JPH03177753A - Air conditioner - Google Patents

Abstract

PURPOSE:To suppress the over-rising of a discharge of a discharged pressure at the time of returning to a normal state operation of the subject device, by a method wherein, when a discharge pressure has become above the first specified pressure, a motor-operated valve is opened, and after a specified time has elapsed and evaporation pressure has risen above a specified valve, the operation capacity of a blower is lowered; and when the discharged pressure has lowered below the second specified pressure, the motor-operated valve is closed. CONSTITUTION:At the time of warming operation, and discharge pressure Pd being detected by a detector 13 fixed to a piping of a compressor 1 is above the specified value Pd1 a mean 14 for controlling a motor-operated valve, said valve 9 is made to be opened, a part of a coolant is made to flow through a by-pass 10, resulting in the loweing of the discharge pressure, while when the working time set by the time measuring means 16 for the motor reaches a spcifiedvalue, and when the evaporation pressure T of an outdoor heat exchanger 3 measured by a steam pressure detector 18 is more than the specified value T1, then a blower capacity control means 15 lowers the operating capacities of the blowers 7a - 7c. On the other hand when the discharge pressure detector 14 detects that the discharged pressure lowers to a specific value pd2 (herein, Pd1 is larger than Pd2), the motor-driven valve controller 14 closes the valve 9, with the operating capacities of the blowers 7a - 7c in the state as being lowered.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air conditioner, and particularly relates to evaporation pressure control of an air conditioner using a capacity controllable outdoor blower related to a refrigeration cycle and a control device. .

[Conventional technology]

The configuration of a conventional air conditioner is shown in FIG. 3. In FIG. 3, 1 is a compressor that compresses and discharges the gas refrigerant sucked in;
2 is a cooling operation side, [1 is a four-way valve that switches to the room operation side, 3 is an outdoor heat exchanger, 4 is a pressure reducing device that converts the high-pressure night refrigerant into a low-pressure gas-liquid mixed refrigerant, 5 is an indoor heat exchanger, 6 is an accumulator for separating refrigerant into gas and liquid, and 6a is an oil return device constructed by drilling a hole in the middle of the outflow pipe of the accumulator 6. Here, the four-way valve 2 is connected to a discharge port of the compressor 1 , one end of the outdoor heat exchanger 3 , one end of the indoor heat exchanger 5 , and an inlet of the accumulator 6 . 7a1b, 1c are outdoor blowers for sending air to the outdoor heat exchanger 3; 8 is a compressor 1;
a pressure sensor for detecting the discharge pressure provided in the discharge pipe; 9;
11 and 12 are gas-side extension pipes and WL1!, which are examples of electric valves that control the flow rate of refrigerant in the bypass passage 10 connected between the discharge pipe and the inlet pipe of the accumulator 6, respectively. This is I11 extension piping. The other end of the outdoor heat exchanger 3 and the pressure reducing device 4 connected to the other end of the indoor heat exchanger 5 are connected by a liquid side extension pipe 12 . 13 is a discharge pressure detecting means connected to the pressure sensor 8, and 14 is a solenoid valve control means for controlling the opening and closing of the solenoid valve 9 according to the output from the discharge pressure detecting means.

In the figure, solid line arrows indicate the direction of refrigerant flow during cooling operation, and broken line arrows indicate the direction of refrigerant flow during heating operation.

Next, the operation during cooling operation will be explained. The high-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 1 flows into the outdoor heat exchanger 3 via the four-way valve 2, and is then passed through the outdoor blowers 7a and 7b.
, 7c, while the heat is radiated to the outdoor air, the refrigerant condenses to become a high-pressure liquid refrigerant, passes through the liquid side extension pipe 12, is depressurized by the pressure reducing device 4, and becomes a low-pressure gas-liquid mixed refrigerant. It is supplied to the indoor heat exchanger 5. In the indoor heat exchanger 5, heat is collected from the indoor air for cooling, while the refrigerant evaporates to become a low-pressure gas refrigerant, which flows into the accumulator 6 via the gas side extension pipe 11 and the four-way valve 2. In the accumulator 6, the liquid refrigerant and gas refrigerant that were not completely evaporated in the indoor heat exchanger 5 are separated and sucked into the compressor a1, while
A mixed liquid of refrigerant and refrigerating machine oil accumulated at the bottom of the accumulator 6 is sucked into the compressor 'al through an oil return device 6a to maintain an appropriate amount of oil necessary for lubrication inside the compressor @1.

