JP4771825B2 - Circulating water exchanging method and circulating water exchanging apparatus in water circulation type compressor - Google Patents

Description

  The present invention relates to a circulating water exchanging method and a circulating water exchanging apparatus for a water circulating compressor, and more particularly, to maintain the quality of circulating water in a water circulating compressor that uses water from which impurities have been removed by a deionizer as circulating water. It is related with the circulating water exchange method and apparatus for performing.

  It is generally used for cooling, sealing, and lubrication to obtain compressed air that is used in fields such as food manufacturing machines that cannot use compressed air containing oil, or that cannot use compressed air containing oil. There is a water circulation type compressor that compresses intake air by sucking water together with air instead of oil.

  In this water circulation compressor, the water supplied into the compressor body together with the air is discharged together with the compressed air, introduced into the separator receiver tank, and separated into compressed air and water in the separator receiver tank. The circulating water separated from the compressed air in the separator receiver tank is supplied again to the compressor body through a radiator, a filter, etc., and used for cooling, sealing, etc. during the compression work.

  As described above, in the water circulation type compressor, a circulating water circulation system formed by the compressor body, the separator receiver tank, the radiator and the pipes connecting these is formed. Is configured such that a water supply circuit connected to an external water supply source is connected, and water can be supplied into the circulation system of the circulating water by opening and closing an on-off valve provided in the water supply circuit.

  By the way, as an external water supply source used for such water supply, tap water (water supply) is generally used, but water introduced from such an external water supply source contains impurities such as metal ions. . For this reason, when water containing such impurities is introduced into the circulation system of the circulating water, the metal ions in the circulating water are concentrated when the circulating water evaporates and decreases due to heat during compression work. The concentrated metal ions crystallize and precipitate, causing problems such as clogging of piping.

  Therefore, in order to correct such harmful effects caused by the deposition of metal ions, a water circulation compressor is provided with a deionizer, and impurities contained in the water supplied from the external water supply source are removed in advance by this deionizer. After approaching water, it is introduced into the circulatory system.

  However, even if the pure water that has passed through the deionizer is introduced as circulating water in this way, the metal material used in the compressor piping, etc., becomes ions and dissolves in the circulating water. Impurities such as metal ions in the water increase and the quality of the circulating water deteriorates.

  Therefore, a method has been proposed in which the quality of the circulating water is improved by replacing the circulating water every time the cumulative operation time of the compressor reaches a predetermined time.

  Another method is to provide a bypass circuit in the circulating water circulation system, introduce the circulating water in the circulation system into the deionizer, remove impurities, and then return to the circulation system again. It has been proposed to maintain the water quality (see Patent Document 1).

Prior art document information of the present invention includes the following.
Japanese Patent No. 30653302

  In the water circulation type compressor, the deterioration of the quality of the circulating water is not only caused by the elution of the metal material used in the piping and the like into the circulating water as described above, but also by the outside air to be sucked.

  That is, if impurities are contained in the inhaled outside air, these impurities dissolve in the circulating water during compression and the like, and by repeating this operation, the impurities are gradually accumulated in the circulating water and the water quality deteriorates.

  Such deterioration of the water quality is affected by the state of the outside air sucked by the compressor, and when the outside air sucked contains a large amount of impurities, the quality of the circulating water is lowered in a relatively short time, while being sucked. If there are few impurities in the outside air, the quality of the circulating water will not decrease for a relatively long time.

  As described above, the progress of the deterioration of the quality of the circulating water changes depending on factors other than the cumulative operation time of the compressor, but the method of the prior art in which the circulating water is uniformly replaced by the cumulative operation time of the compressor. For example, even if the quality of the circulating water has already deteriorated to the extent that it needs to be replaced, it will be used without being replaced when the cumulative operating time of the compressor is less than the set time. This may cause problems such as clogging.

  Conversely, if the circulating water is replaced over the set cumulative operating time even though the quality of the circulating water has not deteriorated, the circulating water will be excessively replaced, and the external water supply source The frequency of use of the deionizer for treating the water supplied from the plant increases, and the frequency of replacement of the relatively expensive deionizer or the ion exchange resin cartridge of the deionizer increases, which is not economical.

  On the other hand, in the prior art cited as the above-mentioned Patent Document 1, the quality of the circulating water can be maintained by bypassing a part of the circulating water to the deionizer. There is a problem that it becomes complicated.

  Therefore, the present invention has been made to eliminate the above-mentioned drawbacks of the prior art. When the water quality of the circulating water has deteriorated to such an extent that it needs to be replaced by a relatively simple configuration, only the necessary amount is required at any time. By providing a circulating water replacement method and device that can be replaced, it is possible to suitably prevent occurrence of clogging of piping due to insufficient replacement of circulating water, and to make it possible to replace circulating water economically. For the purpose.

In order to achieve the above object, a circulating water exchange method in a water circulation type compressor of the present invention communicates with a compressor body 10 for compressing intake air together with circulating water, and a discharge port 11 of the compressor body 10. A separator receiver tank 20 for introducing compressed air and circulating water discharged from the main body 10 to separate and store the compressed air and circulating water is provided, and the circulating water is provided between the compressor main body 10 and the separator receiver tank 20. In the water circulation type compressor 1 in which the circulation system is formed,
When the electrical conductivity Sm of the circulating water in the circulation system becomes equal to or higher than the first reference value Ss1 set in advance, the supply water from the external water supply source that has passed through the deionizer 45 is introduced into the circulation system. Alternately performing water supply and drainage for discharging part of the circulating water in the circulation system,
The water supply / drainage is repeated until the electrical conductivity of the circulating water becomes less than a second reference value Ss2 set to a predetermined low value with respect to the first reference value Ss1 (Claim 1).

  In the above circulating water exchange method, the water supply / drainage to the circulation system is preferably performed according to the following steps.

When the electrical conductivity Sm of the circulating water becomes equal to or higher than the first reference value Ss1, a first stage of starting water supply to the circulating system;
A second stage in which when the water level in the separator receiver tank 20 reaches a predetermined upper limit position Lh, the water supply started in the first stage is stopped and the drainage of the circulating water is started;
When the water level in the separator receiver tank 20 reaches a predetermined lower limit position L1, the third stage of stopping the drainage started in the second stage and restarting the water supply to the circulation system;
When the electrical conductivity Sm of the circulating water when the water level in the separator receiver tank 20 reaches the predetermined intermediate position Lm is less than the second reference value Ss2, the water supply started in the three steps is stopped. The step of ending the water supply / drainage treatment or the step of continuing the water supply started in the third step and repeating the processing after the second step when the second reference value Ss2 or more is reached (Claim 2).

  In the circulating water exchanging method described above, the electrical conductivity Sm of the circulating water is obtained by measuring this a predetermined number of times every predetermined time and obtaining an average value of the electrical conductivity measured the predetermined number of times. An average value of electrical conductivity may be compared with the first and second reference values.

Further, the circulating water exchange device in the water circulation compressor of the present invention includes a water circulation compressor 1 having the same basic configuration as described above.
A water supply circuit 50 that includes a pure water device 45 and communicates an external water supply source with the circulation system;
A drain circuit 33 communicated with the circulation system;
An electrical conductivity measuring means 61 such as an electrical conductivity meter or a resistance meter for measuring the electrical conductivity of the circulating water in the circulation system;
Opening and closing means (electromagnetic on-off valves SV1 and SV2 in the illustrated example) for the water supply circuit 50 and the drain circuit 33 are provided, respectively.
The electrical conductivity Sm measured by the electrical conductivity measuring means 61 is set to a first reference value Ss1, which is set in advance, and a second reference value Ss2, which is set lower than the first reference value Ss1, by a predetermined value. In comparison, when the measured electrical conductivity Sm is equal to or higher than the first reference value Ss1, the opening and closing means SV1 and SV2 provided in the water supply circuit 50 and the drain circuit 33 are controlled to open and close to the water supply to the circulation system. And a control means 70 for alternately supplying and discharging the circulating water until the electrical conductivity Sm of the circulating water becomes less than the second reference value Ss2. It is characterized (claim 4).

