KR20210068978A - Air compressing system - Google Patents

Abstract

An objective of the present invention is to prevent lubricating oil flowing back to a compressor body from being excessively cooled. To achieve the objective, an air compression system includes: an oil separator (20) separating oil from compressed air discharged from an oil-cooling type compressor body (11); a return oil line (L30) connected to a liquefication part of the oil separator (20) and returning lubricating oil (O1) after gas-liquid separation to the compressor body (11); a water cooling type oil cooler (30) installed on the return oil line (L30); a water-feeding switching means installed on a coolant line (L50) of the water cooling type coil cooler (30) and switching a water-feeding execution state and a water-feeding stoppage state with respect to the water cooling type oil cooler (30); a first bypass line (L31) connected to the return oil line (L30) and bypassing the lubricating oil (O1) to an air-cooling type oil cooler (40); and a bypass valve (51) opening and closing the first bypass line (L31). A control part (200) opens the bypass valve (51) when the water-feeding switching means is in the water-feeding execution state, and closes the bypass valve (51) when the water-feeding switching means is in the water-feeding stoppage state.

Description

AIR COMPRESSING SYSTEM

The present invention relates to an air compression system.

In oil-cooled air compressors widely used in industry, 100% of the power supplied is converted into thermal energy (mainly compression heat and friction heat). In screw compressors, 15 to 20% of heat goes to the compressed air discharged from the compressor body and 75 to 70% of heat goes to the lubricating oil circulated in the compressor body. emitted by the cooler.

In recent years, many business establishments, such as factories, are making efforts to convert the auxiliary equipment of various facilities into highly energy-efficient ones for the purpose of reducing the emission of carbon dioxide which is a greenhouse gas. Then, as shown in patent document 1, the cogeneration type air compression system which can manufacture hot water by heat recovery simultaneously with manufacture of compressed air is proposed.

Japanese Patent Laid-Open No. 2012-67743

In the air compression system described in Patent Document 1, a water-cooled oil cooler for heat recovery (exhaust heat recovery heat exchanger 10) and an air-cooled oil cooler for heat dissipation (air-cooled heat exchanger 13) are installed in series in a lubricating oil conveyance line. and the rotation speed of the cooling fan of the air-cooled oil cooler is controlled so that the temperature of the compressed air discharged from the compressor body is within a predetermined range. Further, on the upstream side of the water-cooled oil cooler, a temperature control valve for directly conveying a part of the lubricating oil separated from the compressed air to the inlet side of the compressor body is provided.

In the air compression system having such a configuration, since the cooling fan is usually controlled to a minimum rotation speed or higher during operation of the compressor body, there is a problem that the lubricating oil after heat recovery in the water-cooled oil cooler is easily cooled more than necessary in the air-cooled oil cooler. If excessive cooling of the lubricating oil proceeds, the amount of return oil through the temperature control valve increases and the amount of oil supplied to the water-cooled oil cooler decreases. There are concerns.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent excessive cooling of lubricating oil returning to a compressor body in an air compression system configured to recover heat from lubricating oil.

The present invention provides an oil-cooled compressor body, a first air supply line through which compressed air discharged from the compressor main body flows, an oil separator connected to the first air supply line and separating oil from compressed air; a second air supply line connected to the gas phase part and through which compressed air after gas-liquid separation flows; a return oil line connected to the liquid phase part of the oil separator and conveying the lubricating oil after gas-liquid separation to the intake side of the compressor body; A water-cooled oil cooler for heat recovery installed in a line, a cooling water line for circulating cooling water to the water-cooled oil cooler, and a water flow switching means installed in the cooling water line to switch between a water flow execution state and a water flow stop state for the water-cooled oil cooler an air-cooled oil cooler for heat dissipation provided in the return oil line downstream of the water-cooled oil cooler, and a first bypass line connected to the return oil line and bypassing the lubricating oil with respect to the air-cooled oil cooler; a bypass valve for opening and closing the first bypass line; a second bypass line connected to the return oil line and bypassing the lubricating oil with respect to the water-cooled oil cooler and the air-cooled oil cooler; A temperature control valve for adjusting a flow rate ratio of oil supply to the water-cooled oil cooler and oil supply to the second bypass line according to the temperature of the lubricating oil, and control means for controlling the water flow switching means and the bypass valve, The control means is related to an air compression system that controls to open the bypass valve when the water flow switching means is in a water flow execution state and close the bypass valve when the water flow switching means is in a water flow stop status. .

In addition, the bypass valve is installed in the first bypass line, and the return oil line and the first bypass line have an outlet pipe connected to an upstream end of the water-cooled oil cooler, and a downstream end of the return oil line and the first bypass line. A straight pipe to which the inlet port of the bypass valve is connected, a T-pipe for branching mounted on the middle part of the straight pipe, and a communication pipe for communicating the inlet pipe of the air-cooled oil cooler and the branch port of the T-pipe It is preferable to include.

In addition, a shut-off valve that opens and closes the return oil line on the upstream side of the air-cooled oil cooler and downstream of the connection point of the first bypass line, and controls the water flow switching means, the bypass valve and the shut-off valve a control means is provided, wherein the control means opens the bypass valve and closes the shut-off valve when the water flow switching means is in a water flow execution state, and closes the shutoff valve when the water flow switching means is in a water flow stop status. It is preferable to close the pass valve and open the shut-off valve.

Moreover, it is preferable that the said water-cooled oil cooler is a plate type heat exchanger which laminated|stacked the heat transfer plates made of titanium.

In addition, a water-cooled air cooler for heat recovery provided in the second air supply line and an air-cooled air cooler for heat dissipation provided on a downstream side of the water-cooled air cooler, wherein the cooling water line includes the water-cooled oil cooler and the water-cooled air cooler It is preferable that the cooling water is circulated in series or in parallel with respect to each other, and the water flow switching means is a means for switching the water-cooled oil cooler and the water-cooled air cooler to the same water flow state.

In addition, a tap temperature sensor for detecting a tap temperature of the cooling water after passing through the water-cooled oil cooler is provided, the water passing switching means is configured to be able to adjust the water passing flow rate in addition to switching the water passing state, and the control means is the water passing It is preferable to adjust the water flow rate so that the tapping temperature detected by the tapping temperature sensor becomes the target tapping temperature while the switching means is switched to the water passing execution state.

In addition, the target tapping temperature includes a first target tapping temperature and a second target tapping temperature lower than the first target tapping temperature, and the control means is configured to control any one of the first target tapping temperature and the second target tapping temperature. It is preferable to have a target tapping temperature setting means selectable from one.

In addition, a lubricating oil temperature sensor for detecting the temperature of the lubricating oil discharged together with the compressed air from the compressor body or the temperature of the lubricating oil after gas-liquid separation in the oil separator is provided, wherein the water passing switching means is provided in addition to switching of the water passing state Preferably, the flow rate is adjustable, and the control means adjusts the water flow rate so that the temperature detected by the lubricating oil temperature sensor becomes the target oil temperature while the water flow switching means is switched to the water passing execution state.

In addition, the target oil temperature includes a first target oil temperature and a second target oil temperature lower than the first target oil temperature, and the control means is configured to select any one of the first target oil temperature and the second target oil temperature. It is desirable to have means for setting the target oil temperature, one of which is selectable.

Preferably, the control means adjusts the water flow rate by the water flow switching means within the range of the upper limit water flow rate and the lower limit water flow rate.

Preferably, the control means adjusts the degree of closing or opening of the bypass valve when a predetermined time has elapsed in a state where the detection temperature of the lubricating oil temperature sensor exceeds the first target oil temperature.

(Effects of the Invention)

According to the present invention, it is possible to prevent excessive cooling of the lubricating oil returning to the compressor body in the air compression system configured to recover heat from the lubricating oil.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the air compression system by 1st Embodiment of this invention.
Fig. 2 is a block diagram showing a control unit of the embodiment.
3 is a flowchart of water flow switching control and bypass valve control in the embodiment.
Fig. 4A is a flowchart of the constant control of the tapping temperature in the embodiment.
Fig. 4B is a flowchart of the discharge temperature constant control in the above embodiment.
It is a figure which shows typically the modification of the air compression system of the said embodiment.
6 is a diagram schematically showing an air compression system according to a second embodiment of the present invention.
It is a figure which shows typically the modification of the air compression system of the said embodiment.

1 : is a figure which shows typically the structure of the air compression system 1 which concerns on 1st Embodiment. As shown in FIG. 1 , the air compression system 1 includes a compressor 10 , an oil separator 20 , a water-cooled oil cooler 30 , an air-cooled oil cooler 40 , and a control unit 200 as main components. provided as

And the air compression system 1 of this embodiment is connected to the 1st air supply line L10 which flows the compressed air discharged from the compressor 10 into the oil separator 20, and the gas phase part of the oil separator 20. The air-cooled oil cooler in the second air supply line L20, the return oil line L30 connected to the liquid phase of the oil separator 20 to return lubricating oil to the compressor 10, and the return oil line L30 A first bypass line L31 that bypasses 40 and a second bypass line L32 that bypasses the water-cooled oil cooler 30 and the air-cooled oil cooler 40 in the return oil line L30 to provide In addition, an air introduction line L40 for introducing air into the compressor 10 is provided.