Next, the operation during heating operation will be explained.

The gas refrigerant is compressed at a pressure of ff1ll, and the discharged high-temperature, high-pressure gas refrigerant flows into the indoor heat exchanger 5 via the four-way valve 2 and the gas side extension pipe 11, and radiates heat to indoor air to heat it, The refrigerant is condensed to become a high-pressure liquid refrigerant, which is depressurized by the pressure reducing device 4 to become a low-pressure gas-liquid refrigerant, and then supplied to the outdoor heat exchanger 3 through the liquid-side extension pipe 12. In outdoor heat exchanger 3, is it an outdoor blower? The refrigerant is evaporated by collecting heat from the outdoor air by the blowing action of the refrigerant a, 7b, and 7c, becomes a low-pressure gas refrigerant, and flows into the accumulator 6 via the four-way valve 2. In Akiemureta 6, outdoor heat exchanger 3
The liquid refrigerant and gas refrigerant that were not completely evaporated are separated, while the gas refrigerant and refrigerating machine oil necessary for the compressor 1 are returned.

The operation of such an air conditioner will be explained with reference to FIG.

After heating starts in step 19, when the load increases, the pressure of the refrigerant gas discharged from the compressor 1 increases. In particular, since the capacity of the heat exchanger for condensing the refrigerant gas during heating, that is, the indoor heat exchanger 5, is small, the discharge pressure tends to increase. When the means 13 detects that the discharge pressure P is equal to or higher than the first predetermined value 20, the solenoid valve control means 14 opens the solenoid valve 9 in step 22 to allow a part of the refrigerant in the bypass path 10 to flow. Decrease discharge pressure.

After that, in step 25, the discharge pressure detection means 13 determines the discharge pressure P to a second predetermined value Po (however, pH<Pa1).
It is determined whether or not the discharge pressure P4 is equal to or less than a second predetermined value P.

In the following cases, the solenoid valve control means 14 closes the solenoid valve 9 in step 29 to return to the normal operating state.

[Problem to be solved by the invention]

Conventional air conditioners are configured as described above.
Once the solenoid valve 9 is opened, no control is performed until the discharge pressure falls below a predetermined value, so the evaporation pressure increases due to the influence of the discharge gas refrigerant that has flowed in through the bypass path IO, and the compressor The amount of refrigeration oil discharged from 1 increases,
Pressure! II! There were issues such as the risk of causing a loss of 1.

This invention was made to solve the above problems, and after the discharge pressure exceeds a predetermined value and the electric valve opens, the evaporation pressure is maintained appropriately and the discharge of refrigerating machine oil from the compressor is suppressed. The purpose is to obtain an air conditioner that is designed to

[Means to solve the problem]

The air conditioner according to the present invention includes a bypass path connected to an accumulator inflow pipe via a solenoid valve from the middle of a connecting pipe between a compressor and a four-way valve, a plurality of blowers for sending air to an outdoor heat exchanger, A blower capacity control means for controlling the operating capacity of the blower, an electric valve control means for controlling the opening/closing operation of the electric valve, an electric valve operation timer for measuring the operation time of the electric valve, and installed on the liquid side piping of the outdoor heat exchanger. and a discharge pressure detection means attached to the discharge piping of the compressor, and when the discharge pressure detected by the discharge pressure detection means is equal to or higher than a first predetermined value, the electric valve control means opens the electric valve. At the same time, when the time measured by the electric valve operation timing means reaches a predetermined value, and the evaporation pressure measured by the evaporation pressure detection means is equal to or higher than the predetermined value, the operating capacity of the blower is reduced by the blower capacity control means, Thereafter, when the discharge pressure determined by the discharge pressure detection means becomes equal to or lower than the second predetermined value, the electric valve control means closes the electric valve while the operating capacity of the blower is reduced.