  In the circulating water exchanging apparatus having the above-described configuration, a water level detecting means (a level switch 62 in the illustrated example) for detecting the water level in the separator receiver tank 20 is further provided, and the control means 70 is configured according to the following steps. It can be configured to perform opening / closing control of the opening / closing means SV1, SV2.

The electric conductivity Sm measured by the electric conductivity measuring means 61 is compared with the first reference value Ss1, and when the measured electric conductivity Sm is greater than or equal to the first reference value Ss1, the water supply circuit 50 A first stage of opening the opening / closing means SV1 of
When the water level detecting means 62 detects a water level at a predetermined upper limit position Lh, a second stage of closing the opening / closing means SV1 of the water supply circuit 50 and opening the opening / closing means SV2 of the drain circuit 33;
A third stage of closing the opening / closing means SV2 of the drain circuit 33 and opening the opening / closing means SV1 of the water supply circuit 50 when the water level detecting means 62 detects a water level at a predetermined lower limit position Ll;
When the water level detecting means 62 detects the water level at the predetermined intermediate position Lm, the electric conductivity Sm measured by the electric conductivity measuring means 61 is measured by comparing with the second reference value Ss2. When the electrical conductivity Sm is less than the second reference value Ss2, the step of closing the water supply / drainage by closing the opening / closing means SV1 of the water supply circuit 50, or when the electric conductivity Sm is equal to or greater than the second reference value Ss2, A step of repeating the control after the second step while maintaining the open / close means SV1 in an open state (Claim 5).

  The control unit 70 acquires the electrical conductivity measured by the electrical conductivity measuring unit 61 a predetermined number of times at predetermined time intervals, and calculates the average value of the acquired predetermined times of electrical conductivity. At the same time, the average value may be compared with the first and second electrical conductivities.

  With the configuration of the present invention described above, according to the circulating water exchanging method and the circulating water exchanging apparatus of the present invention, the circulating water is based on the measured electrical conductivity Sm of the circulating water regardless of the cumulative operation time of the compressor 1. When the water quality has deteriorated to the extent that it needs to be replaced, it is possible to replace the circulating water at any time and to replace only the required amount of circulating water, preventing insufficient or excessive replacement of the circulating water. We were able to.

  As a result, it is possible to suitably prevent the precipitation of impurities such as metal ions due to insufficient replacement of circulating water and the clogging of piping based on this, and the ion exchange resin of the deionizer 45 due to excessive replacement of circulating water. It has become possible to exchange the circulating water economically, preventing a decline in capacity.

  In addition, since the water supply and drainage for the circulation system are repeated and the circulation water is replaced part by part, the circulation water can be exchanged during the operation of the water circulation compressor 1, and the work is stopped when the circulation water is exchanged. There is no need to do.

  Furthermore, by exchanging the circulating water in accordance with the water level in the separator receiver tank 20, the circulating water in the circulation system can be maintained at a suitable amount.

  The electrical conductivity Sm of the circulating water is measured a predetermined number of times every predetermined time, and the electrical conductivity of the circulating water is compared with a reference value based on the average value of the electrical conductivity measured the predetermined number of times. In this case, the accuracy of the measured value of electrical conductivity could be ensured, and the operation due to temporary fluctuation could be suitably prevented.

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

[Basic configuration of water circulation compressor]
In FIG. 1, reference numeral 1 denotes a water circulation compressor. The water circulation compressor includes a compressor body 10 that compresses compressed air together with the circulating water, and a discharge circuit 31 is connected to a discharge port 11 of the compressor body 10. And a separator receiver tank 20 for introducing compressed air discharged from the compressor body 10 as a gas-liquid mixed fluid with circulating water.

  The separator receiver tank 20 is provided with a return circuit 32 for introducing the circulating water separated from the compressed air in the separator receiver tank 20 into the water supply port 12 of the compressor body 10. The separator receiver tank 20 and the discharge circuit 31 and the return circuit 32 that communicate with each other form a system (circulation system) through which the circulating water circulates.