In addition, the "line" in this specification is a generic term for the line which can distribute|circulate fluid, such as a flow path, a path|route, and a pipeline.

The compressor main body 11 of the compressor 10 has an air compression mechanism (not shown), such as a screw mechanism, a scroll mechanism, and a rotary mechanism. By driving the motor 12 connected to the drive shaft of the air compression mechanism of the compressor main body 11, external air is sucked and adiabatically compressed to generate compressed air A0, and this is discharged. The compressor main body 11 of this embodiment is an oil-cooling type, and by introduce|transducing the lubricating oil O1 into an air compression mechanism with supply air, it cools an air compression mechanism, ie, removes compression heat. In addition, the motor 12 may employ various driving methods such as an electric driving motor or a steam driving motor.

A first air supply line L10 through which the compressed air A0 discharged from the compressor main body 11 flows is connected to the discharge port of the compressor main body 11 . An oil separator 20 as a separator for separating lubricating oil from compressed air is connected to the downstream side of the first air supply line L10.

A second air supply line L20 through which the compressed air A1 after gas-liquid separation flows is connected to the gas phase portion of the oil separator 20 . On the other hand, the liquid phase portion of the oil separator 20 is connected to a return oil line L30 for conveying the lubricating oil O1 after gas-liquid separation to the intake side of the compressor body 11 and reintroducing it into the air compression mechanism.

A lubricating oil temperature sensor 21 for measuring the lubricating oil temperature To of the lubricating oil O1 after gas-liquid separation is provided in the liquid phase of the oil separator 20 . In addition, the lubricating oil temperature sensor 21 is a sensor for measuring the lubricating oil temperature To, and detects the temperature of the lubricating oil O1 before gas-liquid separation discharged from the compressor body 11 (that is, the temperature of the compressed air A0). It may be good to do For example, the arrangement position of the lubricating oil temperature sensor 21 is from the discharge port of the compressor body 11 to the oil separator 20 (gas phase or liquid phase) to the inlet of the water-cooled oil cooler 30. L10) or return oil line (L30). However, in consideration of stable measurement and appropriate control, the lubricant temperature sensor 21 is a return oil line (L30) from the liquid phase of the oil separator 20 or the liquid phase of the oil separator 20 to the inlet of the water-cooled oil cooler 30. It is preferable to place it in

The return oil line L30 is provided with a temperature control valve 53, a water-cooled oil cooler 30 for heat recovery, and an air-cooled oil cooler 40 for heat dissipation, in order from the upstream side.

A second bypass line (L32) for bypassing the lubricating oil (O1) with respect to the water-cooled oil cooler (30) and the air-cooled oil cooler (40) is connected to the branch port of the three-way valve constituting the temperature control valve (53). have. The temperature control valve 53 adjusts the flow rate ratio of the oil supply to the water cooling oil cooler 30 and the oil supply to the second bypass line L32 according to the lubricating oil temperature of the lubricating oil O1 after gas-liquid separation in the oil separator 20. .

As the temperature detection/drive method applicable to the temperature control valve 53 , a thermosensitive tube type, a wax type, a bimetal type, or the like can be exemplified. In addition, as a valve structure applicable to the temperature control valve 53, a 2-way or 3-way slide valve, a 3-way ball valve, a 3-way plug valve, etc. can be illustrated. In addition, in the case of a 3-way valve, as shown in FIG. 1, it is arrange|positioned at the branch part of the 2nd bypass line. In the case of a two-way valve, it is disposed in the middle of the second bypass line. Alternatively, two two-way valves may be used to arrange the intermediate portion of the second bypass line L32 and the downstream side of the branch portion of the second bypass line in the return oil line L30.

The water cooling oil cooler 30 is a heat exchanger for recovering compression heat of the lubricating oil O1 flowing through the return oil line L30. A cooling water line L50 through which the cooling water W1 flows is connected to the water cooling oil cooler 30 . The cooling water line L50 is the primary side line L51 through which the cooling water W1 before being heated in the water-cooled oil cooler 30 flows, and the cooling water after being heated in the water-cooled oil cooler 30 (hot water W2). It has a secondary side line (L52) that flows.

Here, the water-cooled oil cooler 30 is provided as a heat exchanger for producing hot water W2 from the cooling water W1 by performing heat exchange between the cooling water W1 and the high-temperature lubricating oil O1. As the water-cooled oil cooler 30, for example, a plate heat exchanger can be employed. Preferably, a plate-type heat exchanger in which heat transfer plates made of titanium are laminated are employed. In such a heat exchanger, even if the cooling water W1 supplied to the water-cooled oil cooler 30 contains oxidizing agents such as residual chlorine or corrosive ions such as chloride ions, it occurs on the heat transfer surface or the bonding surface of the water-cooled oil cooler 30 . High-temperature corrosion can be suppressed.

A water supply pump 71 , a water treatment device 72 , and a flow rate sensor 73 are installed in the primary side line L51 of the cooling water line L50 in order from the upstream side. In addition, in the secondary side line L52 of the cooling water line L50, a flow rate control valve 74 and a hot water temperature sensor 75 are provided in order from the upstream side.

The water supply pump 71 and the flow control valve 74 are electrically connected to the control part 200, and are driven by the command signal from the control part 200. As shown in FIG. The water treatment apparatus 72 performs a process, such as removal of an impurity. The water treatment device 72 includes, for example, a water softening device, a water supply strainer, and the like. The flow rate sensor 73 detects the flow rate of the cooling water W1. The water flow rate detected by the flow rate sensor 73 is transmitted to the control unit 200 . The tap temperature sensor 75 detects the tap temperature Tw of the coolant after passing through the water-cooled oil cooler 30 , that is, the hot water W2 heated by the water-cooled oil cooler 30 . The tapping temperature Tw detected by the tapping temperature sensor 75 is transmitted to the controller 200 .

The water supply pump 71 and the flow rate regulating valve 74 of this embodiment function as water flow switching means for switching the water flow execution state and the water flow stop state to the water cooling oil cooler 30 . In addition, this water passing switching means also has a water passing flow rate adjustment function for adjusting the water passing flow rate to the water cooling oil cooler 30 .

For example, the water flow switching means capable of adjusting the flow rate may be realized by using the water supply pump 71 with a fixed drive frequency and the flow rate control valve 74 together. For example, in this case, the flow rate of the cooling water W1 is adjusted by adjusting the valve opening degree using a proportional control valve (electric or electromagnetic) as the flow rate control valve 74 .

In addition, the water flow switching means capable of adjusting the flow rate may be realized by a water supply pump (inverter drive pump) 71 having a variable drive frequency. In this case, the feed water pump 71 is electrically connected to the control unit 200 via an inverter (not shown). The inverter is an electric circuit that supplies the frequency-converted driving power to the feed water pump 71 , and outputs the drive power of the drive frequency corresponding to the frequency designation signal to the feed water pump 71 . In addition, in the case of the aspect which adjusts the water supply flow volume by the water supply pump 71, installation of the flow rate control valve 74 can also be abbreviate|omitted. Alternatively, an opening/closing valve that only opens and closes the valve may be provided in place of the flow control valve 74 to stop the water supply pump 71 by this.

The hot water W2 after being heated by the water-cooled oil cooler 30 is supplied to the hot water demand place through the secondary side line L52 of the cooling water line L50.

Thus, in the air compression system 1 of this embodiment, the hot water W2 is manufactured from the cooling water W1 by recovering the compression heat generated by the compressor 10 in the water-cooled oil cooler 30, and this warm water W2 is converted into hot water. We can supply where demand is.

On the downstream side of the water-cooled oil cooler 30 in the return oil line L30, an air-cooled oil cooler 40 for heat dissipation is provided. The air-cooled oil cooler 40 includes a heat exchanger 41 (a heat exchange core made of an aggregate such as plate fins and fin tubes), a cooling fan 42 , and a fan motor 43 for rotating the cooling fan 42 . to provide By rotating the cooling fan 42, heat exchange is performed between the air blown by the cooling fan 42 and the lubricating oil O1 flowing through the inside of the heat exchanger 41 to a temperature suitable for cooling the compressor body 11. of lubricating oil (O1) is produced.

In addition, an aspect in which other parts of the air compression system 1 are simultaneously cooled (eg, control box) or ventilated (eg, inside a housing) by the cooling fan 42 may be adopted. In this case, it is normal that the cooling fan 42 is controlled to the minimum rotation speed or more while the compressor main body 11 is in operation.

The lubricating oil O1 circulated through the water-cooled oil cooler 30 and the air-cooled oil cooler 40 is returned to the inside of the compressor body 11 again through the return oil line L30.

