JPS611976A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a refrigeration system in which a compressor is driven by an inverter.

[Prior art]

FIG. 6 is a block diagram showing a refrigerant circuit and a control circuit of a conventional refrigeration system using an inverter. In the figure, (1) is the compressor, (la) is the motor that drives the compressor, (2) is the nitrogen-cooled condenser, and the refrigerant discharged from the compressor +11 is sent to the heat transfer tube (2a). supplied, blower (2
b) Forced ventilation is performed to condense and liquefy. (
3) is a liquid receiver that receives the liquid refrigerant condensed and liquefied in the condenser (2), (4) is a cooling device that reduces the pressure of the liquid refrigerant supplied from the liquid receiver Fall, and (5) is the above-mentioned Squeezing device (4
), the evaporator completely cools the load by evaporating the liquid refrigerant reduced in pressure in ,Evaporator(
5) is connected to the closed loop by the refrigerant pipe (6) and the refrigeration cycle w! r.

(7) is a variable frequency inverter, (8) is a pressure detector that detects the refrigerant pressure on the low pressure side of this refrigeration circuit and generates a pressure detection signal according to that pressure, and (9) is the pressure detector mentioned above. Based on the pressure detection signal of (8), the inverter (7)
(10) is the power line of the inverter (7), (the river is the power line of the inverter (7)
) and the above motor (1a) are all connected to the 'ME source line, and 0 is the power supply line for the blower (2b), which is connected to the directional wave number power source for the turntable.

The conventional refrigeration system is constructed as described above, and the compressor I
The refrigerant discharged from the condenser (2) passes through the heat transfer tube (
2a), is cooled by the forced ventilation of the above-mentioned sending I@ machine (2b), and is condensed and liquefied to become a liquid refrigerant. This liquid refrigerant is received in the liquid receiver (3), and is further received in the expansion device (3).
The liquid refrigerant that is depressurized by this throttling device (4) is supplied to the evaporator (5), where it absorbs all of the heat from the cooling load, evaporates and vaporizes, and is sucked into the compressor ill. Therefore, when the cooling load on the evaporator (5) decreases, the evaporation pressure decreases, and the refrigerant pressure on the low pressure side of the refrigeration circuit, that is, the low pressure side of the compressor il+ decreases. Based on the pressure detection signal of the pressure detector (8) generated by detecting the refrigerant pressure on the low pressure side, the control circuit (9) completely decreases the output 1d wave number of the inverter (7) and the output of the compressor Il+. The rotation speed is lowered to reduce the cooling capacity and save power, and if the cooling load becomes too high, the refrigerant pressure on the low pressure side increases, so the above control is performed based on the pressure detection signal from the pressure detector (8). The circuit (9) increases the output frequency of the inverter (7) so that the cooling capacity matches the cooling load.
Cape J.

By the way, in the conventional refrigeration equipment as mentioned above, 50 Hz
In the district, the compressor (1) is used at an increased speed because there is no problem with the rotation speed of 60 Hz. However, since the power supplied to the blower (2b) is 50H2, the capacity as an air-cooled condenser is 90~8 at 60Hz.
It is 5%'8 degrees. As a result, the refrigerant pressure on the high-pressure side increases, causing a safety device such as a high-pressure switch to operate, causing the refrigeration system to stop operating. eliminate this drawback
Therefore, according to the results of the inventor's study, the above disadvantages can be overcome by using a 1-rank dog-sized condenser, but in that case, the product price will be on the same scale, and only 11 machines will have a larger tray. Although all of the above points can be solved by increasing the air flow rate, it has been found that in that case, other problems occur, such as increased noise and increased power consumption.

[Summary of the invention]

In view of the above-mentioned problems, this invention has been developed in such a way that even when the output frequency of the inverter is increased to increase the refrigeration capacity, the condensing pressure increases and safety devices such as the coronal pressure switch are activated and the refrigeration equipment is stopped. This was done with the sole purpose of solving all the problems such as the following: A variable frequency inverter and a pressure fii machine that is supplied with power from this inverter and rotates at a rotation speed that corresponds to the output frequency of the inverter. ,
A condenser that condenses and liquefies the refrigerant discharged from the compressor, a blower that forces air into the condenser, and a control that controls the power supply from the inverter to the J-A blower to keep the condensation pressure within a predetermined pressure. By providing a means and a t, the refrigeration system is constructed into four parts and all of the above objects are achieved.