[For production]

In this invention, when the discharge pressure is equal to or higher than the first predetermined value, the motorized valve control means opens the motorized valve, and when the time measured by the motorized valve operation timing means reaches a predetermined value, the evaporation pressure is set to the predetermined value. In such a case, since the operating capacity of the blower is reduced by the blower capacity control means, it is possible to suppress the rise in evaporation pressure, suppress the discharge of refrigerating machine oil from the compressor, and also suppress the rise in discharge pressure. Also, after that, the discharge pressure becomes the second level.
When it becomes below a predetermined value, the electric valve control means closes the electric valve while the operating capacity ffl of the blower is decreased, so that an increase in the discharge pressure can be suppressed even when normal operation is resumed.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
The figure is an overall configuration diagram of an air conditioner according to an embodiment of the present invention. In Figure 1, 1~6°6a, 7a~7c
(-7), 8 to 14 are the same as the parts with the same symbols in the air conditioner shown in FIG. 3, and their explanation will be omitted. 15
Reference numeral 16 indicates an outdoor air blower m whose input side is connected to the magnetic valve 9 and the air blower capacity control means 15.
, 7 is reduced or the solenoid valve 9 is opened. 1
7 is a pressure sensor attached to the pipe near one end of the outdoor heat exchanger 3 to detect the evaporation pressure between the outdoor heat exchanger 3 and the pressure reducing device 4; 18 is the evaporation pressure detection from the pressure sensor I7 This is an evaporation pressure detection means that inputs a signal and compares the magnitude with a set value to determine the level of evaporation pressure.It is bidirectionally connected to the discharge pressure detection means 13, and the output side is also connected to the blower capacity control means 15. It is connected. Further, the input side of the discharge pressure detection means 13 is also connected to the electromagnetic valve operation timer means 16 and the blower capacity control means 15. In addition,
In the figure, solid line arrows indicate the direction of refrigerant flow during cooling operation, and broken line arrows indicate the direction of refrigerant flow during heating operation.

FIG. 2 shows the control flow rate when the discharge pressure increases during heating operation.

Regarding the operation of refrigerant during cooling and heating operations, see Part 3.
Since the operation is exactly the same as that of the conventional air conditioner shown in the figure, the explanation thereof will be omitted, and the operation when the load increases and the discharge pressure increases will be explained based on FIG. 2.

Heating operation starts in step 19, and normally in step 20
As shown in FIG.
represents the number of outdoor fans in operation, and all the fans are in operation. The ON-FF relationship between fan step N and outdoor ventilation @ 1a to 7c is as follows: The heating load increases, the discharge pressure rises, and in step 21, the discharge pressure detection signal 3 determines the discharge pressure P.

has exceeded the first predetermined value P4 (however, the discharge pressure detection means 13 uses the discharge pressure detection signal corresponding to P4 input from the pressure sensor 8 and the first setting corresponding to the first predetermined value P41) ), the solenoid valve control unit 14 receives this determination result in step 22.
This opens the solenoid valve 9. At this time, in step 23, i
When the m-valve operation timer 16 resets the solenoid valve operation time to zero and becomes magnetized, the discharge pressure detection means 13 which receives this elapsed signal from the iim-valve operation timer 16 detects the discharge pressure P in step 25. , is the second predetermined value P. In other words, the discharge pressure detection signal equivalent to P4 from the pressure sensor 8 and P.

The determination is made by comparing the magnitude with a corresponding second set value. If the discharge pressure P4 is less than or equal to the second predetermined value P4
Close the circuit.

In step 25, the discharge pressure P is set to a second predetermined value P.
. If it is determined that the determination result is not below, the evaporation pressure detection means 18 receives this determination result from the discharge pressure detection means 13 and detects the evaporation pressure P from the pressure sensor 17.

