when the protection circuit (2) is energized, the low voltage protection switch (LPS) is activated, and when the protection circuit (2) is de-energized, the high voltage protection switch (HPS) is activated. Display means (52) for displaying
) A protection device for a refrigeration device, characterized by comprising: