JP2003302306A - Inspection method for leakage of hydraulic circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To know necessity and level of emergency for maintenance of each single apparatus, for easiness and efficiency. <P>SOLUTION: Single apparatus such as a hydraulic cylinder 11, a direction control valve, etc., are connected to a hydraulic circuit. The hydraulic cylinder 11 is removed from the hydraulic circuit at connection ports p1 and p2. A hydraulic source 1 comprising a pressure regulating valve 4 and a flowmeter 5 is so connected to the connection port p1 of the hydraulic cylinder 11 as to supply an operation oil. While the operation oil is suppled to the hydraulic cylinder 11 from an oil tank 6 under a prescribed fluid pressure, a value of the flowmeter 5 is measured to judge oil leakage from the hydraulic cylinder 11. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak inspection method for a hydraulic circuit used in a drive device for opening and closing a water gate such as a dam gate.

[0002]

2. Description of the Related Art Conventionally, for example, as an opening / closing drive device for a water gate such as a dam gate, a hydraulic circuit for operating a hydraulic cylinder constructed so that a piston slides in the cylinder is used. This hydraulic circuit changes the position of the piston by controlling the supply / discharge of hydraulic oil circulating in the hydraulic circuit to / from the hydraulic cylinder, thereby extending / shortening the hydraulic cylinder. As the piston operates, the water gate is opened and closed.

In the above hydraulic circuit, after years of use, various trouble phenomena such as a decrease in the operating speed of the piston and an insufficient pressing force occur due to oil leakage. This phenomenon occurs due to deterioration of the sealing function due to wear / deterioration of the seal portion due to the operation of the hydraulic cylinder, scratches / wear on the sliding portion, and foreign matter mixed in oil. When such a problem occurs, conventionally, the single device that constitutes the hydraulic circuit is brought back to the manufacturer and disassembled, and each device is inspected for oil leakage, and the device that caused the problem Regarding the above, repairs and replacements were performed, and cleaning and other reassembly (overhaul) were taken.

[0004]

However, in the above-mentioned conventional method, it is cumbersome to carry out an overhaul of a single piece of equipment to its manufacturer because it requires a large amount of transportation, disassembly, and assembly work, which requires time and cost. There is a problem. In particular, when the hydraulic circuit is located in a remote area, it takes a long distance to carry the material, and it is necessary to pay attention to the transportation. In addition, there is a problem that it is not easy for the user to inspect the oil leakage by himself / herself because a technique therefor is required for disassembling / assembling the single device. In addition, it is not possible to identify the cause of the oil leakage on the appearance because it is a damage to the invisible part inside the single equipment, and even equipment with no defects is transported and disassembled and assembled, resulting in poor work efficiency. There is a problem.

Therefore, even if the hydraulic circuit has been in use for some years and has some operational problems, it becomes unusable due to a failure or accident, while worrying about the need for maintenance of each device. The current situation is to use it until that time. Such measures taken after a failure or accident may take time and costly to restore. In addition, since it is not possible to predict the device that caused the malfunction and the urgency of its maintenance, in some cases, a situation cannot be taken.

The present invention has been made in view of the above problems, and provides a leak inspection method for a hydraulic circuit that can be easily and efficiently performed, and that can determine the necessity of maintenance and the urgency of each piece of equipment. It is intended to be provided.

[0007]

The problems to be solved by the present invention are as described above, and the means for solving the problems will be described below.

According to a first aspect of the present invention, there is provided a leakage inspection method for a hydraulic circuit, wherein a single device such as a hydraulic cylinder and a directional control valve is connected,
A method for inspecting a leakage of a hydraulic circuit for operating a hydraulic cylinder, comprising disconnecting the single device from the circuit at a connection port, and connecting a hydraulic source having a pressure adjusting unit and a flow meter to the connection port of the single device. It is characterized in that a leak is judged by measuring a value of the flow meter while supplying a predetermined pressure liquid of hydraulic oil from the hydraulic pressure source to the single-unit device.

