JPH036359B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an improvement in a rotary compressor in which liquid is discharged into a compression chamber of the rotary compressor to perform cooling, lubrication, and sealing functions. [Prior Art] Generally, as shown in FIG. 2, this type of compressor includes a pump 2 that is constantly driven to rotate while the rotors 12 and 22 of the compressor are rotating, and the pump 2 pumps liquid into the compression chamber 17. , 27 and discharged together with the gas from the compressor is stored together with the gas in a tank 5, and the liquid separated from the gas in the tank is supplied to the pump. On the other hand, when the demand for compressed gas decreases, the compressor activates a load reduction device to reduce or block the intake area of the compressor cylinder using a blockage valve when the pressure in the tank exceeds a predetermined value. By reducing or eliminating the suction gas of the compressor and simultaneously reducing the rotation of the prime mover as necessary, low-load or no-load operation is performed, and power consumption is reduced. By the way, during the above low load or no load operation,
Due to the operation of the blocking valve, very little gas is drawn into the compression chamber of the compressor, whereas cooling, lubricating or sealing liquid is discharged into the compression chamber in proportion to the rotational speed of the compressor rotor. Therefore, a flow rate adjustment valve is provided that reduces the amount of liquid sent from the tank to the pump in synchronization with the decrease in the intake opening of the compressor due to the blockage valve, and a The invention of Japanese Utility Model Publication No. 55-22227 and Japanese Unexamined Patent Application Publication No. 1983-1987 discloses a system in which a second pump is provided and the gas stored at the discharge port of the compressor casing and the liquid separated from the gas are returned to the tank by the pump. This is proposed in the invention of No. 45315. FIG. 2 shows an air compressor implementing the invention of JP-A No. 51-45315, in which a first-stage compressor 11, a second-stage compressor 21, a first pump 2 and a second The pump 3 is arranged in series with a motor 1 whose rotation speed is constant, and the motor 1 drives the compressors 11 and 21.
The rotors 12, 22 and the rotors of the pumps 2, 3 are driven to rotate, respectively. compressor 11,
12 are both screw type, rotor 1
Reference numerals 2 and 22 each consist of a male type screw and a female type screw, and these screws are rotated in synchronization in opposite directions to compress the gas in the axial direction, and the air sucked from the filter 6 is The air is sucked into the suction port 14 of the first stage compressor 11 through the through hole 33 of the load reduction device 31, and the compressor 11
It is compressed by the compressor 17 and enters the suction port 24 of the second stage compressor 21 from the discharge port 15, and is compressed by the compressor 21.
It is compressed in the compression chamber 27 and stored in the tank 5 through the discharge port 25 and the non-return valve 4. Oil for lubricating, sealing, and cooling the compressors 11 and 21 is supplied from the discharge port of the first pump 2 through the passage 51 to the through hole 16 formed in the casing 13 of the first compressor 11 and to the second stage compressor. 21 casing 2
The air is injected into the compression chambers 17 and 27 of the compressors 11 and 21 through the through holes 26 formed in the second stage compressor 21, and is discharged together with the compressed air through the discharge port 25 of the second stage compressor 21 and into the tank 5. sent. A separator (not shown) that separates air and oil is built into the tank 5, and the oil accumulated at the bottom of the tank 5 passes through the oil outlet 44, the passage 52, the cooler 9, the passage 53, and the filter 7. , through the flow rate adjustment valve 8, the passage 54
The water is returned to the suction port of the first pump 2 and circulated. The second pump 3 sucks the oil separated at the discharge port 25 of the second stage compressor 21 from the drain 28 through a passage 55 to the suction port of the pump 3, and from the discharge port passes through a passage 56 to the oil return port 4.
The water is refluxed into the tank 5 from 7. As disclosed in Japanese Unexamined Patent Publication No. 51-45315, the load reduction device is a pressure regulating valve that is guided from the tank 5 when the air pressure in the tank 5 rises and reaches a predetermined regulating pressure point. Due to the balance between the air pressure introduced into the pressure chamber 38 via the pressure reducing valve (not shown) and the air pressure introduced from the tank 5 into the pressure chamber 37 via the pressure reducing valve (not shown), the piston 36
is moved to operate the blockage valve 34 to open the through hole 3.