A bypass branch 60 is formed between the water-cooled oil cooler 30 for heat recovery and the air-cooled oil cooler 40 for heat dissipation in the return oil line L30, and the bypass branch 60 ), a first bypass line L31 for bypassing the lubricating oil O1 with respect to the air-cooled oil cooler 40 is connected. In addition, a bypass valve 51 for opening and closing the first bypass line L31 is installed in the first bypass line L31.

The bypass branch 60 is configured as a part of the return oil line L30 and the first bypass line L31 , and includes a straight pipe 61 , a T-pipe 62 , and a communication pipe 63 . be prepared As for the straight pipe 61, the outlet pipe 30A of the water-cooled oil cooler 30 is connected to the upstream end part, and the inlet port 51A of the bypass valve 51 is connected to the downstream end part. The T-pipe 62 is a branching pipe attached to the middle part of the straight pipe 61 . The communication pipe 63 communicates with the inlet pipe 40A of the air-cooled oil cooler 40 and the branch port 62A of the T-pipe 62 . In addition, 30 A of outlet pipe|tube of the water-cooled oil cooler 30, and the upstream end of the straight pipe 61 may be connected via another pipe.

When the bypass valve 51 is opened, the first flow flowing through the first bypass line L31 among the lubricating oil O1 that has passed through the water-cooled oil cooler 30 passes through the bypass valve through the straight pipe 61 . Since the oil is supplied to the valve (51), a relatively small friction loss in the process of passing through the bypass valve (51) is only received in the valve chamber. On the other hand, since the second flow flowing through the return oil line L30 is supplied with oil to the air-cooled oil cooler 40 through the T-pipe 62, it receives a branch loss from the T-pipe 62 and the air-cooled oil cooler 40. A relatively large frictional loss is received in the air-cooled oil cooler 40 in the process of passing through the air-cooled oil cooler 40 . Therefore, the flow rate ratio of the lubricating oil O1 becomes "first flow > second flow", and most of the lubricating oil O1 flows through the 1st bypass line L31 side. Thereby, in preventing excessive cooling of the lubricating oil O1 refluxing to the compressor body 11, the purpose can be achieved inexpensively only by adjusting the pipe resistance without installing a shut-off valve on the air-cooled oil cooler 40 side. can

Next, the control part 200 of the air compression system 1 of this embodiment is demonstrated. 2 is a block diagram of the control unit 200 of the air compression system 1 of the present embodiment. The control unit 200 (control unit) includes a water flow switching control unit 210 , a bypass valve control unit 220 , a water flow rate control unit 230 , and a target tapping temperature setting unit 240 (target tapping temperature setting unit) and , a tapping temperature acquiring unit 250 , a target oil temperature setting unit 260 (target oil temperature setting means), a lubricating oil temperature acquiring unit 270 , and a storage unit 290 .

[Water flow switching control]

The water passing switching control unit 210 performs switching control of the water passing switching means in the water passing execution state and switching control in the water passing stopping state. The switching of the water flow state may be performed by switching the open/closed state of the flow rate control valve 74 , or may be performed by switching the operation/stop state of the water supply pump 71 .

In addition, the determination of switching between the water passing execution state and the water passing stop state can be performed based on the water level information of the hot water storage tank (not shown) connected to the secondary side line L52. For example, when the water level in the hot water storage tank falls to a predetermined water reduction water level (hot water supply start water level), it is determined as the switching timing from the water passing stop state to the water passing execution state. Conversely, when the water level in the hot water storage tank rises to a predetermined full water level (hot water supply stop water level), it is determined as the switching timing from the water passing execution state to the water passing stop state.

[Basics of Bypass Valve Control]

The bypass valve control unit 220 performs opening/closing control of the bypass valve 51 . Specifically, the bypass valve control unit 220 opens the bypass valve 51 when the water flow switching means is in the water flow execution state, and closes the bypass valve 51 when the water flow switching means is in the water flow stop state. .

When heat recovery is performed by flowing cooling water W1 into the water-cooled oil cooler 30 in this way, since the bypass valve 51 is configured to open, most (eg, 90% or more) of the lubricating oil O1 is the first The amount of oil supplied to the air-cooled oil cooler 40 flowing through the bypass line L31 is slightly (for example, less than 10%). Since the influence of cooling in the air-cooled oil cooler 40 is minimized in the lubricating oil O1 after merging, the lubricating oil O1 refluxing to the compressor body 11 is maintained in an appropriate temperature range without excessive cooling. . Thereby, the required heat recovery amount can be ensured without reducing the oil supply amount to the water-cooled oil cooler.

In addition, when the bypass valve 51 is opened, the coolant W1 supplied to the water-cooled oil cooler 30 is low temperature or the lubricating oil O1 delivered from the oil separator 20 is When it cools too much, a part of lubricating oil O1 is bypassed with respect to the water-cooled oil cooler 30 by the temperature control valve 53. As shown in FIG. Thereby, the lubricating oil O1 conveyed to the compressor main body 11 can be maintained in the appropriate temperature range while heat recovery is actively performed by the water-cooled oil cooler 30. As shown in FIG.

In addition, the opening and closing of the bypass valve 51 may be an immediate operation following the switching of the water flow execution state and the water flow stop state, or may be a gradual operation.

In the case of immediate operation, the bypass valve 51 is opened at the same time as the water passing switching means is switched to the water passing execution state or after a delay time of about several seconds. In addition, the bypass valve 51 is closed at the same time that the water flow switching means is switched to the water flow stop state or after a delay time of about several seconds.

In the case of gradual operation, the bypass valve 51 is opened when the water passing switching means is switched to the water passing execution state and a predetermined condition (for example, the temperature condition of the cooling water, etc.) is satisfied. In addition, when the water flow switching means is switched to the water flow stop state and a predetermined condition (for example, a flow rate condition of cooling water, etc.) is satisfied, the bypass valve 51 is closed.

[Outline of water flow control]

While the water flow control unit 230 is switching the water passing switching means to the water passing execution state, based on the relationship between the target tapping temperature (Twt) and the tapping temperature (Tw), or the target oil temperature (Tot) and the lubricating oil temperature (To) control to adjust the water flow rate. The water flow rate adjustment can be performed by frequency control of the water supply pump 71 or valve opening degree control of the flow rate control valve 74 .

The target tapping temperature setting unit 240 sets the target tapping temperature Twt of the hot water W2. A single set value may be used as the target tapping temperature Twt, and the first target tapping temperature Twt1 (upper limit tapping temperature) and the second target tapping temperature Twt2 (lower limit tapping temperature) lower than this value are 2 You may use the setting values of dogs. In this case, the target tapping temperature setting unit 240 is configured to select one of the first target tapping temperature Twt1 and the second target tapping temperature Twt2.

The tapping temperature acquisition unit 250 acquires the tapping temperature Tw detected by the tapping temperature sensor 75 .

The target oil temperature setting unit 260 sets the target oil temperature Tot of the lubricating oil O1 (target temperature for the high temperature lubricating oil before heat recovery). A single set value may be used as the target oil temperature Tot, and a first target oil temperature Tot1 (upper limit oil temperature) and a second target oil temperature Tot2 (lower limit oil temperature) lower than this value are 2 You may use the setting values of dogs. In this case, the target oil temperature setting unit 260 is configured to select one of the first target oil temperature Tot1 and the second target oil temperature Tot2.

The lubricating oil temperature acquisition unit 270 acquires the lubricating oil temperature To detected by the lubricating oil temperature sensor 21 .

[Details of water flow control: constant control of hot water temperature]

As described above, while the water passing switching means is switched to the water passing execution state, the water passing flow rate control unit 230 performs control for adjusting the water passing flow rate based on the relationship between the target hot water temperature Twt and the hot water temperature Tw. Specifically, while the water passing switching means is switched to the water passing execution state, the valve opening degree of the flow rate control valve 74 is adjusted so that the tapping temperature Tw detected by the tapping temperature sensor 75 becomes the target tapping temperature Twt, or The drive frequency of the feed water pump 71 is adjusted.

In the constant tapping temperature control, for example, the flow rate is adjusted so that the tapping temperature Tw detected by the tapping temperature sensor 75 is used as a feedback value to converge the tapping temperature Tw to the target tapping temperature Twt. It is preferable to employ feedback control for adjusting the valve opening degree of the valve 74 or the driving frequency of the feed water pump 71 . For the feedback control, in addition to the proportional control (P control), a calculation algorithm of the manipulated variable in which the integral control (I control) and/or the differential control (D control) are combined can be employed.

Here, a case where two set values of the first target tapping temperature Twt1 and the second target tapping temperature Twt2 are used separately will be described in detail.

The first target tapping temperature Twt1 (upper-limit tapping temperature, for example, 65° C.) is a set value for preventing boiling of the hot water W2 inside the water-cooled oil cooler 30 or local material overheating. By adjusting the water flow rate so that the tapping temperature Tw detected by the tapping temperature sensor 75 converges to the first target tapping temperature Twt1, thermal stress generated in the heat transfer surface of the water-cooled oil cooler 30 or the member junction is relieved. Thus, stable heat recovery can be realized without causing damage due to material deterioration.