As a result, at the place where the hydraulic circuit is installed, with the hydraulic circuit kept as it is, the connection port of the single device for leak inspection is removed, and the hydraulic source is connected to this connection port.
Since it is possible to inspect the oil leakage of each single device by simply measuring the value of the flowmeter of the hydraulic power source, there is no need to transport the single device that constitutes the hydraulic circuit or disassemble and assemble the single device. . Therefore, the leakage inspection of the hydraulic circuit can be easily performed at a low cost in a short time. Further, it is possible to know the necessity of maintenance and the degree of urgency of each individual device, and to perform maintenance such as repair / replacement only on a defective single device, thus improving work efficiency.

According to a second aspect of the present invention, there is provided a hydraulic circuit leakage inspection method according to the first aspect, characterized in that the hydraulic fluid is from the hydraulic circuit.

As a result, since the same hydraulic oil as that used in the hydraulic circuit is used, there is no risk of mixing different types of oil.

According to a third aspect of the present invention, there is provided a hydraulic circuit leakage inspection method according to the first or second aspect, wherein the hydraulic fluid is adjusted to a predetermined temperature.

With this, the viscosity of the hydraulic oil can be made approximately the same as the environment in which the single device is manufactured, and the leak inspection can be reliably performed.

A leak inspection method for a hydraulic circuit according to a fourth aspect is characterized in that, in any one of the first to third aspects, the determination is made based on whether or not the flow meter is measured.

With this, it is possible to easily judge the oil leakage of the single equipment connected to the hydraulic circuit.

According to a fifth aspect of the present invention, there is provided a leakage inspection method for a hydraulic circuit, wherein in any one of the first to third aspects, the measurement value of the flow meter is compared with a reference value of the single piece device to make a determination. It is characterized by that.

With this, it is possible to easily determine the oil leakage of the single device connected to the hydraulic circuit. The reference value is a value measured when a single device is newly installed, or a value indicated by the manufacturer as an acceptance criterion.

According to a sixth aspect of the present invention, there is provided a hydraulic circuit leakage inspection method according to any one of the first to fourth aspects, wherein the single-piece device is a hydraulic cylinder.

This makes it possible to determine the sealing function of the sliding portion of the piston which constitutes the hydraulic cylinder, and the state of scratches and wear on the sliding portion.

According to a seventh aspect of the present invention, there is provided a leakage inspection method for a hydraulic circuit according to any one of the first to fourth and sixth aspects, wherein the single device is a check valve.

[0021] As a result, a scratch or damage is generated in the sliding portion of the check valve.
The state of wear can be determined. Further, it is possible to determine whether or not a foreign matter is caught in the sliding portion.

According to an eighth aspect of the present invention, there is provided a hydraulic circuit leakage inspection method according to any one of the first to fourth and sixth aspects, wherein the single device is a directional valve.

Thus, it is possible to determine the state of scratches and wear that have occurred at each switching position of the directional control valve.

According to a ninth aspect of the present invention, there is provided a hydraulic circuit leakage inspection method according to any one of the first to fourth and sixth aspects, wherein the single-piece device is a hydraulic pump.

With this, it is possible to judge the state of scratches and wear generated inside the hydraulic pump.

According to a tenth aspect of the invention, there is provided a hydraulic circuit leakage inspection method according to any one of the first to ninth aspects, wherein the hydraulic cylinder is used for opening and closing a water gate.

As a result, it is possible to prevent accidents due to leakage of the hydraulic circuit in floodgates such as dams and gates.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

In FIG. 1 and FIG. 2, a floodgate 3 arranged in a waterway.
1 shows a water gate opening / closing facility S that opens and closes 1 using a hydraulic cylinder 11 as a drive source, an opening / closing mechanism K that constitutes the facility, and a hydraulic circuit L thereof.