3 to make the intake air amount of the first stage compressor 11 zero, the air pressure from the pressure regulating valve is simultaneously distributed to the flow regulating valve 8, and the valve body built in the valve 8 is moved by the air pressure, and the passage 53
and 54 is configured to narrow the area of the internal passage within the flow rate regulating valve 8. [Problems to be Solved by the Invention] In the rotary compressor configured as described above, the blockage valve 34 is closed while compressed air is being consumed from the compressed air outlet 60 of the tank 5. 33
is fully opened, the compressors 11 and 21 are in a full-load operating state in which they compress air and discharge compressed air into the tank 5, and the oil is supplied to the compressors 11 and 2 by the first pump 2.
However, when the consumption of the compressed air taken out from the compressed air outlet 60 decreases or stops, the air pressure in the tank 5 rises, and when it reaches a predetermined value, the air pressure increases as shown in the figure. Load reduction device 31 by air pressure from a pressure regulating valve that does not
In this case, the blockage valve 34 completely closes the through hole 33 to make the intake air zero, and the pump 3 discharges and removes the air and oil in the discharge port 29 (the space from the discharge port 25 to the non-return valve 4). The return valve 4 is closed, the pressure in the discharge chamber is significantly reduced, rotor back pressure is removed, and no-load operation is started. At this time, the first stage compressor 11
The amount of air taken into the compressor 1 and the amount of air discharged into the discharge chamber become zero, but due to the action of the flow rate adjustment valve 8,
The supply of a minimum amount of oil for lubrication of parts 1 and 21 is ensured. However, the first pump 2
Since the flow rate regulating valve 8 throttles the oil flow rate on the suction side of the flow rate regulating valve 8, the passage 54 becomes in a vacuum state and an abnormal noise called vacuum sound is generated from the pump 2. At the same time, the cooler 9 on the upstream side of the flow rate regulating valve 8 Since the amount of oil flowing through the cooler is also drastically reduced, the heat transmission coefficient of the cooler is reduced. In the compressor configured as described above, in the unlikely event that the blocking valve 34 of the load reduction device 31 does not completely block the through hole 33, the flow rate of air is reduced between the blocking valve 34 and the through hole 33. When a state of incomplete closure occurs in which a small gap remains, a small amount of air is drawn into the compression chambers 17, 27 from the gap and is compressed to generate compression heat. However, because only the minimum amount of liquid is supplied to the compression chambers 17 and 27 due to the action of the flow rate adjustment valve 8, the liquid for cooling, lubrication, and sealing is superheated and flows into the discharge chamber 29 together with the compressed air. If the state in which the air intake of the load reduction device 31 is incompletely blocked continues such that the liquid is discharged and recirculated into the tank 5, the temperature of the liquid in the tank 5 increases. Furthermore, in a compressor that does not include the second pump 3, if the load reduction device 31 is incompletely blocked, the superheated liquid will remain in the discharge chamber 29 together with the compressed air, causing the non-return valve 4 to close. Since only the amount exceeding the applied pressure is refluxed into the tank 5, there is a risk that the compressor casing 23 may also be overheated. The same applies if the second pump 3 should experience incomplete suction. When the compressed air and liquid remain in the discharge chamber 29, the pressure in the discharge chamber acts as back pressure on the rotor of the compressor, and even when the load reduction device 31 is in operation, the power consumption decreases by only about 70%. . [Means for solving the problem] In a rotary compressor that is operated by injecting cooling, lubricating, and sealing liquid into the compression chamber, when a load reduction device is installed and the no-load operation is performed, the above-mentioned It is advantageous in terms of power consumption to reduce the amount of liquid supplied to the compression chamber in synchronization with the operation of the load reducing device at the same time as the load reducing device blocks and interrupts the intake gas. For this purpose, a flow rate regulating valve that operates in synchronization with the operation of the load reduction device is usually disposed in the liquid passage of the pump that supplies liquid to the compression chamber, but on the suction side of the pump. In a simple oil passage configuration, in which the oil passage is connected to the liquid discharge port of the tank via the cooler, and the discharge side of the pump is connected by an oil passage to a through hole that communicates with the compression chamber of the compressor casing, the flow rate is Even if the regulating valve