The second target hot water temperature Twt2 (lower limit hot water temperature, for example, 55° C.) is a set value for making the hot water using device exhibit desired/desired performance. By adjusting the water flow rate so that the tapping temperature Tw detected by the tapping temperature sensor 75 converges to the second target tapping temperature Twt2, the fuel consumption of the steam boiler can be effectively reduced when the hot water W2 is used for boiler feedwater. It can contribute to energy saving by reducing

The first target tapping temperature Twt1 and the second target tapping temperature Twt2 may be configured to be manually selected by the target tapping temperature setting unit 240 through an operation panel or the like. For example, a first target hot water temperature (Twt1) is selected for a hot water demand place where hot water supply temperature is more important than hot water supply flow rate, and a second target hot water temperature (Twt2) is selected for a hot water demand place where hot water supply flow rate is more important than hot water supply temperature. select

In addition, the first target tapping temperature Twt1 and the second target tapping temperature Twt2 may be configured to be automatically selected as a function of the target tapping temperature setting unit 240 . In addition, at the time of selection, you may make it flow volume adjustment by switching between the constant tap temperature control and the discharge temperature constant control (described later). For example, the target tapping temperature setting unit 240 may perform the first target tapping temperature Twt1 or the second target tapping temperature Twt2 based on a change in the physical amount (temperature, etc.) of the cooling water while executing the discharge temperature constant control. ) is selected. Then, by instructing the water passing flow rate control unit 230 to switch from the constant discharge temperature control to the constant tap temperature control, the deviating of the tap temperature Tw outside the range of the upper limit tap temperature or the lower limit tap temperature is suppressed.

In addition, the water flow control unit 230 may be configured to execute the discharge temperature constant control described below in place of the above-described constant tap temperature control.

In addition, in the water flow control part 230, either one of the constant tap temperature control and the constant discharge temperature control may be performed at all times, or the two controls may be switched according to a predetermined condition.

[Details of water flow control: constant discharge temperature control]

The water flow control unit 230 performs control for adjusting the water flow rate based on the relationship between the target oil temperature Tot and the lubricating oil temperature To while the water flow switching means is switched to the water passing execution state as described above. Specifically, while the water flow switching means is switched to the water flow execution state, the valve opening degree of the flow control valve 74 is adjusted so that the lubricant temperature To detected by the lubricant temperature sensor 21 becomes the target lubricant temperature Tot, or The drive frequency of the feed water pump 71 is adjusted.

In the discharge temperature constant control, for example, using the lubricant temperature To detected by the lubricant temperature sensor 21 as a feedback value, the flow rate adjustment valve 74 to converge the lubricant temperature To to the target oil temperature Tot. It is preferable to employ feedback control to adjust the valve opening degree of the water pump 71 or the driving frequency of the feed water pump 71 . For the feedback control, in addition to the proportional control (P control), an arithmetic operation algorithm for combining the integral control (I control) and/or the differential control (D control) can be employed.

Here, a case where two set values of the first target oil temperature Tot1 and the second target oil temperature Tot2 are used separately will be described in detail.

The first target oil temperature Tot1 (upper limit oil temperature, for example, 80° C.) is a set value for suppressing high-temperature deterioration (thermal decomposition, oxidation, etc.) of the lubricating oil and additives contained in the lubricating oil. By adjusting the water flow rate to converge the lubricating oil temperature To detected by the lubricating oil temperature sensor 21 to the first target oil temperature Tot1, the lubricant can be used without deterioration until the recommended replacement time of the lubricant manufacturer arrives. can As a result, it is possible to avoid a failure due to poor cooling and lubrication of the compressor main body 11 .

The second target oil temperature Tot2 (lower limit oil temperature, for example, 75° C.) is a set value for suppressing the mixing of condensed water (moisture generated by cooling the sucked wet air to below the dew point temperature) into the lubricating oil. By adjusting the flow rate of the lubricating oil so as to converge the lubricating oil temperature To detected by the lubricating oil temperature sensor 21 to the second target oil temperature Tot2, the lubricating oil does not cause a change in properties. As a result, it is possible to avoid a failure due to poor cooling and lubrication of the compressor main body 11 . In addition, since various oxidizing gases (oxygen gas and carbon dioxide in the air, NOx and SOx flowing into the air from exhaust gas in a factory, etc.) are not dissolved in the condensate, unexpected corrosion of compression mechanisms (screw rotors and bearings, etc.) is avoided. You may.

The first target oil temperature Tot1 and the second target oil temperature Tot2 may be configured to be manually selected by the target oil temperature setting unit 260 through an operation panel or the like. For example, in summer when the coolant supply temperature is relatively high, the lubricating oil after heat recovery tends to be high, so the first target oil temperature Tot1 is selected, and in winter when the coolant supply temperature is relatively low, the lubricating oil after heat recovery is low , so the second target oil temperature Tot2 is selected.

In addition, the first target oil temperature Tot1 and the second target oil temperature Tot2 may be configured to be automatically selected as a function of the target oil temperature setting unit 260 . In addition, at the time of selection, you may make it flow volume adjustment by switching the discharge temperature constant control and the hot water constant control (above). For example, the target oil temperature setting unit 260 may include the first target oil temperature Tot1 or the second target oil temperature Tot2 based on a change in the physical quantity (temperature, etc.) of the lubricating oil when the tapping temperature constant control is being executed. ) is selected. Then, by instructing the water flow control unit 230 to switch from the constant tap temperature control to the constant discharge temperature control, the lubricating oil temperature To is suppressed from deviating outside the range of the upper limit oil temperature or the lower limit oil temperature.

[Details of water flow control: Limitation of water flow rate]

The water flow control unit 230 adjusts the water flow rate by the water flow switching means within the range of the upper limit water flow rate Qw1 and the lower limit water flow rate Qw2 while the hot water constant control or the discharge temperature control is being executed.

The upper limit water flow rate Qw1 is a set value based on the maximum water supply amount per unit time of the water supply pump 71 (water flow switching means) or the maximum use amount per unit time of the hot water use device in the hot water demand place. By setting the upper limit water flow rate Qw1, hot water supply is not performed at an excessive flow rate that lacks a balance with respect to the hot water demand amount. Therefore, it is possible to prevent performance degradation or failure due to overload of water supply equipment (inverter drive pumps, water control pumps, etc.). In addition, since the upper limit water flow rate Qw1 is set in consideration of a state in which the hot water demand amount of the hot water-using device is increased, an unexpected stop of the hot water-using device due to the insufficient amount of hot water is avoided.

The lower limit water flow rate Qw2 is a set value based on the minimum water flow rate per unit time that guarantees the treatment performance of the water treatment device 72 for cooling water reforming installed in the cooling water line L50 (the above-described light water softener, water supply strainer, etc.) to be. By setting the lower limit water flow rate Qw2, the impurity removal/separation capability of the water treatment device 72, that is, the water quality after treatment is guaranteed. Therefore, it is possible to extend the lifespan of not only hot water equipment but also hot water supply pipes in facilities.

In addition, you may use the detection value of the flow rate sensor 73 in adjusting the water flow flow rate within the range of upper limit water flow flow rate Qw1 and lower limit water flow flow rate Qw2. In this case, while monitoring by the flow rate sensor 73, the opening degree of the flow control valve 74 which consists of a proportional control valve is controlled within the range of upper limit water flow flow rate Qw1 and lower limit water flow flow rate Qw2. Alternatively, the driving frequency of the water supply pump 71 is controlled within the range of the upper limit water flow rate Qw1 and the lower limit water flow rate Qw2 while monitoring by the flow rate sensor 73 .

On the other hand, when the flow rate sensor 73 is not used, the upper limit opening degree of the flow control valve 74 comprising a proportional control valve corresponding to the upper limit water flow rate Qw1 and the flow rate adjustment corresponding to the lower limit water flow rate Qw2 You may set the lower limit opening degree of the valve 74 in advance, and you may control the opening degree of the flow control valve 74 within the range of an upper limit opening degree and a lower limit opening degree.

In addition, the upper limit driving frequency of the water supply pump 71 corresponding to the upper limit water flow rate Qw1 and the lower limit driving frequency of the water supply pump 71 corresponding to the lower limit water supply flow rate Qw2 are set in advance, and the upper limit driving frequency and the lower limit driving frequency are set in advance. You may control the drive frequency of the water supply pump 71 within a frequency range.

In addition, even if the lower limit water flow rate Qw2 is reached, the lubricating oil temperature To remains below the lower limit oil temperature Tot2 and falls to the set temperature (for example, 70°C) of the temperature control valve 53 . The regulating valve 53 starts an oil return operation to reduce the amount of oil supplied to the water-cooled oil cooler 30 .

As described above, the water passing flow rate control unit 230 of the present embodiment has a function of controlling for adjusting the water passing flow rate based on the relationship between the target hot water temperature Twt and the tap water temperature Tw, and the target oil temperature Tot and It has a function of performing control for adjusting the water flow rate based on the relationship between the lubricating oil temperature To. As for these hot water constant temperature control function and discharge temperature constant control function, either one of the functions can be selected based on a user's instruction. Alternatively, either function may be automatically selected according to the state of the system (physical quantities of cooling water and/or lubricating oil, etc.).