The opening / closing mechanism K is a water gate 31 pivotally supported so as to be swingable about a fulcrum p provided at the bottom of the water channel w.
And a hydraulic drive type hydraulic cylinder 11 installed on the back side thereof across a water gate 31 and a fixed portion 32 which is the bottom of the water channel. That is, when pressure oil is supplied to the hydraulic cylinder 11 and extension driving is performed, the sluice gate 31 can be placed in the upright posture to obtain the sluice gate closed state (solid line state in FIG. 1).
When the hydraulic cylinder 11 is drained, the hydraulic cylinder 11 is shortened by the pressing force of the water flow acting on the water gate 31 without requiring power, and the water gate 31 is almost recumbent (the state of the phantom line in FIG. 1). It is possible to obtain the sluice gate open state.

The hydraulic circuit L is a drive operation circuit for the hydraulic cylinder 11 that opens and closes the water gate 31. That is, in FIG. 2, the hydraulic circuit L includes a hydraulic pump 18 to which an electric motor 19 is connected, a hydraulic cylinder 11, a three-position switching type directional switching valve 17, a pilot check valve (check valve) 14, and a flow rate adjusting valve. It is configured to connect via 20.21.

The above hydraulic cylinder 11 has a cylinder chamber 1
A piston 12 is housed in the inside 3. The piston 12 is fixed to a head portion 12b that slides on the inner peripheral surface of the cylinder chamber 13, and a rod portion 12c that penetrates the cylinder chamber 13 and serves as an extension / shortening portion of the hydraulic cylinder 11.
In the outer peripheral portion of the head portion 12b, which is in sliding contact with the cylinder 13,
The inside of the cylinder chamber 13 is divided into a head side and a rod side,
A packing 12a serving as a seal portion is provided. The cylinder chamber 13 is provided with a connection port p1 on the head side and a connection port p2 on the rod side.

The hydraulic pump 18 is driven by an electric motor 19, and the directional control valve 17 has three positions (x).
Position, y position, z position). The direction switching valve 17 has connection ports p7 and p8 on the hydraulic pump 18 side. Further, the pilot check valve 14 includes a first check valve 15 and a second check valve 16, and opens and closes the circuit by pilot pressure. This pilot check valve 14 is used for the hydraulic pump 1.
It has connection ports p5 and p6 on the 8 side and connection ports p1 and p4 on the hydraulic cylinder 11 side. In addition, the flow rate adjusting valve 2
1 is both variable throttles 20a and 21a and check valves 20b and 2
It has a general structure in which 1b and 1b are connected in parallel.

The operation of the water gate 31 and the hydraulic circuit L at that time in the above structure will be described. In order to drive the hydraulic cylinder 11 to extend and swing the water gate 31 upward, the direction switching valve 17 is switched to the x position. Then, the pressure oil discharged from the hydraulic pump 18 becomes the first check valve 15
Through the connection port p5 to the connection port p3, and the flow rate adjusting valve 2
0, and is supplied to the cylinder chamber 13 of the hydraulic cylinder 11 from one connection port p1. At the same time, the hydraulic oil discharged from the connection port p2 of the hydraulic cylinder 11 passes through the flow rate adjustment valve 21, passes through the second check valve 16 from the connection port p4 to the connection port p6, and is discharged. In this way
The piston 12 is extended.

Next, the direction switching valve 17 is switched to the z position. Then, the water gate 31 naturally descends and oscillates due to the water pressure acting on it, and the hydraulic cylinder 11 on which the piston 12 is pushed moves in a shortened manner.
The oil in 3 is discharged through the flow rate adjusting valve 20 and the first check valve 15. At this time, the hydraulic pump 18 is stopped, but even if it is driven, there is no problem in causing the water gate 31 to naturally swing down.