is disposed in the oil passage on the suction side of the pump, or even if it is disposed in the oil passage on the discharge side of the pump, when the flow rate regulating valve throttles the liquid flow rate, the pump is stopped. The problem is not solved because the liquid flow rate through the cooler is reduced and therefore the liquid flow rate through the cooler is reduced. The present invention includes a casing of a compressor, a compressor rotor that is driven by a prime mover and is rotatable within a compression chamber of the casing, a pump that is rotationally driven during rotation of the rotor, and a pump that is connected to a discharge port of the pump and that is rotatable within a compression chamber of the casing. a passage for supplying liquid for cooling, lubricating and sealing the compressor discharged by the pump into the compression chamber;
a tank for storing the gas and liquid discharged from the casing and supplied via the non-return valve; a load reduction device for adjusting the opening degree of the absorption port of the compression chamber according to the internal pressure of the tank; and the load. In a rotary compressor provided with a flow rate adjustment valve that adjusts the flow rate of liquid supplied to the compression chamber in synchronization with the adjustment of the opening of the suction port of the compression chamber by a reducing device, a passage for supplying liquid to the compression chamber is provided. It is connected to the discharge port of the pump via the flow rate adjustment valve, and the suction port of the pump and the liquid discharge port of the tank are connected via a cooler, and the liquid return port of the tank and the liquid discharge port of the tank are connected to each other via a cooler. Either one of the passages between the outlet and the cooler and the discharge port of the pump are connected so that when the pressure at the discharge port of the pump exceeds a predetermined value, excess pressure liquid is returned to the tank side. The invention is characterized in that the fluid is connected via a relief valve that prevents the liquid from being discharged from the pump even when the flow rate adjustment valve throttles the flow rate to the passage that supplies liquid to the compression chamber in synchronization with the operation of the load reduction device. The surplus liquid flowing through the pump is made to flow to the tank side via a relief valve, and the flow rate of the liquid flowing through the pump and therefore the flow rate of the liquid flowing through the cooler is increased regardless of the operating state of the load reduction device, This is an attempt to solve the above problems. [Operation of the Invention] According to the present invention, while the rotor of the rotary compressor is rotating, the pump is driven, and liquid is sucked from the liquid discharge port of the tank through the cooler and from the suction port. The discharge side of the pump communicates with at least one of a passage supplying liquid to the compression chamber and a passage between a liquid return port of the tank and a pre-discharge port of the tank and the cooler via a relief valve. Therefore, when a large amount of liquid is supplied to the compression chamber for cooling, lubrication, and sealing, such as when a rotary compressor is operating at full load, the liquid discharged from the pump is transferred to the tank via the relief valve. When the load reduction device is activated and the flow rate adjustment valve limits the amount of liquid supplied to the compression chamber, the surplus liquid discharged from the pump is The flow rate of the liquid flowing through the pump is kept unchanged regardless of the operating status of the rotary compressor, and the flow rate of the liquid flowing through the cooler is made independent of whether the load reduction device is in operation or incompletely operated. and cool it down. [Description of Embodiment] Fig. 1 shows an embodiment of the present invention in which the present invention is applied to a rotary compressor of the same type as Fig. 2, and the same parts as in Fig. 2 are given the same reference numerals. This is what was shown. The rotary compressor has a motor 1, a first stage compressor 11, a second stage compressor 21, a first pump 2, and a second pump 3 arranged in series, and the motor 1 drives the compressors 11, 12 and the pump 2. , 3. 1st stage compressor 11 and 2nd stage compressor 11
The stage compressor 21 is of a screw type, and has a pair of male rotor and female rotor (hereinafter simply referred to as rotor 1).
2 and 22) are in mesh with each other, compressing the air taken in from the suction port 14 of the casing 13 of the first stage compressor 11 and discharging the compressed air from the discharge port 25 of the second stage compressor 21 through the non-return valve 4. It is configured such that the water is stored in the tank 5 through the. 1st stage compressor 11
The casing 13 is provided with a filter 6 and a load reduction device 31 connected to the suction port 14,
The air is passed through the filter 6 and the machine frame 32 of the load reduction device 31.