[Application of Bypass Valve Control 1]

The bypass valve control unit 220 bypasses when a predetermined time elapses in a state where the lubricant temperature To detected by the lubricant temperature sensor 21 exceeds the first target oil temperature Tot1 (upper limit oil temperature). The valve 51 is forcibly closed. For example, (a) when the state in which the lubricating oil temperature (To) becomes 82°C or higher continues for t1 hour, (b) when the state in which the lubricating oil temperature (To) becomes 85°C or higher continues for t2 hours, (c) ) The bypass valve 51 is closed when any one of the conditions is satisfied among the cases where the state in which the lubricant temperature To becomes 90° C. or higher continues for t3 time. As the bypass valve 51 in this example, an open/fully closed 2-position valve (electric or electromagnetic) is used.

As a result, even if the water flow rate of the cooling water W1 is increased to the maximum within the allowable range, when the lubricating oil O1 cannot be sufficiently cooled by the water cooling oil cooler 30 main body, the bypass valve 51 is closed to water cooling. The cooling of the two-step method of the oil cooler 30 and the air-cooled oil cooler 40 is performed. Accordingly, it is possible to reliably lower the lubricating oil O1 to less than the upper limit oil temperature (eg, 80° C.).

[Application of Bypass Valve Control 2]

The bypass valve control unit 220 bypasses when a predetermined time elapses in a state where the lubricant temperature To detected by the lubricant temperature sensor 21 exceeds the first target oil temperature Tot1 (upper limit oil temperature). The degree of opening of the valve 51 is adjusted. For example, when the state in which the lubricant temperature To becomes 82°C or higher continues for t4 hours, the opening degree of the bypass valve 51 is adjusted to 75%, and the lubricant temperature To becomes 85°C or higher. When the state continues for t5 hours, the opening degree of the bypass valve 51 is adjusted to 50%, and when the state in which the lubricating oil temperature To becomes 90° C. or higher continues for t6 hours, the bypass valve 51 Adjust the opening to 25%. As the bypass valve 51 in this example, a proportional control valve (electric type or electromagnetic type) is used.

Accordingly, even if the water flow rate of the cooling water W1 is increased to the maximum within the allowable range, when the lubricant oil O1 cannot be sufficiently cooled by the water cooling oil cooler 30 main body, the opening degree of the bypass valve 51 is adjusted. The cooling of the two-step method of the water-cooled oil cooler 30 and the air-cooled oil cooler 40 is performed by this. In particular, the higher the lubricating oil temperature To, the higher the temperature of the air-cooled oil cooler 40 without reducing the heat recovery amount in the water-cooled oil cooler 30 by setting the degree of opening of the bypass valve 51 to be smaller in stages. You can use the cooling effect. Accordingly, it is possible to reliably lower the lubricating oil O1 to less than the upper limit oil temperature (eg, 80° C.).

In addition, in the applications 1 and 2 described above, as a factor that causes a situation where the lubricating oil temperature To > the first target oil temperature Tot1, the water supply temperature of the cooling water W1 is high and the cooling capacity by water cooling is insufficient. Cases and the like are conceivable.

Therefore, based on the water supply temperature of the cooling water W1 at the time when the bypass valve 51 is closed or when the opening degree is adjusted, the water supply temperature has decreased by a predetermined temperature difference (for example, 5 ° C. minutes) from this reference temperature. In this case, it may be judged that the cooling performance of the water-cooled oil cooler 30 is restored, and control may be performed to open the bypass valve 51 again. In this case, a water supply temperature sensor (not shown) is installed in the primary side line L51 of the cooling water line L50.

In addition, when the load factor decreases by a predetermined load factor difference (for example, by 10%) from the reference load factor on the basis of the load factor of the compressor 10 at the closing time of the bypass valve 51 or the opening degree adjustment time, the relative Thus, it is determined that the cooling performance of the water-cooled oil cooler 30 has been restored, and control may be performed to open the bypass valve 51 again.

[control information]

The storage unit 290 includes a first target tapping temperature Twt1, a second target tapping temperature Twt2, a first target oil temperature Tot1, a second target oil temperature Tot2, an upper limit water flow rate Qw1, and a lower limit. In addition to set values such as water flow rate (Qw2), various operation information required for control is stored.

Next, an example of the flow of control by the control unit 200 of the present embodiment will be described. 3 is a flowchart of water flow switching control and bypass valve control. 4A is a flowchart of constant control of the tapping temperature, and FIG. 4B is a flowchart of constant control of the discharge temperature.

First, the water flow switching control and the bypass valve control of FIG. 3 will be described in detail.

In step S11, the control unit 200 determines whether there is a hot water supply request based on the water level information of the hot water storage tank or the like.

When it is determined that there is a hot water supply request (step S11: YES), the water passing switching control unit 210 switches the water passing switching means to the water passing execution state. That is, in step S12 , the water flow switching control unit 210 opens the flow rate regulating valve 74 and drives the water supply pump 71 .

When it is determined that there is no hot water supply request (step S11: NO), the water flow switching control unit 210 switches the water flow switching means to the water flow stop state. That is, in step S13 , the water flow switching control unit 210 stops the water supply pump 71 and closes the flow rate control valve 74 .

In step S14, the control part 200 determines whether the forced closing flag of the bypass valve 51 is 1 or not.

When the forced closing flag is determined to be 1 (step S14: YES), since the condition for forcibly closing the bypass valve 51 is satisfied, the bypass valve control unit 220 controls the bypass valve 51 in step S17. close the

When it is determined that the forced closing flag is not 1, that is, 0 (step S14: NO), since the condition for forcibly closing the bypass valve 51 is not satisfied (or since the release condition has been established after the forced closing once) It shifts to the process of step S15.

In step S15, the control unit 200 determines whether or not the water is in the water passing execution state. When the flow rate regulating valve 74 is opened and the water supply pump 71 is driven in step S12, it becomes determination of the water passing execution state. On the other hand, when the water supply pump 71 is stopped and the flow rate regulating valve 74 is closed in step S13, it becomes determination of the water flow stop state.

When it is determined that the water supply is in the water passing state (step S15: YES), the bypass valve control unit 220 opens the bypass valve 51 in step S16. That is, the flow of the lubricating oil O1 is manipulated so that heat recovery in the water-cooled oil cooler 30 is promoted while suppressing heat radiation from the air-cooled oil cooler 40 .

When it is determined that the water flow is stopped (step S15: NO), the bypass valve control unit 220 closes the bypass valve 51 in step S17. That is, since the heat is not recovered by the water-cooled oil cooler 30 , the flow of the lubricant O1 is manipulated to promote heat dissipation from the air-cooled oil cooler 40 .

After the bypass valve 51 is opened, the lubricating oil temperature acquisition unit 270 acquires the lubricating oil temperature To detected by the lubricating oil temperature sensor 21 in step S18 .

The bypass valve control unit 220 determines whether the conditions for forcibly closing the bypass valve 51 (lubricating oil temperature To > first target oil temperature Tot1, and the elapse of a predetermined time) have been satisfied in step S19. judge

When it is determined that the condition for forced closing is satisfied (step S19: YES), the bypass valve control unit 220 sets 1 to the forced closing flag of the bypass valve 51 in step S20.

When it is determined that the condition for forced closing is not satisfied (step S19: NO), the process returns to the process of step S11.

After the bypass valve 51 is closed, the bypass valve control unit 220 controls the conditions for forcibly canceling the bypass valve 51 in step S21 (a decrease in the supply temperature of the cooling water W1 or the compressor 10 ). It is judged whether or not the load factor is reduced or not).

When it is determined that the conditions for releasing the forced closing of the bypass valve 51 are satisfied (step S21: YES), the bypass valve control unit 220 sets 0 to the forced closing flag of the bypass valve 51 in step S22. set up

When it is determined that the conditions for the forced closing release of the bypass valve 51 are not satisfied (step S21: NO), the process returns to the process of step S11.

Subsequently, the constant control of the tapping temperature of FIG. 4A will be described in detail.

In step S31, the control unit 200 determines whether or not the water passing execution state is present. Specific determination conditions are as described in step S15.

When it is determined in the water passing execution state (step S31: YES), the tapping temperature acquisition part 250 acquires the tapping temperature Tw detected by the tapping temperature sensor 75 in step S32.

When it is determined that the water flow is stopped (step S31: NO), the process of step S31 is repeated.

In step S33, the water flow control unit 230 uses the tapping temperature Tw as the feedback value (FB value), and the currently selected target tapping temperature Twt (the first target tapping temperature Twt1 or the second target tapping temperature). The operation amount of the flow control valve 74 or the feed water pump 71 is calculated using a predetermined algorithm while finding the deviation from the temperature Twt2).