When the direction switching valve 17 is switched to the y position (intermediate position), the state of the hydraulic cylinder 11 at that time is maintained. As described above, the position of the piston 12 is changed by controlling the supply and discharge of the hydraulic oil circulating in the hydraulic circuit L to and from the hydraulic cylinder 11.
Stretches and shortens. With the operation of this piston 12,
The opening / closing drive of the water gate 31 is performed.

Next, a method for inspecting oil leakage of each of the individual devices (hydraulic cylinder 11, pilot check valve 14, directional control valve 17, hydraulic pump 18) connected to the hydraulic circuit L will be described.

For the above inspection, the hydraulic power source 1 is used as shown in FIG. This hydraulic power source 1 constitutes a hydraulic circuit from an oil tank 6 to a connection port 7 via a hydraulic pump 2 connected to an electric motor 3, a pressure adjusting valve (pressure adjusting portion) 4, and a flow meter 5 in this order. is doing.

In the above-described structure, when the hydraulic pump 2 is driven by the electric motor 3 in the hydraulic power source 1, the hydraulic oil is sucked from the oil tank 6 and flows out from the connection port 7. At this time,
The hydraulic oil is made into a predetermined pressure liquid by the pressure regulating valve 4, and the amount of hydraulic oil flowing out from the connection port 7 is measured by the flow meter 5. It is preferable that the hydraulic oil injected into the oil tank 6 be the hydraulic oil of the oil tank 22. Also, the connection port 7
It is preferable that the hydraulic oil discharged from the tank is adjusted to a predetermined temperature. For example, a heating means such as a heater may be provided near the oil tank 6 to heat the hydraulic oil, or the hydraulic oil may be circulated in the hydraulic source 1 before being discharged from the connection port 7 so that the temperature of the hydraulic oil is increased in advance. May be raised.

(Hydraulic Cylinder) An oil leak inspection method for the hydraulic cylinder 11 will be described. The oil leak inspection of the hydraulic cylinder 11 connected to the hydraulic circuit L is performed by the hydraulic circuit A1 shown in FIG. The hydraulic circuit A1 is configured such that the connection port p1 of the hydraulic cylinder 11 is connected to the hydraulic power source 1 via the hydraulic pipe 23.

First, the hydraulic cylinder 11 is disconnected from the hydraulic circuit L at the connection port, and the connection port p1 is connected to the hydraulic pipe 23.
Via the connection port 7 of the hydraulic power source 1. Then, the hydraulic pump 2 is driven by the electric motor 3, and the value of the flowmeter 5 is measured while the hydraulic oil is supplied from the hydraulic source 1 to the hydraulic cylinder 11 by the pressure adjusting valve 4 with a predetermined pressure liquid.

At this time, the packing 12a of the piston 12
If the sealing function of 1 is effectively functioning, the supply of hydraulic oil from the hydraulic power source 1 is stopped and the flow rate is not measured by the flow meter 5. However, if the packing 12a is deteriorated or damaged such as scratches or wear, the hydraulic oil will pass through this portion,
The hydraulic oil is continuously measured by the flow meter 5. In this way, it is possible to determine the oil leak in the hydraulic cylinder 11 based on whether or not the flow meter 5 of the hydraulic power source 1 has been measured.

(Pilot Check Valve) An oil leak inspection method for the pilot check valve (check valve) 14 will be described. The oil leak inspection of the pilot check valve 14 is performed by the hydraulic circuit A2 shown in FIG. This hydraulic circuit A2
The connection port p3 of the pilot check valve 14 is the hydraulic pipe 2
It is configured to be connected to the above hydraulic power source 1 via 3.

First, the pilot check valve 14 is disconnected from the hydraulic circuit L at the connection port, and the connection port p3 is connected to the connection port 7 of the hydraulic source 1 through the hydraulic pipe 23. Then, the hydraulic pump 2 is driven by the electric motor 3, and hydraulic fluid is supplied from the hydraulic pressure source 1 to the pilot check valve 14 and the pressure adjusting valve 4
The value of the flow meter 5 is measured while being supplied with a predetermined pressure liquid at.