The air is sucked into the suction port 14 of the compressor casing 13 through the through hole 33 . The load reduction device 31 includes a blockage valve 34 mounted on the machine frame 32 so as to be able to reciprocate in the axial direction, and a piston 36 fixed to a shaft 35 of the blockage valve 34.
It is equipped with pressure chambers 37 and 38 that are divided into individual parts,
When the pressure in the tank 5 rises and reaches a predetermined adjustment pressure point, air pressure is introduced into the pressure chamber 38 through a gas pipe led from the tank 5 and a pressure adjustment valve (both not shown). With the balance of the reduced air pressure branched from the gas pipe and introduced into the pressure chamber 37 via a pressure reducing valve (not shown),
The piston 36 is actuated to close the closure valve 34.
This allows the opening area of the through hole 33 to be fully opened or the through hole 33 to be completely closed. Motor 1
is an induction type with a constant rotation speed, and is in a loaded operation state while the closing valve 34 fully opens the through hole 33 and performs the compression action of the compressor; In this case, the pressure in the discharge chamber 29 of the compressor (the space from the discharge port 25 to the non-return valve 4) is significantly reduced by removing air and oil from the drain 28 using the second pump 3. By removing the back pressure acting on the rotor, the power consumption is reduced to 20% or less of full load, resulting in no-load operation. Lubricating oil as a liquid for cooling, lubrication, and sealing is sent from the discharge port of the first pump 2 through the passage 40 to the passage 41 via the filter 7 and the flow rate adjustment valve 8, and then through the passage hole 16 of the casing 13. first through
to the compression chamber 17 of the stage compressor 11, and to the casing 2
It is discharged into the compression chamber 27 of the second stage compressor 21 through the through hole 26 of No. 3. The oil discharged into the compression chambers 17, 27 of the compressors 11, 21 is transferred to the rotors 12, 2.
The sliding surface of the second stage compressor 21 is lubricated and sealed, and the discharge chamber 2 of the second stage compressor 21 is cooled together with the compressed air.
5 and enters the tank 5 together with compressed air via the non-return valve 4. A separator (not shown) for separating air and oil is built in the tank 5, and the oil is stored in the lower part of the tank 5. The suction port of the first pump 2 is communicated with the oil outlet 44 of the tank 5 via a passage 42, a cooler 9 and a passage 43, and the oil separated from air in the tank 5 is cooled by the cooler 9. The pressure is increased by the first pump 2 to lubricate the compressors 11 and 12, and the fluid is circulated back to the tank 5. On the other hand, the second pump 3 has its suction port connected to the discharge chamber 2 of the second stage compressor 21 via the passage 45.
It communicates with a drain 28 provided in the oil reservoir section 9, sucks oil discharged from the discharge port 25 and separated from air in the discharge chamber 29, and drains the oil from the tank 5 through a passage 46 from the discharge port. To the oil return port 47 or to the passage 49 and passage 4 shown in dotted lines.
The oil is returned to the oil passage 43 that connects the oil outlet 44 and the cooler 9 via the oil outlet 8 . The flow rate adjustment valve 8 is the same known type as shown in FIG. 2, and the pressure gas is introduced through the pressure adjustment valve.
When the built-in valve body moves due to the pressure of the pressurized gas, the internal passage area of the regulating valve 8 that communicates from the passage 40 to the passage 41 is narrowed.When the air pressure in the tank 5 reaches a predetermined regulation pressure point, The flow rate is adjusted so that the internal passage of the regulating valve 8 is narrowed in two stages or steplessly in synchronization with the closing of the suction hole 33 in the load reducing device 31. The control method for the flow rate regulating valve is not limited to the one shown in the drawings, but the method described in Japanese Utility Model Publication No. 55-22227, which is directly controlled by the movement of the closing valve 34, can also be used. Reference numeral 50 indicates a relief valve, which allows excess pressure oil to flow back to the passage 43 through the passage 48 when the oil pressure in the passage 40 connected to the discharge port of the first pump 2 exceeds a predetermined value, or as shown in the dotted line diagram. aisle 49
This is a control valve that allows liquid to flow in only one direction as described above. When configured as described above, oil passes through the passage 43 from the oil discharge port 44 of the tank 5, is cooled by the cooler 9, is sucked into the first pump 2 through the passage 42, and from the discharge port passes through the passage 40, The flow rate is adjusted by the flow rate adjustment valve 8 through the filter 7, and the flow is passed through the passage 41 and the through hole 16 of the casing 13 to the compression chamber 17 of the first stage compressor 11. through the second stage compressor 21
are injected and supplied to the compression chambers 27, respectively. The oil injected into the compression chambers 17 and 27 flows into the second chamber together with the compressed air.