In step S34, the water flow control part 230 performs opening degree adjustment of the flow rate control valve 74 or output adjustment (drive frequency adjustment) of the water supply pump 71 based on the calculated value of the manipulated variable. By repeating the process from step S32 to step S34, the water flow rate of the cooling water W1 is continuously adjusted, and the tapping temperature Tw converges to the target tapping temperature Twt.

During execution of the constant tapping temperature control, the target tapping temperature setting unit 240 monitors whether there is a request to change the target tapping temperature Twt (step S35). The change request of the target tapping temperature Twt is instructed by an external input through the operation panel or an internal processing based on a change in the physical amount of cooling water.

When it is determined that there is a change request (step S35: YES), the target tapping temperature setting unit 240 sets the first target tapping temperature Twt1 and the second target tapping temperature according to an external input or an instruction of an internal process in step S36. Select any one of (Twt2), and hold this as a set value.

When it is determined that there is no change request (step S35: NO), the target tapping temperature setting unit 240 maintains the currently selected setting value as it is.

Subsequently, the discharge temperature constant control of FIG. 4B will be described in detail.

In step S41, the control unit 200 determines whether or not the water passing execution state is present. Specific determination conditions are as described in step S15.

When it is determined in the water passing execution state (step S41: YES), the lubricating oil temperature acquisition part 270 acquires the lubricating oil temperature To detected by the lubricating oil temperature sensor 21 in step S42.

When it is determined that the water flow is stopped (step S41: NO), the process of step S41 is repeated.

In step S43, the water flow control unit 230 uses the lubricating oil temperature To as the feedback value (FB value), and the currently selected target oil temperature Tot (the first target oil temperature Tot1 or the second target oil). The operation amount of the flow control valve 74 or the feed water pump 71 is calculated using a predetermined algorithm while finding the deviation from the temperature Tot2).

In step S44, the water flow control part 230 performs opening degree adjustment of the flow control valve 74 or output adjustment (drive frequency adjustment) of the water supply pump 71 based on the calculated value of the manipulated variable. By repeating the process from step S42 to step S44, the water flow rate of the cooling water W1 is continuously adjusted, and the lubricating oil temperature To converges to the target oil temperature Tot.

During execution of the discharge temperature constant control, the target oil temperature setting unit 260 monitors whether there is a request to change the target oil temperature Tot (step S45). The change request of the target oil temperature Tot is instructed by an external input through the operation panel, or an internal process based on a change in the physical quantity of the lubricant.

When it is determined that there is a change request (step S45: YES), the target oil temperature setting unit 260 determines the first target oil temperature Tot1 and the second target oil temperature according to an external input or an internal processing instruction in step S46. Select any one of (Tot2) and hold it as a set value.

When it is determined that there is no change request (step S45: NO), the target oil temperature setting unit 260 maintains the currently selected setting value as it is.

5 : is a figure which shows typically the modified example of the air compression system 1 of 1st Embodiment.

In the present modification, a shutoff valve 52 is provided on the upstream side of the air-cooled oil cooler 40 to open and close the return oil line L30 downstream from the connection point of the first bypass line L31. In this modification, the shut-off valve 52 is provided in the communication pipe 63 .

In this case, the control unit 200 controls the shut-off valve 52 in addition to the water flow switching means and the bypass valve 51 . In more detail, the control unit 200 (bypass valve control unit 220 ) opens the bypass valve 51 and closes the shutoff valve 52 when the water flow switching means is in the water flow execution state, and switches the water flow When the means is in the water flow stop state, the bypass valve 51 is closed and the shutoff valve 52 is opened.

In this way, when the cooling water W1 is flowed into the water-cooled oil cooler 30 to recover heat, the bypass valve 51 is opened and the shut-off valve 52 is closed. The amount of heat recovery can be increased. In addition, the cooling amount in the air-cooled oil cooler 40 can be made zero. Thereby, in preventing excessive cooling of the lubricating oil O1 refluxing to the compressor body 11, by allowing the member cost of the shut-off valve 52 in addition to the member cost of the bypass valve 51 to facilitate the purpose can be achieved In addition, it is possible to prevent a situation in which the lubricating oil O1 after heat recovery in the water-cooled oil cooler 30 is cooled more than necessary in the air-cooled oil cooler 40 and sludge is precipitated in the lubricating oil O1.

In addition, in the case of this modification, in step S16 in the flowchart shown in FIG. 3, while opening the bypass valve 51, the shut-off valve 52 is closed. In addition, in step S17, while closing the bypass valve 51, the shut-off valve 52 is opened.

In addition, in this modification, the bypass valve 51 and the shut-off valve 52 can also be comprised by a three-way valve. This three-way valve is mounted at the branch point of the T-pipe 62 to open and close a valve mechanism for opening and closing the first bypass line (L31), and a return oil line (L30) on the upstream side of the air-cooled oil cooler (40). Acts as a valve mechanism. By operating the three-way valve, the bypass valve control unit 220 switches the flow of the lubricant O1 to a circulation route via the first bypass line L31 or a circulation route via the air-cooled oil cooler 40 . .

According to the air compression system 1 of 1st Embodiment demonstrated above, the following effects are exhibited.

(1) The air compression system 1 of the present embodiment includes an oil-cooled compressor main body 11, a first air supply line L10 through which compressed air A0 discharged from the compressor main body 11 flows, and a second 1 The oil separator 20 connected to the air supply line L10 and separating oil from the compressed air A0, and the second connected to the gas phase part of the oil separator 20 and through which the compressed air A1 after gas-liquid separation flows A gas supply line L20, a return oil line L30 connected to the liquid phase of the oil separator 20 and conveying the lubricating oil O1 after gas-liquid separation to the intake side of the compressor body 11, and a return oil line L30 ) installed in a water-cooled oil cooler 30 for heat recovery, a coolant line L50 that distributes the coolant W1 to the water-cooled oil cooler 30, and a water-cooled oil cooler 30 installed in the coolant line L50 A water supply pump 71 and a flow rate control valve 74 as water flow switching means for switching between the water flow execution state and the water flow stop state, and for heat dissipation installed in the return oil line L30 on the downstream side of the water cooling oil cooler 30 of the air-cooled oil cooler 40, a first bypass line L31 connected to the return oil line L30 and bypassing the lubricating oil O1 with respect to the air-cooled oil cooler 40, a first bypass line ( A bypass valve 51 that opens and closes L31, and a second bypass line connected to the return oil line L30 and bypassing the lubricating oil O1 with respect to the water-cooled oil cooler 30 and the air-cooled oil cooler 40 (L32) and a temperature control valve for adjusting the flow rate ratio of oil supply to the water-cooled oil cooler 30 and oil supply to the second bypass line L32 according to the temperature of the lubricating oil O1 after gas-liquid separation in the oil separator 20 53 and a control unit 200 for controlling the water flow switching means and the bypass valve 51, wherein the control unit 200 opens the bypass valve 51 when the water flow switching means is in the water flow execution state, , the bypass valve 51 is closed when the water flow switching means is in the water flow stop state.

Thereby, it is possible to prevent excessive cooling of the lubricating oil O1 flowing back to the compressor body 11 . More specifically, when the cooling water W1 is flowed into the water-cooled oil cooler 30 to recover heat, the bypass valve 51 is configured to open, so most (for example, 90% or more) or all of the lubricating oil ( O1) flows through the first bypass line L31 and the amount of oil supplied to the air-cooled oil cooler 40 is slightly (for example, less than 10%) or zero. Therefore, since the influence of cooling in the air-cooled oil cooler 40 is minimized, the lubricating oil O1 returned to the compressor body 11 is not excessively cooled and the lubricating oil O1 returned to the compressor body 11 is cooled to an appropriate temperature range. maintain. Thereby, the required heat recovery amount can be ensured without reducing the oil supply amount to the water-cooled oil cooler 30 .

Also, this configuration is particularly in the case of an aspect in which other parts of the air compression system 1 are simultaneously cooled (eg, control box) or ventilated (eg, inside a housing) by means of a cooling fan 42 . Valid. In this case, it is common that the cooling fan 42 is controlled to the minimum rotation speed or more while the compressor body 11 is operating, but even in this case, most or all of the lubricant oil O1 passes through the first bypass line L31. It is possible to prevent excessive cooling of the lubricating oil O1 refluxing to the compressor body 11 by the flow.

In addition, when the bypass valve 51 is opened, the coolant W1 supplied to the water-cooled oil cooler 30 is low temperature or the lubricating oil O1 delivered from the oil separator 20 is When it cools too much, a part of lubricating oil O1 is bypassed with respect to the water-cooled oil cooler 30 by the temperature control valve 53. As shown in FIG. Thereby, the lubricating oil O1 conveyed to the compressor main body 11 can be maintained in the appropriate temperature range while heat recovery is actively performed by the water-cooled oil cooler 30. As shown in FIG.