At this time, if the first check valve 15 of the pilot check valve 14 is functioning effectively, the supply of hydraulic oil from the hydraulic pressure source 1 is stopped and the flow rate is not measured by the flow meter 5. However, if the first check valve 15 is damaged, such as scratched or worn, or if dust contained in the hydraulic oil is caught,
The hydraulic oil passes through this portion, flows out from the connection port p5, and the flow meter 5 continues to measure the hydraulic oil. In this way, it is possible to determine the oil leak in the first check valve 15 depending on whether or not the flow meter 5 of the hydraulic power source 1 has been measured.
Similarly, the connection port p4 of the pilot check valve 14
Is connected to the connection port 7 of the hydraulic power source 1 via the hydraulic pipe 23, it is possible to determine the oil leakage of the second check valve 16.

(Direction Changeover Valve) An oil leak inspection method for the direction changeover valve 17 will be described. The oil leak inspection of the directional control valve 17 is performed by the hydraulic circuit A3 shown in FIG. In this hydraulic circuit A3, the connection port p7 of the direction switching valve 17 is
It is configured to be connected to the above hydraulic power source 1 via 3.

First, the direction switching valve 17 is disconnected from the hydraulic circuit L at the connection port, the connection port p7 is connected to the connection port 7 of the hydraulic power source 1 via the hydraulic pipe 23, and the direction switching valve 17 is connected. All of the pipes on the hydraulic cylinder 11 side are blind plugs 24
・ Set to 24. Then, the direction switching valve 17 is switched to the x position, the hydraulic pump 2 is driven by the electric motor 3, and the working oil is supplied from the hydraulic pressure source 1 to the direction switching valve 17 by the pressure adjusting valve 4 with a predetermined pressure liquid. Meanwhile, the value of the flow meter 5 is measured.

As described above, the direction switching valve 1 is connected from the connection port p7.
The hydraulic oil supplied to 7 is discharged from the connection port p8, and its flow rate is measured by the flow meter 5 of the hydraulic pressure source 1. At this time, if the directional control valve 17 is effectively functioning at the x position, the value measured by the flow meter 5 becomes a value close to the reference value of the directional control valve 17. However, if damage such as scratches or wear occurs at the x position, the hydraulic oil passes through this portion exceeding the reference value, and a value exceeding the reference value is measured. In this way, oil leakage at the x position of the directional control valve 17 can be determined based on the value measured by the flow meter 5 of the hydraulic power source 1. Similarly, the direction switching valve 17 can be switched between the y position and the z position to determine the oil leakage at each position.

(Hydraulic Pump) An oil leak inspection method for the hydraulic pump 18 will be described. The oil leak inspection of the hydraulic pump 18 is performed by the hydraulic circuit A4 shown in FIG. The hydraulic circuit A4 is configured such that the connection port on the hydraulic cylinder 11 side of the hydraulic pump 18 is connected to the hydraulic source 1 via the hydraulic pipe 23.

First, the hydraulic pump 18 is disconnected from the hydraulic circuit L at the connection port, and the connection port on the hydraulic cylinder 11 side is connected to the connection port 7 of the hydraulic power source 1 through the hydraulic pipe 23. Then, the hydraulic pump 2 is driven by the electric motor 3,
The hydraulic oil is supplied from the hydraulic source 1 to the hydraulic pump 18, and the pressure adjusting valve 4
The value of the flow meter 5 is measured while being supplied with a predetermined pressure liquid at.

As described above, the working oil supplied from the connection port on the hydraulic cylinder 11 side to the hydraulic pump 18 passes through the hydraulic pump 18, and the flow rate thereof is measured by the flow meter 5 of the hydraulic source 1. At this time, if the hydraulic pump 18 is effectively functioning, the value measured by the flow meter 5 becomes a value close to the reference value of the hydraulic pump 18. However, if the hydraulic pump 18 is damaged, such as damaged or worn, the hydraulic oil passes over the reference value, and a value exceeding the reference value is measured. In this way, it is possible to judge the oil leak of the hydraulic pump 18 from the value measured by the flow meter 5 of the hydraulic power source 1.