[Embodiments of the invention]

FIG. 1 is a configuration diagram showing a refrigerant circuit and a control circuit of a refrigeration system showing one embodiment of the present invention, and FIG. 2 is a control circuit diagram for controlling power supply to the blower (2b) of the refrigeration system shown in FIG. be. In the figure, 111~X'J + (la), (
ga) and (go) are exactly the same as the refrigeration equipment shown in FIG. (One plow is a control means, (
1801a) is the a contact point of the electromagnetic contactor (1301), which is installed on the power line 0 to the blower (2b), and controls the power supply from the commercial same frequency source to the blower (2b). be. (1802d is an electromagnetic contactor (ISO
The a contact of g) connects the inverter (7) and the blower (2).
The power line connecting b) and t is installed in the power line (l) and controls the power supply from the inverter (7) to the blower (2b). It is a pressure switch whose contact (15a) closes when the pressure reaches a predetermined pressure. (1808) is a relay connected in series with the contact (15a'). (1808)
1)) is the b contact (iaoab) of the relay (18'08) connected in series with the electromagnetic contactor (1801).
It is. (18011:+) is the electromagnetic contact 5 (18
01) and the a contact (i) of the relay (1808).
aoaa) and are connected in series to the electromagnetic contactor (1802), respectively.

In the refrigeration system configured as described above, if the condensing pressure has not reached the predetermined pressure in an area where the power frequency is 50 Hz, the contact point (15) of the pressure switch (15)
a) is open and the relay (1308) is deenergized, so its b contact (1808b) is closed and the electromagnetic contactor (1801) is energized.

Thereby, the electromagnetic contactor (TAOG) is in a de-energized state. As a result, a of the electromagnetic contactor (1801)
+a point (1801a) is closed, and the above electromagnetic contactor (180
Since the a contact (1802a) of g) is open, the above blower (2b) receives the commercial frequency 50 from the power line Oz.
is powered and operating. When the output frequency of the inverter (7) increases from this state to 50 Hz to 60 Hz, the refrigerant pressure on the high pressure side rises and reaches a predetermined pressure, the contact (15a) of the pressure switch (15) closes and the relay ( 1808) is energized and its a contact (18Ha
) closes and its b contact (18Hb) opens, so the electromagnetic contactor (1301) is deenergized, and (7) 1) the contact (1801b) closes and the electromagnetic liquid lIl! Il vessel (1
802) is activated. As a result, the above electromagnetic contactor (1
The a contact (18Q1 &) of the above 1' electromagnetic contactor (1301i1) is opened, and the a contact (1802a) of the electromagnetic contactor (1301i1) is closed.
The output of [-wave number 7! ! ), the rotational speed increases, the condensing capacity of the I-cooled condenser (2) is increased, and the condensing pressure is controlled within a predetermined pressure. Therefore, in this embodiment, even if the output frequency of the inverter (7) increases, unlike conventional refrigeration equipment that uses an inverter, safety devices such as high-pressure switches will not operate and stop the refrigeration equipment. It is possible to continue operation by increasing the refrigerating capacity according to the cooling load.

In the above embodiment, the condensing pressure that has reached a predetermined pressure is detected by the full pressure switch (15), and the power supply to the blower (2b) is switched from the commercial frequency power line to the output side power line of the inverter (7). By switching and increasing the rotation speed of the blower (2b), the condensing capacity is increased and controlled to correspond to the increase in the rotation speed of the compression+fi Ill. By detecting this, a similar effect can be obtained by switching from the full commercial frequency power supply line 4 feeding the blower (2b) to the output power line of the inverter (7). shows another embodiment for improving the condensing capacity of the condenser (2), Oa detects the same wave number output from the inverter (7) and sends a frequency detection signal to the control means (131). When the output frequency of the inverter (7) reaches a predetermined frequency using the supplied frequency detector, the control means (1) closes its a contact (1804a) and energizes the relay (111108). The blower (2b) operates in the same manner as in the example, and the output frequency of the inverter (7) is supplied to the blower (2b), increasing its rotational speed and increasing the condensing capacity of the refrigerated condenser (2). Celebrated,
The condensing pressure will be controlled within a predetermined pressure. In addition,
! In Figure 8, Ill ~t8+ l river) ~H(i
aoxa) (xaoga) (la) (ga) (2b
) is the same as the x embodiment shown in FIG. 1 or indicates the f target portion. In Figure 4 (1801) (1801b)
(180!ri (1808) (1808&) (18
08b) is the same as the control circuit of the embodiment shown in FIG.