  In FIG. 1, reference numeral 41 shown in the return circuit 32 is a radiator, and reference numeral 42 is a water filter, which cools and circulates the circulating water in the separator receiver tank 20 and supplies the water supply port of the compressor body 10. 12 is introduced.

[Circulating water exchanger]
In the water circulation compressor 1 having the basic configuration as described above, the circulating water exchange device of the present invention has a configuration for supplying water to the circulation system (water supply unit) and a configuration for discharging water from the circulation system (drainage). Part) and the structure (control part) for controlling the water supply and drainage are provided with the following structures.

1. Water supply unit In order to supply water to the circulation system of the circulating water, a water supply circuit 50 is provided for introducing supply water from an external water supply source into the circulation system.

  The connection position of the water supply circuit 50 can be appropriately changed as long as the supply water from the external supply source can be introduced into the circulation system of the circulating water, but in the present embodiment, the water supply circuit 50 One end of 50 is communicated with an external water supply source such as a water supply via an on-off valve 43, and the other end is communicated with the intake side of the compressor body 10 to enable water supply during operation of the compressor 1.

  Then, a water filter 44 and a deionizer 45 are arranged in this water supply circuit 50 in order from the upstream side, and the water supplied from the external water source is filtered by the water filter 44 and then formed into deionized water by the deionizer 45. The pure water from which impurities are removed can be supplied into the circulating system.

  The water supply circuit 50 is provided with an electromagnetic on-off valve (normally closed type in the present embodiment) SV1, which is an opening / closing means of the water supply circuit 50. The electromagnetic on-off valve SV1 is provided from a control means 70 described later. The water supply circuit 50 is opened and closed by controlling with the electrical signal of the above, and the water supply to the circulation system can be started and stopped.

2. Drainage unit In order to drain the circulating water in the circulation system to the outside of the machine, a drainage circuit 33 that connects one end to the circulation system is provided.

  In the illustrated embodiment, one end of the drain circuit 33 is connected to the separator receiver tank 20, and the circulating water stored in the separator receiver tank 20 can be drained by the pressure in the separator receiver tank 20. .

  However, the drain circuit 33 may communicate with any position in the circulation system as long as it allows drainage of the circulating water. For example, the drain circuit 33 communicates with the return circuit 32 at other positions in the circulation system. It is good also as what communicates.

  As shown in FIG. 1, this drain circuit 33 is provided with an electromagnetic on-off valve (normally closed type in this embodiment) SV2 as an opening / closing means for opening and closing the drain circuit 33, and this electromagnetic on-off valve SV2 will be described later. The drainage of the circulating water in the circulation system can be started and stopped by controlling with an electric signal from the control means 70.

3. Control unit In order to perform opening / closing control of the opening / closing means (electromagnetic opening / closing valve SV1) of the water supply circuit 50 and the opening / closing means (electromagnetic opening / closing valve SV2) of the drain circuit 33 to supply and drain the circulation system in a predetermined procedure, The circulating water exchange device of the present invention detects the water level in the separator receiver tank 20 and the electrical conductivity measuring means 61 for measuring the electrical conductivity (or the resistivity which is the reciprocal) of the circulating water in the circulation system. Control means 70 for controlling the opening / closing of the solenoid valves SV1 and SV2 in accordance with a predetermined stage based on the measurement result of the water level detection means 62 and the electrical conductivity measurement means 61 and the detection signal of the water level detection means 62. Is provided.

(1) Electrical conductivity measurement means The electrical conductivity measurement means 61 measures the electrical conductivity Sm of the circulating water in the circulation system, and outputs the measurement result to the control means 70 described later as an electrical signal.

  As the electrical conductivity measuring means 61, various known electrical conductivity meters can be used, and since the electrical conductivity is the reciprocal of the resistivity, the resistance meter is used instead of the electrical conductivity meter. It is good also as what measures electrical conductivity (resistivity) of feed water by this.