As described above, for example, the hydraulic circuit L is used as an opening / closing device for the water gate 31 such as a dam gate. This hydraulic circuit L changes the position of the piston 12 by controlling the supply and discharge of hydraulic oil circulating in the hydraulic circuit L to and from the hydraulic cylinder 11.
To stretch and shorten. With the operation of this piston 12,
The water gate 31 is opened and closed. This hydraulic circuit L
Is a large-scale device as a whole, and the sluice gate 3
Since the place where 1 is provided is often a remote place from the place where the hydraulic circuit L is manufactured, it is possible to easily and efficiently perform an oil leak inspection without carrying a single component device that constitutes the hydraulic circuit L. At the same time, it is desirable to know the necessity of maintenance and the urgency of each individual device.

In this respect, according to the leakage inspection method of the hydraulic circuit of the present embodiment, the single-piece device constituting the hydraulic circuit L is disconnected from the circuit at the connection port, and the pressure adjusting valve (pressure adjusting section) 4 and the flow meter 5 are connected.
By connecting the hydraulic source 1 having the and to the connection port of the single item device, and supplying hydraulic oil from the hydraulic source 1 to the single item device with a predetermined pressure fluid, the value of the flow meter 5 is measured to determine a leak. is there. As a result, there is no need to transport a single device that constitutes the hydraulic circuit or to disassemble and assemble the single device. Therefore, the leak inspection of the hydraulic circuit L can be easily performed at low cost in a short time. Further, it is possible to know the necessity of maintenance and the degree of urgency of each individual device, and to perform maintenance such as repair / replacement only on a defective single device, thus improving work efficiency.

In the present embodiment, the oil tank 6 of the hydraulic power source 1 is preferably the oil tank 22 of the hydraulic circuit L. Then, since the same hydraulic oil as that used in the hydraulic circuit L is used, there is no risk of mixing different types of oil. Further, the hydraulic oil supplied from the hydraulic pressure source 1 is preferably adjusted to a predetermined temperature. Then, the viscosity of the hydraulic oil can be made approximately the same as the environment in which the single device is manufactured, and the leak inspection can be reliably performed.

Further, in this embodiment, the hydraulic cylinder 11 and the pilot check valve 14 are judged by the presence / absence of measurement of the flow meter 5. As a result, it is possible to easily determine the oil leakage of the hydraulic cylinder 11 and the pilot check valve 14. Further, the directional control valve 17 and the hydraulic pump 18 judge by comparing the measured value of the flow meter 5 with the reference value of each individual device. As a result, the directional control valve 1
7. The oil leak of the hydraulic pump 18 can be easily determined.

Further, in this embodiment, the case where the hydraulic cylinder 11 is used to drive the opening and closing of the water gate 31 is described, and in the water gate 31 such as a dam or a gate,
It is possible to prevent an accident due to oil leakage of the hydraulic circuit L.

[0057]

As described above, according to the first aspect of the present invention, at the place where the hydraulic circuit is installed, the hydraulic circuit is left as it is, and the connection port of the single-unit device for leak inspection is removed. By connecting the hydraulic power source to the connection port and measuring the value of the flowmeter of the hydraulic power source, you can inspect the oil leak of each single device, so you can transport the single device that constitutes the hydraulic circuit or There is no need to disassemble and assemble. Therefore, the leakage inspection of the hydraulic circuit can be easily performed at a low cost in a short time. Further, it is possible to know the necessity of maintenance and the degree of urgency of each individual device, and to perform maintenance such as repair / replacement only on a defective single device, thus improving work efficiency.