The oil is returned from the discharge port 25 of the stage compressor 21 through the discharge chamber 29 into the tank 5, and is separated from the air in the discharge chamber 29 of the compressor 21.
8, is sucked into the second pump 3 via a passage 45, and is returned to the tank 5 via a passage 46. While the compressed air in the tank 5 is taken out from the outlet 60 and consumed, the rotary compressor is in full-load operation, the blockage valve 34 fully opens the through hole 33, and the flow control valve 8 is operated with a sufficient amount of air. The area of the internal passage is adjusted to be large so as to supply oil to the compressors 11 and 21. By the way, when the consumption amount of air taken out from the compressed air outlet 60 decreases or no air is taken out at all, the air pressure inside the tank 5 increases, and when this reaches a predetermined adjustment pressure point, the pressure is increased by the action of a pressure adjustment valve (not shown). The pressure in the chamber 38 rises above the pressure in the pressure chamber 37, which is inflowed through a pressure reducing valve (not shown), and the blockage valve 34 is moved toward the through hole 33;
The air intake is stopped by closing the through hole 33. In synchronization with the movement of the blockage valve 34, the movable valve body built into the flow rate regulating valve 8 is moved by the action of the pressure regulating valve to throttle the internal passage within the regulating valve 8 and reduce the amount of oil supplied to the passage 41. reduce the load and enter the no-load operation state. In the no-load operating state, the compressor 11 is operated with zero intake air at the suction port 14, and no heat of compression of the gas is generated. However, since the compressors 11 and 21 are operated at constant speed, oil lubricates the rotating parts. The required amount is discharged into the compression chambers 17, 27. At this time, the amount of oil delivered by the flow rate regulating valve 8 is set to be less than half of that during full load operation. This lubricating oil is sucked from the tank 5 by the first pump 2 through the cooler 9 and the passage 42, and is discharged into the passage 40, and is discharged into the flow rate regulating valve 8.
However, when the internal passage of the flow rate adjustment valve 8 is narrowed and the hydraulic pressure in the passage 40 increases, the relief valve 50 is activated, and excess pressure oil above a predetermined pressure is transferred from the passage 48 to the tank 5 or the cooler. 9 is discharged and recirculated to the upstream side. Therefore, even during low-load or no-load operation, the tank 5, cooler 9, and passage 4
2, the same amount of oil as at full load circulates and flows, preventing the oil temperature from rising. Furthermore, even if the pressure on the discharge side of the first pump 2 increases during no-load operation, due to the presence of the relief valve 50, the pressure on the discharge side will not increase above a certain value; rather, as shown in FIG. Unlike the liquid supply circuit, the suction side is not in a vacuum state, so there is no need to worry about abnormal noise, and therefore it is sufficient to select or design according to the amount of oil supplied during full load operation of the compressor. . Even during no-load operation, oil is supplied to the compression chambers 17 and 27 of the compressor via the flow rate adjustment valve 8 and is discharged to the discharge port 25 of the second stage compressor 21. Since the air in the discharge chamber and the oil separated from the air are discharged and removed, the non-return valve 4 is closed, and the oil is sucked into the second pump 3 from the drain 28 through the passage 45, and then through the passage 46 into the tank 5. The oil is refluxed to the oil reflux port 47. That is, the second pump 3 is a load reducing device 31.