  In the illustrated embodiment, the electrical conductivity measuring means 61 is provided in a return circuit 32 for introducing the circulating water separated by the separator receiver tank 20 into the water supply port 12 of the compressor body 10. However, the electrical conductivity measuring means 61 may be provided at any position in the circulation system as long as the electrical conductivity Sm of the circulating water can be measured. For example, the circulating water in the separator receiver tank 20 may be provided. You may make it measure the electrical conductivity of.

(2) Water level detection means The water level detection means 62 detects the water level in the separator receiver tank 20 and outputs the detected water level to the control means 70 described later. The control means 70 described later performs electrical conduction by the electric conductivity measuring means 61 described above. Along with the rate, the electromagnetic on-off valves SV1, SV2 are controlled to open / close based on the detection signal.

  In this embodiment, a level switch 62 is disposed in the separator receiver tank 20 as the water level measuring means, and the level switch 62 sets the water level in the separator receiver tank 20 to the upper limit position Lh, the intermediate position Lm, and the lower limit. Detection is possible at three positions Ll.

  In the present embodiment, the switches of the upper limit position Lh, the intermediate position Lm, and the lower limit position Ll provided on the level switch 62 are arranged at equal intervals, and between the upper limit position Lh and the intermediate position Lm and between Between the position Lm and the lower limit position Ll, the same amount of circulating water can be stored. Therefore, not only the water level but also the water amount can be measured by the level switch 62.

(3) Control means The control means 70 receives the electrical signals from the electrical conductivity measurement means 61 and the water level detection means (level switch 62) described above, and electromagnetically opens and closes the water supply circuit 50 according to the received electrical signals. The valve SV1, and the electromagnetic on-off valve SV2 provided in the drain circuit 33 are controlled to open and close in accordance with a preset program or the like, and are realized by an electronic control unit or the like that stores the program.

  The control by the control means 70 will be described below with reference to FIGS.

  As will be described later, the replacement of the circulating water by the apparatus of the present invention is performed by replacing the circulating water partly with the supply water, and the supplied pure water and the circulating water are sufficiently mixed. Otherwise, the measured electrical conductivity may be unstable. Therefore, in the present embodiment, the comparison with the first and second reference values below is compared with the measured average value of electrical conductivity.

  Specifically, when the control unit 70 acquires the electrical conductivity Sm measured by the electrical conductivity measuring unit 61, the control unit 70 acquires a measured value every predetermined time by a built-in timer or the like, and acquires each measured measurement. The value was temporarily stored, and when the acquired measured values reached a predetermined number, the average value of the acquired numerical values was calculated, and this average value was used as the electrical conductivity Sm of the circulating water.

(3-1) Initial state A state in which the circulating water is not exchanged, that is, the control means 70 controls the electromagnetic on-off valves SV1 and SV2 provided in the water supply circuit 50 and the drain circuit 33. In the initial state where no signal is output, the normally closed electromagnetic on-off valves SV1 and SV2 are in a state where both the water supply circuit 50 and the drain circuit 33 are closed (see FIG. 1). It is in an undisclosed state.

  Note that the water level of the circulating water in the separator receiver tank 20 is adjusted so as to reach the intermediate position Lm by a water level adjusting mechanism (not shown). In this state, the control means 70 controls the lower limit position Ll of the level switch 62 and the intermediate position Lm. A detection signal from the switch at the position Lm is received (T0 in FIG. 3).

(3-2) Stage 1 From the initial state above, as the water-circulation compressor 1 performs the compression work by sucking outside air, the amount of impurities such as metal ions in the circulating water increases. Conductivity increases.

  When the electrical conductivity Sm measured by the electrical conductivity meter 61 becomes equal to or greater than a predetermined first reference value Ss1, and the control means 70 determines this, it outputs a control signal to the electromagnetic on-off valve SV1. Open (T1 in FIG. 3). As a result, water supply is started in the circulation system via the water supply circuit 50 by opening the electromagnetic on-off valve SV1.