According to the second aspect of the invention, since the same hydraulic oil as that used in the hydraulic circuit is used, there is no risk of mixing different types of oil.

According to the third aspect of the present invention, the viscosity of the hydraulic oil can be set to the same level as the environment in which the single device is manufactured, and the leak inspection can be reliably performed.

According to the fourth aspect of the invention, it is possible to easily determine the oil leak of the single-piece device connected to the hydraulic circuit.

According to the fifth aspect of the invention, it is possible to easily determine the oil leakage of the single-piece device connected to the hydraulic circuit.

According to the invention of claim 6, it is possible to judge the sealing function of the sliding portion of the piston which constitutes the hydraulic cylinder, and the state of scratches and wear generated in the sliding portion.

According to the seventh aspect of the present invention, it is possible to determine the state of scratches and wear on the sliding portion of the check valve. Further, it is possible to determine whether or not a foreign matter is caught in the sliding portion.

According to the eighth aspect of the present invention, it is possible to determine the state of scratches / wear that has occurred at each switching position of the directional control valve.

According to the ninth aspect of the invention, it is possible to determine the state of scratches / wear that has occurred inside the hydraulic pump.

According to the tenth aspect of the present invention, it is possible to prevent an accident at a floodgate such as a dam or a gate due to a leak of a hydraulic circuit.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic structure of a water gate opening / closing facility.

FIG. 2 is a circuit diagram of a hydraulic device using a hydraulic cylinder.

FIG. 3 is a circuit diagram when inspecting a hydraulic cylinder for leakage.

FIG. 4 is a circuit diagram when inspecting a check valve for leakage.

FIG. 5 is a circuit diagram when inspecting a directional control valve for leakage.

FIG. 6 is a circuit diagram when inspecting a hydraulic pump for leakage.

[Explanation of symbols]

1 hydraulic power source 4 Pressure adjustment valve (pressure adjustment section) 5 Flowmeter 6 oil tank 11 Hydraulic cylinder (single device)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G067 AA37 AA38 BB02 BB03 BB26                       CC03 DD04                 3H082 AA01 BB12 CC02 DA06 DA20                       DA42 DA46 DB03 DE08 EE20                 3H089 AA12 BB30 CC01 DA02 DB03                       DB34 DC05 FF06 GG02 JJ20

Claims (10)

[Claims] 1. A method for inspecting a hydraulic circuit for connecting a hydraulic cylinder, a directional control valve, and other single devices to operate the hydraulic cylinder, wherein the single device is disconnected from the circuit at a connection port to adjust the pressure. A hydraulic source having a section and a flow meter is connected to the connection port of the single-unit device, and hydraulic fluid is supplied to the single-unit device from the hydraulic source with a predetermined pressure liquid, and the value of the flow meter is measured to leak. A method for inspecting a leak in a hydraulic circuit, which comprises: 2. The leak inspection method for a hydraulic circuit according to claim 1, wherein the hydraulic oil is for the hydraulic circuit. 3. The hydraulic circuit leakage inspection method according to claim 1, wherein the hydraulic oil is adjusted to a predetermined temperature. 4. The hydraulic circuit leakage inspection method according to claim 1, wherein the determination is made based on whether or not the flow meter is measured. 5. The judgment is made by comparing the measurement value of the flow meter with a reference value of the single-unit device.
The leak inspection method for the hydraulic circuit according to any one of 3 to 3. 6. The leak inspection method for a hydraulic circuit according to claim 1, wherein the single device is a hydraulic cylinder. 7. The leak inspection method for a hydraulic circuit according to claim 1, wherein the single device is a check valve. 8. The leak inspection method for a hydraulic circuit according to claim 1, wherein the single piece device is a directional valve. 9. The leakage inspection method for a hydraulic circuit according to claim 1, wherein the single-unit device is a hydraulic pump. 10. The hydraulic circuit leakage inspection method according to claim 1, wherein the hydraulic cylinder is used to open and close a water gate.