(2) The bypass valve 51 of the air compression system 1 of this embodiment is provided in the first bypass line L31, and the return oil line L30 and the first bypass line L31 are upstream A straight pipe 61, an outlet pipe 30A of the water-cooled oil cooler 30 is connected to the starting end of the side, and an inlet port 51A of the bypass valve 51 is connected to a downstream end, and a straight pipe ( A communication pipe (62) for communicating the branching T-pipe 62 attached to the intermediate part of 61, the inlet pipe 40A of the air-cooled oil cooler 40, and the branch port 62A of the T-pipe 62 63) is included.

As a result, when the bypass valve 51 is opened, the first flow of lubricating oil O1 that has passed through the water-cooled oil cooler 30 is supplied to the bypass valve 51 through the straight pipe 61, so the bypass valve 51 is bypassed. In the process of passing through the pass valve 51, a relatively small friction loss is only received in the valve chamber. On the other hand, in the second classification, since oil is supplied to the air-cooled oil cooler 40 through the T-pipe 62 , it receives a branch loss in the T-pipe 62 , and in the process of passing the air-cooled oil cooler 40 , relatively large friction The losses are received in the air cooled oil cooler 40 . Therefore, the flow rate ratio of the lubricating oil O1 becomes "first flow > second flow", and most of the lubricating oil O1 flows through the bypass side. Thereby, in preventing excessive cooling of the lubricating oil O1 refluxing to the compressor body 11, the purpose can be achieved inexpensively only by adjusting the pipe resistance without installing a shut-off valve on the air-cooled oil cooler 40 side. can

(3) The air compression system 1 of this embodiment is an upstream side of the air-cooled oil cooler 40, and a shut-off valve which opens and closes the return oil line L30 downstream from the connection point of the 1st bypass line L31. 52 and a control unit 200 for controlling the water flow switching means, the bypass valve 51 and the shutoff valve 52, wherein the control unit 200 controls the bypass valve when the water flow switching means is in the water flow execution state. While opening (51), the shutoff valve (52) is closed, and when the water flow switching means is in the water flow stop state, the bypass valve (51) is closed and the shutoff valve (52) is opened.

In this way, when the cooling water W1 is flowed into the water-cooled oil cooler 30 to recover heat, the bypass valve 51 is opened and the shut-off valve 52 is closed. The amount of heat recovery can be increased. In addition, the cooling amount in the air-cooled oil cooler 40 can be made zero. Thereby, in preventing excessive cooling of the lubricating oil O1 refluxing to the compressor body 11, by allowing the member cost of the shut-off valve 52 in addition to the member cost of the bypass valve 51 to facilitate the purpose can be achieved In addition, it is possible to prevent a situation in which the lubricating oil O1 after heat recovery in the water-cooled oil cooler 30 is cooled more than necessary in the air-cooled oil cooler 40 and sludge is precipitated in the lubricating oil O1.

(4) The water-cooled oil cooler 30 of the air compression system 1 of the present embodiment is a plate heat exchanger in which heat transfer plates made of titanium are laminated.

As a result, even when the cooling water W1 supplied to the water-cooled oil cooler 30 contains oxidizing agents such as residual chlorine or corrosive ions such as chloride ions, high-temperature corrosion occurring on the heat transfer surface or junction of the water-cooled oil cooler 30 . can be suppressed.

(5) The air compression system 1 of the present embodiment includes a tap temperature sensor 75 that detects a tap temperature T1 of the cooling water W1 after passing through the water-cooled oil cooler 30, and the water flow switching means includes: In addition to the switching of the water passing state, the water passing flow rate is adjustable, and the control unit 200 switches the water passing switching means to the water passing execution state, and the tapping temperature T1 detected by the tapping temperature sensor 75 is the target tapping temperature. Adjust the water flow rate to (Twt).

Thereby, the hot water W2 can be supplied stably at the hot water supply temperature requested|required by a hot water demand place.

(6) In the air compression system 1 of the present embodiment, the target tapping temperature Twt is the first target tapping temperature Twt1 and a second target tapping temperature lower than the first target tapping temperature Twt1 ( Twt2), and the control unit 200 includes a target tapping temperature setting unit 240 capable of selecting any one of the first target tapping temperature Twt1 and the second target tapping temperature Twt2.

As a result, in the state where the first target tapping temperature Twt1 is selected, thermal stress generated at the heat transfer surface of the water-cooled oil cooler 30 or the member junction is relieved, and stable heat recovery can be realized without causing damage due to material deterioration. have.

In addition, when the hot water W2 is used for boiler feed water in a state where the second target tapping temperature Twt2 is selected, the fuel consumption of the steam boiler can be effectively reduced, thereby contributing to energy saving.

(7) In the air compression system 1 of this embodiment, the temperature of the lubricating oil O1 discharged together with the compressed air A1 from the compressor main body 11, or the lubricating oil O1 after gas-liquid separation in the oil separator 20 a lubricant temperature sensor 21 for detecting the temperature of the water passing switching means is configured to adjust the water flow rate in addition to switching of the water passing state, and the control unit 200 is switching the water passing switching means to the water passing execution state , Adjust the water flow rate so that the detection temperature To of the lubricating oil temperature sensor 21 becomes the target oil temperature Tot.

Thereby, the lubricating oil O1 can be circulated stably at an appropriate lubricating oil temperature To.

(8) In the air compression system 1 of this embodiment, the target oil temperature Tot is the first target oil temperature Tot1 and a second target oil temperature lower than the first target oil temperature Tot1 ( Tot2), and the control unit 200 includes a target oil temperature setting unit 260 that can select either one of the first target oil temperature Tot1 and the second target oil temperature Tot2.

As a result, in the state in which the first target oil temperature Tot1 is selected, the lubricant can be used without deterioration until the recommended replacement time of the lubricant manufacturer arrives. As a result, it is possible to avoid a failure due to poor cooling and lubrication of the compressor main body 11 .

In addition, in the state in which the second target oil temperature Tot2 is selected, condensed water does not mix with the lubricating oil to cause a change in properties, so that failure due to poor cooling and lubrication of the compressor body 11 can be avoided. In addition, since various oxidizing gases (oxygen gas and carbon dioxide in the air, NOx and SOx flowing into the air from exhaust gas in a factory, etc.) are not dissolved in the condensate, unexpected corrosion of compression mechanisms (screw rotors and bearings, etc.) is avoided. You may.

(9) The control unit 200 of the air compression system 1 of the present embodiment adjusts the water passage flow rate by the water passage switching means within the range of the upper limit water passage flow rate Qw1 and the lower limit water passage flow rate Qw2.

By setting such an upper limit water flow rate Qw1, hot water is not supplied at an excessive flow rate that lacks a balance with respect to the demand for hot water. Therefore, it is possible to prevent performance degradation or failure due to overload of water supply equipment (inverter drive pumps, water control pumps, etc.). In addition, since the upper limit water flow rate Qw1 is set in consideration of a state in which the hot water demand amount of the hot water-using device is increased, an unexpected stop of the hot water-using device due to the insufficient amount of hot water is avoided.

In addition, by setting the lower limit water flow rate Qw2, the impurity removal/separation capability of the water treatment device 72, that is, the water quality after treatment is guaranteed. Therefore, it is possible to extend the lifespan of not only hot water equipment but also hot water supply pipes in facilities.

(10) When the control unit 200 of the air compression system 1 of the present embodiment elapses in a state where the detection temperature To of the lubricant temperature sensor 21 exceeds the first target oil temperature Tot1, a predetermined time has elapsed. In this case, the bypass valve 51 is also adjusted to close or open.

As a result, even if the water flow rate of the cooling water W1 is increased to the maximum within the allowable range, when the lubricating oil O1 cannot be sufficiently cooled by the water cooling oil cooler 30 main body, the bypass valve 51 is closed to water cooling. The cooling of the two-step method of the oil cooler 30 and the air-cooled oil cooler 40 is performed. Thereby, the lubricating oil O1 can be reliably lowered to less than the upper limit oil temperature (for example, 80 degreeC).

Next, a second embodiment will be described. 6 : is a figure which shows typically the structure of the air compression system 1 which concerns on 2nd Embodiment. In addition, in 2nd Embodiment, about the structure similar to 1st Embodiment, the same code|symbol is attached|subjected and the description may be abbreviate|omitted. In the air compression system 1 of this embodiment, heat is also recovered from the compressed air A1 after gas-liquid separation by the oil separator 20 .

As shown in FIG. 6, in the air compression system 1 of this embodiment, the water-cooled air cooler 80 for heat recovery is provided in the 2nd air supply line L20. Further, on the downstream side of the water-cooled air cooler 80, an air-cooled air cooler 90 for heat dissipation is provided. The compressed air A1 passing through the water-cooled air cooler 80 flows into the air-cooled air cooler 90 and is further cooled.

The water-cooled air cooler 80 is a heat exchanger for recovering the compressed heat of the compressed air A1 after gas-liquid separation flowing through the second air supply line L20. A cooling water line L50 through which the cooling water W1 flows is connected to the water cooling air cooler 80 . Here, the water-cooled air cooler 80, together with the water-cooled oil cooler 30, performs heat exchange between the cooling water W1 and the high-temperature fluid, and is provided as a heat exchanger for producing hot water W2 from the cooling water W1.