(3-3) Second Stage The water supply started in the first stage is performed until the water level in the separator receiver tank 20 reaches the predetermined upper limit position Lh. The output of the control signal for opening the electromagnetic on-off valve SV1 is maintained until it is detected that the water level in the separator receiver tank 20 has reached the predetermined upper limit position Lh.

  When the level switch 62 detects that the water level in the separator receiver tank 20 is the upper limit position Lh, the control means 70 that has received this detection signal closes the electromagnetic on-off valve SV1 of the water supply circuit 50 and supplies water to the circulation system. At the same time, the electromagnetic on-off valve SV2 of the drain circuit 33 is opened to start draining the circulating water (T2 in FIG. 3).

(3-4) Third stage The drainage started in the second stage is performed until the water level in the separator receiver tank 20 reaches a predetermined lower limit position Ll. Until it is detected that the water level in the separator receiver tank 20 is at the predetermined lower limit position L1, the output of the control signal for opening the electromagnetic on-off valve SV2 is maintained.

  When the level switch 62 detects that the water level in the separator receiver tank 20 is at the lower limit position L1, the control means 70 closes the electromagnetic on-off valve SV2 of the drain circuit 33 and stops draining from the circulation system. Then, the electromagnetic on-off valve SV1 of the water supply circuit 50 is opened, and water supply to the circulation system is resumed (T3 in FIG. 3).

(3-5) Completion or continuation stage The water level in the separator receiver tank 20 rises due to the water supply started in the third stage described above, and the level switch 62 sets the water level in the separator receiver tank 20 to the predetermined intermediate position Lm. When it is detected that there is, the control means 70 determines whether or not the electrical conductivity Sm of the circulating water at this time is less than the second reference value Ss2.

  When it is determined that the electrical conductivity Sm measured by the electrical conductivity meter 61 is less than the second reference value Ss2, the electromagnetic on-off valve SV1 of the water supply circuit 50 is closed to stop the water supply, and the water supply / drainage to the circulation system is stopped. The process ends (T4 ′ in FIG. 3).

  On the other hand, if it is determined that the electrical conductivity Sm measured by the electrical conductivity meter 61 is greater than or equal to the second reference value Ss2, the control signal output to the electromagnetic on-off valve SV1 is continued and the water supply to the circulation system is continued ( T4 in FIG.

  Thereafter, the control means 70 repeats the operation after the second stage described above, and the water supply / drainage according to the aforementioned stage is repeated until the electrical conductivity Sm of the circulating water becomes less than the second reference value Ss2.

(3-6) Others In the above description, the control means 70 determines the electromagnetic on-off valves SV1. Although description has been made assuming that SV2 is operated, for example, one or both of the electromagnetic on-off valves SV1 and SV2 may be controlled with a predetermined time lag with respect to reception of a determination or detection signal.

BRIEF DESCRIPTION OF THE DRAWINGS The whole block diagram of the water circulation type compressor provided with the circulating water exchange apparatus of this invention. The flowchart of the water supply / drainage control by the method of this invention. The time chart which shows operation | movement of each part of the water exchange apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water circulation type compressor 10 Compressor main body 11 Discharge port 12 Water supply port 20 Separator receiver tank 31 Discharge circuit 32 Return circuit 33 Drain circuit 41 Radiator 42, 44 Water filter 43 On-off valve 45 Pure water device 50 Water supply circuit 61 Electrical conductivity measurement means (Electric conductivity meter)
62 Water level detection means (level switch)
70 Control means SV1, SV2 Electromagnetic on-off valve

Claims (6)