By comparing the magnitude of the corresponding evaporation pressure detection signal and the evaporation pressure set value corresponding to the predetermined value Pal, the evaporation pressure P is determined to be the predetermined value Pa1.
Determine whether or not the value is greater than or equal to the value. If the evaporation pressure P is greater than or equal to the predetermined value Pe+, the blower capacity control means 1 receives this determination result.
5, it is determined in step 27 whether the fan step N exceeds 1, and if the fan step N exceeds 1, the fan step N is stepped down by one step in step 28. When the determination result that the evaporation pressure P is not greater than the predetermined value Pa1 is received from the evaporation pressure detection means 18 in step 26, or the determination result that the fan step N does not exceed 1 in step 27, the blower capacity control means 15, the discharge pressure detection means 13 performs the process of step 25. Further, the electromagnetic valve operation timing means 1 receives a signal indicating that step 28 has been processed from the blower capacity control means 15.
Step 6 returns to step 23 and repeats the above operation.

After the solenoid valve 9 is closed in step 29 as described above, the discharge pressure detection means 13 returns to step 21 and repeats the above operation. In addition, in the above operation, fan step N
If it is less than 1, no further step-down is performed, and even if the discharge pressure P4 becomes less than the second predetermined value and the solenoid valve 9 closes, the operating capacity of the outdoor blower 7 remains unchanged. The fan step N is maintained while decreasing until the outdoor blower 7 stops.

In the above embodiment, a sensor or the like that detects the pipe temperature and converts it into evaporation pressure may be used instead of the pressure sensor 17.

Further, pressure can also be determined by using a pressure switch instead of a pressure sensor and detecting whether the pressure switch is turned on or off.

(Effects of the Invention) As described above, according to the present invention, when the discharge pressure is higher than the first predetermined value, the electric valve provided in the bypass path between the inlet pipe of the accumulator and the discharge pipe of the compressor is opened. At the same time, when a predetermined time has elapsed since the opening, if the evaporation pressure is above a predetermined value, the operating capacity of the blower is reduced, and when the discharge pressure becomes below a second predetermined value, the operating capacity of the blower is reduced. Since the electric valve is configured to close while the evaporation pressure is decreasing, it is possible to suppress the increase in evaporation pressure and discharge of refrigerating machine oil from the compressor, and also to suppress the increase in discharge pressure. Even when the compressor is restored, the increase in discharge pressure can be suppressed, which has the effect of improving the reliability of the compressor and the safety of the air conditioner.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an air conditioner according to an embodiment of the present invention, FIG. 2 is a control flowchart when the discharge pressure increases during heating operation, and FIG. 3 is an overall configuration diagram of a conventional air conditioner.
FIG. 4 is a control flowchart during conventional heating operation. In the figure, 1... compressor, 2... four-way valve, 3... outdoor heat exchanger, 4... pressure reducing device, 5... indoor heat exchanger,
6... Accumulator, 7a, 7b, 7c... Outdoor blower, 8... Pressure sensor, 9... Solenoid valve, 13...
...Discharge pressure detection means, 14...Solenoid valve control means, 1
5...Blower capacity control means, 16...Solenoid valve operation timing means, 17...Pressure sensor, 18...Evaporation pressure detection means, (8°13)...Discharge pressure detection means, (17
, 18)...Evaporation pressure detection means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] A refrigerant circuit to which a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and an accumulator are connected via piping, and an inflow piping for the accumulator via an electric valve from the middle of the connecting piping between the compressor and the four-way valve. bypass path connected to
a plurality of blowers that can be operated individually to send air to the outdoor heat exchanger; blower capacity control means for controlling the operating capacity of the blowers; electric valve control means for controlling opening and closing operations of the electric valve; an electric valve operation timer for timing the operating time of the compressor; an evaporation pressure detector for detecting the pressure between the outdoor heat exchanger and the pressure reducing device; and a discharge pressure detector attached to the discharge piping of the compressor. and when the discharge pressure detection means detects that the discharge pressure is equal to or higher than a first predetermined value, the electric valve control means opens the electric valve and operates the electric valve operation timing means, and the electric valve operation timing means opens the electric valve and operates the electric valve operation timing means. If the evaporation pressure is detected by the evaporation pressure detection means to be above a predetermined value when the time measured by the timer reaches a predetermined value or more, the blower capacity control means decreases the capacity of the blower, and then the discharge pressure If the detection means detects that the discharge pressure is equal to or lower than a second predetermined value, the electric valve control means closes the electric valve while the operating capacity of the blower is reduced. harmonizer.