Even after the closing valve 34 closes the passage hole 33 and the compressed air is no longer discharged to the discharge port 25, air and oil are discharged and removed from the drain 28, so that the air and oil in the discharge chamber 29 are removed. Since the pressure is significantly reduced, the pressure difference between the compressor suction port 14 and the discharge port 25 is reduced, and the back pressure acting on the rotors 12, 22 is removed, the power consumption of the compressor is 20%.
% or less. However, in the case of a compressor that does not include the second pump 3, the load reduction device 31 operates and the blockage valve 34 closes the through hole 33.
When the valve 34 is closed, the pressure in the discharge chamber 29 is maintained at the pressure at the time of operation of the load reduction device, and the pressure on the suction side of the compressor becomes negative pressure when the closing valve 34 closes the passage hole 33. The machine is operated with a pressure difference (back pressure) greater than the pressure inside the discharge chamber acting on the rotors 12 and 22 of the machine. In such a no-load operating state, if the closing valve 34 is not fully seated and even a small amount of air is sucked into the compression chambers 17, 27 from the through hole 33 of the load reduction device 31, the compressed air and Lubricating oil superheated by the heat of compression of the air is discharged into the discharge chamber 29, and if this state continues, the temperature of the lubricating oil in the tank 5 will normally rise. Excess oil is returned to the tank via the valve 50, and the same amount of oil as at full load is circulated to the cooler 9 via the passages 48 and 42, causing an increase in the temperature of the lubricating oil. Never. [Effects of the Invention] As described in detail above, the present invention provides a rotor that is driven by a prime mover and is rotatable in a compression chamber of a casing, a pump that is rotationally driven while the rotor is rotating, and a discharge port of the pump. a passage connected to the compression chamber for supplying cooling, lubricating and sealing liquid discharged by the pump to the compression chamber; and a tank storing gas and liquid discharged from the casing and supplied via the non-return valve; a load reduction device that adjusts the opening of the suction port of the compression chamber according to the internal pressure of the tank; and a flow rate adjustment that adjusts the flow rate of liquid in synchronization with the adjustment of the opening of the suction port of the compression chamber by the load reduction device. In a rotary compressor provided with a valve, a passage for supplying liquid to the compression chamber is connected to a discharge port of the pump via the flow rate adjustment valve, and an inlet port of the pump and a liquid discharge port of the tank are connected. are connected via a cooler, and the passage between the outlet of the pump and the liquid return port of the tank or the liquid outlet of the tank and the cooler is connected to the outlet of the pump, and the pressure at the outlet of the pump is When the pressure exceeds a predetermined value, the load reduction device closes the compression chamber suction port of the compressor, resulting in no-load operation. , the flow rate adjustment valve adjusts the flow rate by means such as narrowing down the liquid circulation area in synchronization with the closure of the suction port, and reduces the amount of liquid supplied to the compression chamber of the compressor to the minimum amount necessary for lubrication, etc. When the liquid pressure on the discharge side of the pump increases accordingly, the excess pressure liquid that exceeds a predetermined value is returned to the tank or to the downstream side immediately after the liquid outlet of the tank, thereby increasing the pressure of the pump. Since the same amount of liquid is circulated as during full load operation, it prevents the temperature of the liquid from rising even during no-load operation, prevents the temperature of the discharge chamber from rising, and eliminates the cause of abnormal noise in the pump. It has been removed. To ensure circulation of the same amount of liquid as at full load,
If the suction port in the load reduction device is incompletely blocked for some reason, the pump compresses a small amount of intake air in the compression chamber while setting the flow rate of the liquid to the necessary minimum, similar to the no-load operation state. This can be said to be extremely effective in preventing an increase in the temperature of the liquid and an accompanying increase in the temperature of the discharge chamber in an unexpected situation. Although the embodiment of the present invention uses an induction-type constant-speed rotary motor, such a motor is of a commonly used type and is inexpensive. ON/OFF only in two load states: operating state and no-load operating state.