Also, Figure 5 shows the power supply to the blower (2b). Switch from the commercial frequency power line @ to the output side power line (I4) of the inverter (7) and connect the transmitter IflII machine (2b
4 is a control circuit diagram in this case. (7) is the heat exchanger tube (2a) of the condenser (2).
) is a temperature detector which detects the condensation kJ temperature of the refrigerant and supplies temperature detection signal No. 4 to the control means 1131. When the condensation temperature in the heat transfer #("a) reaches a predetermined temperature, the control means (1 field is the a contact point (1804) in FIG. 4).
→Close. Thereafter, in the same manner as in the above embodiment, the output frequency of the inverter (7) is supplied to the blower (2b), its rotational speed increases, the condensing capacity is increased, and the condensing pressure is kept within a predetermined pressure. uj is controlled.

In FIG. 5, Ill~t81t+ol~Q4) (
la) (illa) (Bb).

(1301a) (lH2a) is shown in Figure 1 - t - real m
mJ indicates the same or t target part. In the above embodiment, an electromagnetic contactor ft is used as the control means for controlling the power supply from the inverter (7) to the blower (2b), but the same effect can be obtained even if all semiconductors such as SCR are used. 〇〇〇〇　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　9. A condenser that condenses and liquefies the refrigerant discharged from the condenser, a blower that forces air into the condenser, and a control means that controls power supply from the inverter to the blower to keep the total condensation pressure within a predetermined pressure. Since the refrigeration system has been configured, even if the above inverter is controlled to increase its output frequency in order to increase the refrigeration capacity, the condensing pressure will increase and safety devices such as high-pressure force breakers will operate. We were able to solve problems such as continuous rotation stopping.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a refrigerant circuit and a control circuit of a refrigeration system according to an embodiment of the present invention, and FIG. 2 is a control circuit that controls power supply to the blower (2b) of the refrigeration system shown in FIG. figure,
FIG. 8 is a configuration diagram showing a refrigerant circuit and a control circuit of a refrigeration system according to another embodiment of the present invention, and FIG. In the configuration diagram shown in Fig. 4, Fig. 8, and Fig. 5, (
1) is the inverter, (1) is the compressor, (2) is the condenser%
(ga) is a heat exchanger tube, (2b) is a blower, 01 control means,
(taoυ (130g) is a magnetic contactor, (1!301a
) (1801b) are the electromagnetic contactors (l f3
01 ), (l1101a) is the a contact of the electromagnetic contactor (18H), (1aOf3) is the relay, and (1808a) and (1808b) are the a contact and b contact, respectively. (1304a) is the a contact of the control means, and (15) is the contact of the pressure switch (15). In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) A variable frequency inverter, a compressor that is supplied with power from this inverter and rotates at a rotation speed that corresponds to the output frequency of the inverter, a condenser that condenses and liquefies the refrigerant discharged from this compressor, and forced ventilation in this condenser. A refrigeration system comprising: a blower; and a control means for controlling power supply from the inverter to the blower and controlling condensing pressure within a predetermined pressure. (2) The refrigeration system according to claim 1, wherein the control means is an opening/closing means that closes when the condensing pressure reaches a predetermined pressure. (3) The refrigeration system according to claim 1, wherein the control means is an opening/closing means that closes when the output frequency of the inverter reaches a predetermined frequency. (4) The control means is an opening/closing means that closes when the condensation temperature reaches a predetermined temperature.
Refrigeration equipment as described in section.