Here, the cooling water line L50 has a connection configuration in which the cooling water W1 flows in parallel to the water-cooled oil cooler 30 and the water-cooled air cooler 80 .

And the water supply pump 71 and the flow control valve 74 as water flow switching means are means for switching the water-cooled oil cooler 30 and the water-cooled air cooler 80 to the same water flow state.

As this water-cooled air cooler 80, for example, a plate-type heat exchanger in which heat transfer plates made of titanium are laminated are used. However, since the temperature of compressed air A1 after gas-liquid separation is sufficiently lower than that of lubricating oil, for example, a plate heat exchanger in which heat transfer plates made of stainless steel are laminated may be used.

The air-cooled air cooler 90 includes a heat exchanger 91 (a heat exchange core made of an aggregate such as plate fins and fin tubes), a cooling fan 92 , and a fan motor 93 for rotating the cooling fan 92 . to provide By rotating the cooling fan 92, heat exchange is performed between the air blown by the cooling fan 92 and the compressed air A1 flowing through the heat exchanger 91, and the compressed air A1 is cooled.

In addition, the cooling fan 92 of the air-cooled air cooler 90 and the cooling fan 42 of the air-cooled oil cooler 40 are common, and the heat exchanger 91 of the air-cooled air cooler 90 and A configuration in which the heat exchanger 41 of the air-cooled oil cooler 40 is cooled may be employed.

With the above configuration, heat is recovered from both the lubricating oil O1 and the compressed air A1 to produce the hot water W2, so that the heat recovery rate can be increased and further energy saving can be achieved.

In addition, moisture is removed from the compressed air (A1) flowing through the heat-recovered second air supply line (L20) using a dryer (not shown), and the compressed air (A1) dried after the moisture has been removed is transferred to a compressed air using device ( (not shown) may also be sent.

7 : is a figure which shows typically the modified example of the air compression system 1 of 2nd Embodiment.

In this modified example, the cooling water line L50 has a connection structure in which the cooling water W1 flows in series to the water-cooled oil cooler 30 and the water-cooled air cooler 80 . Also in such a structure, the effect similar to the above-mentioned effect can be acquired.

In addition, when the cooling water W1 is flowed in series, heat is first recovered by the water-cooled air cooler 80 with respect to the compressed air A1 having a small amount of heat, and then the lubricating oil O1 having a larger amount of heat than the compressed air A1. With respect to the heat recovery in the water-cooled oil cooler (30). Thereby, heat recovery|recovery can be performed more effectively.

According to the air compression system 1 of 2nd Embodiment demonstrated above, in addition to (1)-(10), the following effects are exhibited.

(11) In the air compression system 1 of this embodiment, the water-cooled air cooler 80 for heat recovery provided in the 2nd air supply line L20, and the air-cooling for heat radiation provided downstream of the water-cooled air cooler 80. The air cooler 90 is provided, and the cooling water line L50 is a connection configuration that distributes the cooling water W1 in series or parallel to the water-cooled oil cooler 30 and the water-cooled air cooler 80 , and the water flow switching means is water cooling. It is a means for switching the oil cooler 30 and the water-cooled air cooler 80 to the same water flow state.

Thereby, since heat is recovered from both the lubricant oil O1 and the compressed air A1 to produce the hot water W2, the heat recovery rate can be increased and further energy saving can be achieved.

As mentioned above, although preferred embodiment of the water supply system of this invention was described, this invention is not restrict|limited to the above-mentioned embodiment, A change is possible as appropriate.

1 air compression system 10 compressor
11 Compressor body 20 Oil separator
21 Lubricating oil temperature sensor 30 Water cooling oil cooler
30A outlet pipe 40 air cooled oil cooler
40A inlet tube 51 bypass valve
51A Inlet Port 52 Shutoff Valve
53 Temperature control valve 60 Bypass branch
61 straight tube 62 T-shaped tube
62A branch port 63 through pipe
71 Water pump (flow switching means) 72 Water treatment unit
73 flow sensor
74 Flow control valve (flow switching means)
75 Hot water temperature sensor 80 Water cooling air cooler
90 Air cooling air cooler 200 Control unit (control means)
L10 1st air supply line L20 2nd air supply line
L30 return oil line L31 1st bypass line
L32 2nd Bypass Line L50 Coolant Line
A0 Compressed air before gas-liquid separation A1 Compressed air after gas-liquid separation
O1 lubricant W1 coolant
W2 hot water

Claims (11)

an oil-cooled compressor body;
a first air supply line through which the compressed air discharged from the compressor body flows;
an oil separator connected to the first air supply line and separating oil from compressed air;
a second air supply line connected to the gas phase part of the oil separator through which compressed air after gas-liquid separation flows;
a return oil line connected to the liquid phase of the oil separator and conveying the lubricating oil after gas-liquid separation to the intake side of the compressor body;
a water-cooled oil cooler for heat recovery installed in the return oil line;
a cooling water line for distributing cooling water to the water cooling oil cooler;
a water flow switching means installed in the cooling water line and configured to switch a water flow execution state and a water flow stop state for the water-cooled oil cooler;
an air-cooled oil cooler for heat dissipation installed in the return oil line downstream of the water-cooled oil cooler;
a first bypass line connected to the return oil line and bypassing the lubricating oil with respect to the air-cooled oil cooler;
a bypass valve for opening and closing the first bypass line;
a second bypass line connected to the return oil line and bypassing the lubricating oil with respect to the water-cooled oil cooler and the air-cooled oil cooler;
a temperature control valve for adjusting a flow rate ratio of oil supply to the water-cooled oil cooler and oil supply to the second bypass line according to the temperature of the lubricating oil after gas-liquid separation in the oil separator;
a control means for controlling the water flow switching means and the bypass valve;
and the control means opens the bypass valve when the water flow switching means is in a water flow execution state, and closes the bypass valve when the water flow switching means is in a water flow stop status. The method of claim 1,
The bypass valve is installed in the first bypass line,
The return oil line and the first bypass line are
a straight pipe having an outlet pipe of the water-cooled oil cooler connected to an upstream end and an inlet port of the bypass valve connected to a downstream end;
A T-pipe for branching mounted on the middle part of the straight pipe,
An air compression system comprising a communication pipe communicating the inlet pipe of the air-cooled oil cooler and the branch port of the T-tube. The method of claim 1,
a shut-off valve that is upstream of the air-cooled oil cooler and opens and closes the return oil line downstream of the connection point of the first bypass line;
a control means for controlling the water flow switching means, the bypass valve and the shut-off valve;
the control means opens the bypass valve and closes the shut-off valve when the water flow switching means is in the water flow execution state, and closes the bypass valve when the water flow switching means is in the water flow stop status; In addition, an air compression system for opening the shutoff valve. 4. The method according to any one of claims 1 to 3,
The water-cooled oil cooler is an air compression system that is a plate-type heat exchanger in which heat transfer plates made of titanium are laminated. 4. The method according to any one of claims 1 to 3,
a water-cooled air cooler for heat recovery installed in the second air supply line;
and an air-cooled air cooler for heat dissipation installed on a downstream side of the water-cooled air cooler,
The cooling water line is a connection configuration that distributes cooling water in series or in parallel to the water-cooled oil cooler and the water-cooled air cooler,
The water flow switching means is a means for switching the water-cooled oil cooler and the water-cooled air cooler to the same water flow state. The method of claim 1,
and a tapping temperature sensor for detecting the tapping temperature of the coolant after passing through the water-cooled oil cooler,
The water passing switching means is configured to adjust the water flow rate in addition to the water passing state switching,
The control means adjusts the flow rate of water passing so that the tap temperature detected by the tap temperature sensor becomes a target tap temperature while the water passing switching means is switched to the water passing execution state. 7. The method of claim 6,
The target tapping temperature includes a first target tapping temperature and a second target tapping temperature lower than the first target tapping temperature;
and the control means includes a target tapping temperature setting means capable of selecting any one of the first target tapping temperature and the second target tapping temperature. The method of claim 1,
a lubricating oil temperature sensor for detecting the temperature of the lubricating oil discharged together with the compressed air from the compressor body or the temperature of the lubricating oil after gas-liquid separation in the oil separator;
The water passing switching means is configured to adjust the water flow rate in addition to the water passing state switching,
The control means adjusts the water flow rate so that the temperature detected by the lubricant temperature sensor becomes a target oil temperature while the water flow switching means is switched to the water passing execution state. 9. The method of claim 8,
the target oil temperature includes a first target oil temperature and a second target oil temperature lower than the first target oil temperature;
and the control means includes target oil temperature setting means capable of selecting either one of the first target oil temperature and the second target oil temperature. 10. The method according to any one of claims 6 to 9,
The control means adjusts the water flow rate by the water flow switching means within the range of an upper limit water flow rate and a lower limit water flow rate. 10. The method of claim 9,
The control means closes or adjusts the degree of opening of the bypass valve when a predetermined time has elapsed in a state where the detection temperature of the lubricant temperature sensor exceeds the first target oil temperature.

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