This is suitable for use in rotary compressors that operate in the off system. In such a rotary compressor, on-off control is repeated in the case of an intermediate load state, but the closing valve of the load reduction device is fully opened by the action of the pressure regulating valve (not shown). By adjusting the amount of intake air by adjusting the amount of intake air between the two positions of fully closing the intake vent and fully closing the intake vent, the It is possible to take an intermediate load state. Further, in the present invention, when it is desired to change the rotation of the compressor according to the load operating state, a variable rotation type motor is used as the motor, and the blockage valve of the load reduction device, the flow rate adjustment valve, or the pressure (not shown) is used. In conjunction with the operation of the regulating valve, the rotational speed can be controlled to be the highest during full-load operation, and the rotational speed to be the lowest during no-load operation. Furthermore, in the present invention, an internal combustion engine can be used as the prime mover in addition to a motor. When using an internal combustion engine, the throttle is controlled at the maximum torque rotation speed during full-load operation, and at idling rotation speed during no-load operation, in conjunction with the blockage valve, flow control valve, or pressure control valve of the load reduction device. It is a good idea to do this. An example of the effects of the present invention will be shown below. Actual discharge volume 5.6m ² /min driven by an electric motor with an output of 37KW
It is a single stage screw type compressor with compressor shaft input of 37KW at full load, circulating oil flow rate of 50/min, input heat amount of 31300KCal/hr, cooler inlet oil temperature 85℃, cooler outlet oil temperature 60℃, and discharge air temperature. The data when the embodiment of the present invention shown in FIG. 1 is applied to a compressor with specifications of 85°C and the data of the comparative example shown in FIG.
When the load reduction device operates and fully closes the intake air to the cylinder and reduces the compressor shaft input to 20% (7.4KW) (circulating oil amount 25/min), and the load reduction device does not block the intake air. The table below compares the case where the compressor is completely compressed and the compressor shaft input is 70% (25.9KW).

[Table] As is clear from the above table, in the case of the comparative example shown in Figure 2, the cooler heat dissipation capacity also decreases compared to when operating at full load, and in particular, the intake air is compressed due to incomplete air intake blockage of the load reduction device. In contrast, in the embodiment of the present invention, the cooler discharge capacity remains the same as during full load operation, and both the oil temperature and the discharge air temperature can be kept low. I understand. Although a screw type compressor has been described as the above embodiment, the present invention is not limited to the screw type, and can be applied to other types of rotary compressors such as vane type and worm type. In addition to the methods described in this book, any other suitable method may be employed as long as it does not contradict the purpose of the present invention.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows a comparative example of a conventional device for comparison. In the figure, 1 is a motor, 11 and 21 are compressors, 1
2, 22 are its rotors, 13, 23 are its casings, 14, 24 are its suction ports, 15, 25 are its discharge ports, 16, 26 are its oil holes, 17, 27
is its compression chamber, 2 and 3 are pumps, 5 is tank, 8
9 is a flow regulating valve, 9 is a cooler, 31 is a load reduction device, 33 is a through hole thereof, 34 is a closing valve thereof, and 50 is a relief valve.

Claims (1)

[Claims] 1. A compressor casing, a compressor rotor driven by a prime mover and rotatable within the compression chamber of the casing, a pump that is rotationally driven while the rotor is rotating, and a compressor rotor that is connected to a discharge port of the pump and is connected to the compression chamber. A passage for supplying liquid for cooling, lubricating and sealing the compressor discharged by the pump, a tank for storing the gas and liquid discharged from the casing and supplied via the non-return valve, and an internal pressure of the tank. a load reduction device that adjusts the opening degree of the suction port of the compression chamber according to the load reduction device; and a flow rate that adjusts the flow rate of the liquid supplied to the compression chamber in synchronization with the adjustment of the opening degree of the suction port of the compression chamber by the load reduction device. In a rotary compressor provided with a regulating valve, a passage for supplying liquid to the compression chamber is connected to a discharge port of the pump via the flow rate regulating valve, and an inlet port of the pump and a liquid discharge port of the tank. are connected via a cooler, and either one of the liquid return port of the tank and the passage between the liquid discharge port of the tank and the cooler is connected to the discharge port of the pump. 1. A rotary compressor, characterized in that the rotary compressor is connected via a relief valve that causes excess pressure liquid to flow back to the tank side when the pressure exceeds a predetermined value.