A compressor body that compresses the intake air together with the circulating water and a discharge port of the compressor body. The compressed air and the circulating water discharged from the compressor body are introduced to separate the compressed air and the circulating water. In a water circulation type compressor comprising a separator receiver tank for storing, wherein the circulating water circulation system is formed between the compressor body and the separator receiver tank,
When the electrical conductivity of the circulating water in the circulation system is equal to or higher than a first reference value set in advance, the supply water that introduces the supply water from the external water supply source that has passed through the deionizer into the circulation system; Alternately performing drainage to discharge a part of the circulating water in the circulation system,
Circulating water exchange method in a water circulation compressor, wherein the water supply and drainage is repeated until the electric conductivity of the circulating water becomes less than a second reference value set to a predetermined low value with respect to the first reference value. . 2. The circulating water exchange method in a water circulation compressor according to claim 1, wherein water supply and drainage to the circulation system is performed according to the following steps.
When the electrical conductivity of the circulating water is equal to or higher than the first reference value, a first stage of starting water supply to the circulating system;
A second stage in which when the water level in the separator receiver tank reaches a predetermined upper limit position, the water supply started in the first stage is stopped and drainage of the circulating water is started;
When the water level in the separator receiver tank reaches a predetermined lower limit position, the third stage of stopping the drainage started in the second stage and restarting the water supply to the circulation system;
When the electrical conductivity of the circulating water when the water level in the separator receiver tank reaches a predetermined intermediate position is less than the second reference value, the water supply started in the three steps is stopped and the water supply / drainage treatment is performed. A step of ending, or a step of continuing the water supply started in the third step and repeating the processing after the second step when the second reference value or more is reached.   The electrical conductivity of the circulating water is measured a predetermined number of times every predetermined time, and an average value of the electrical conductivity measured the predetermined number of times is obtained, and the obtained average value of the electrical conductivity is determined as the first and second standards. The circulating water exchange method in the water circulation type compressor according to claim 1, wherein the circulating water exchange method is compared with a value. A compressor body that compresses the intake air together with the circulating water and a discharge port of the compressor body. The compressed air and the circulating water discharged from the compressor body are introduced to separate the compressed air and the circulating water. In a water circulation compressor comprising a separator receiver tank for storing, and forming a circulation system of the circulating water between the compressor body and the separator receiver tank,
A water supply circuit comprising a deionizer and communicating between an external water supply source and the circulation system;
A drain circuit communicating with the circulation system;
Electrical conductivity measuring means for measuring the electrical conductivity of circulating water in the circulation system;
Opening and closing means for the water supply circuit and the drain circuit are provided,
The electrical conductivity measured by the electrical conductivity measuring means is measured by comparing with a first reference value set in advance and a second reference value set lower than the first reference value by a predetermined value. When the electrical conductivity is equal to or higher than the first reference value, the open / close means provided in the water supply circuit and the drain circuit are controlled to open and close to alternately supply water to the circulation system and partially drain the circulating water. And a control means 70 that repeats the water supply and drainage until the electrical conductivity of the circulating water becomes less than the second reference value. 5. The circulation in the water circulation type compressor according to claim 4, wherein water level detection means for detecting the water level in the separator receiver tank is provided, and the control means performs opening / closing control of the opening / closing means according to the following steps. Water exchange device.
The electrical conductivity measured by the electrical conductivity measuring means is compared with the first reference value, and when the measured electrical conductivity is equal to or higher than the first reference value, the opening / closing means of the water supply circuit is opened. One step,
A second stage of closing the open / close means of the water supply circuit and opening the open / close means of the drain circuit when the water level detecting means detects a water level at a predetermined upper limit position;
A third stage of closing the open / close means of the drain circuit and opening the open / close means of the water supply circuit when the water level detecting means detects a water level at a predetermined lower limit position;
When the water level detecting means detects a water level at a predetermined intermediate position, the electric conductivity measured by the electric conductivity measuring means is compared with the second reference value, and the measured electric conductivity is When it is less than the second reference value, the step of closing the water supply circuit opening and closing means to end the water supply and drainage, or when it is equal to or greater than the second reference value, the open state of the water supply circuit opening and closing means is maintained open. A stage where control after the second stage is repeated.   The control means acquires the electrical conductivity measured by the electrical conductivity measuring means a predetermined number of times at predetermined time intervals, calculates an average value of the acquired predetermined electrical conductivity, and calculates the average The circulating water exchange device in a water circulation compressor according to claim 4 or 5, wherein a value is compared with the first and second electric conductivities.

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