JPH0850076A - Apparatus and method for diagnosing leakage of mechanical seal - Google Patents

Abstract

PURPOSE:To accurately measure and diagnose the initial leakage of a mechanical seal. CONSTITUTION:A seal liquid pressure adjusting valve 27, a seal independent valve 26 and an accumulator are arranged to the seal liquid supply system 16 in a mechanical seal of a form introducing a seal liquid under pressure and a seal independent valve 28 is arranged to a seal liquid discharge system and a seal liquid state measuring mechanism is arranged to either one of the supply system 16 and the discharge system 19. A control panel 30 recording the measuring data from the seal liquid state measuring mechanism and controlling the seal liquid pressure adjusting valve 27 and the seal independent valve 26 is arranged and the seal liquid 14 supplied to the mechanical seal is made independent by closing the seal independent valve 26 in a predetermined state and, after a predetermined amt. of the seal liquid is allowed to flow in the independent system, the pressure change of the seal liquid is measured to judge whether the seal liquid is leaked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a diagnostic method for diagnosing a leak state in a mechanical seal, particularly a mechanical seal of a type in which a seal liquid is press-fitted.

[0002]

2. Description of the Related Art In a mechanical seal, not only is a mechanical seal tightly sealed against an internal liquid (eg, paint) which should prevent leakage, but a seal liquid having a slightly higher hydraulic pressure than the internal liquid is press-fitted and circulated. The ones that prevent the leakage of liquid and try to cool at the same time are used. FIG. 4 shows an example thereof, in which the fixed ring 4 is fitted into the seal housing 3 attached to the portion where the rotary shaft 2 projects from the pump body 1 with a gap c left between the seal housing 3 and the rotary shaft 2. On the other hand, seal rings 5 and 6 are disposed facing the side sliding portions 4a and 4b of the fixed ring 4, and the seal ring 5 is provided in the recess 1a formed on one side surface of the pump body to rotate the rotary shaft 2 The seal ring 6 is fixed to the rotary shaft 2 on the atmosphere side.
It is slidably fitted to the retainer 7 fixed to the side surface and is pressed by the spring 8 against the side surface sliding portion 4b of the fixed ring 4.
Reference numerals 9 and 10 denote a seal liquid inlet and an outlet, which are formed by penetrating the housing 3 and the seal ring 6 in the radial direction from the outside of the seal housing 3 to the gap c. Is a seal liquid pressure pump 18 via a seal liquid pressure adjusting valve 27 as shown in FIGS.
And the delivery port 10 is pipe-connected to the seal liquid tank 17. In addition, 11, 12, and 13 are sealing members.

When the rotary shaft 2 is rotated to operate a pump (not shown) to be sealed, the seal rings 5 and 6 are respectively slid on the side surface 4 of the fixed ring 4.
Sliding in the circumferential direction while being in contact with a and 4b, this part is sealed. At the same time, the seal liquid 14 pressure-fed from the seal liquid pressure pump 18 via the seal liquid pressure adjusting valve 27 is press-fitted into the gap c via the seal liquid inlet 9.
Then, it flows out from the sealing liquid delivery port 10. As a result, while cooling the sliding portions 4a and 4b, the gap c
Is applied to the rotary shaft 2 and the seal ring 5 and the gap c ′ between the pump body 1 to prevent the leak, and the internal liquid 15 is leaked at a slightly higher pressure than the internal liquid (for example, paint) 15. To prevent. The leakage of the sealing liquid 14 is caused by the sliding portions 4a and 4b and the sealing members 12 and 13.
The leak of the internal liquid 15 is sealed by the sliding portion 4a and the sealing members 11 and 12.

By the way, the mechanical seal as described above also deteriorates the sliding portions 4a, 4b and the seal members 12, 13 due to long-term use, etc., and the seal liquid 14 in the gap c passes through the sliding portion 4a to form the above-mentioned material. The internal liquid 15 in the gap c ′ that enters the gap c ′ and mixes with the internal liquid 15
Enters the gap c through the sliding portion 4a and mixes with the seal liquid 14, the seal liquid 14 in the gap c flows out through the sliding portion 4b and the seal 13, and sometimes the seal liquid A phenomenon such as entering the clearance c ′ through the inlet 9 or the seal liquid outlet 10 or flowing out to the outside occurs.

Conventionally, in order to understand the above-mentioned phenomena in the mechanical seal, a flow rate measuring device is installed in each of the seal liquid supply system communicating with the seal liquid inlet 9 and the seal liquid discharge system communicating with the same outlet 10. However, of the two flow rate measuring devices that should show the same value, it was found that the value of the flow rate measuring device arranged in the seal liquid discharge system shows a value different from the value of the flow rate measuring device of the supply system, Although there is a method for grasping the occurrence, it is not suitable for detecting an initial defect with a small leak amount because the accuracy is generally low. On the other hand, JP-A-60-44844 and JP-A-63-27765.
As disclosed in Japanese Unexamined Patent Application Publication No. JP-A-2003-264, there is one that tries to catch the leakage of the internal liquid or the seal liquid with a pressure gauge.

[0006]

However, in the one disclosed in the above-mentioned publication, the pressure of the leaking internal liquid or the seal liquid is measured, so that the leakage amount is small in a normal pressure gauge. Early leaks are difficult to detect, and the use of high-accuracy pressure gauges can raise the cost of the mechanical seals to an economically unbearable level. Further, the leak detection means for the sealing liquid using the pressure gauge described in the above publication can only detect the leakage of the sealing liquid when the sealing liquid has leaked to some extent. It is not possible to accurately grasp the amount. The present invention has been invented with the object of providing a mechanical seal leakage diagnosing device and a diagnosing method capable of accurately measuring and diagnosing the initial leakage of a mechanical seal without significantly increasing the cost.

[0007]

SUMMARY OF THE INVENTION To solve the above-mentioned problems, a leakage diagnosing device and method for a mechanical seal according to the present invention include a seal liquid pressure system for a seal liquid supply system in a mechanical seal in which a seal liquid is press-fitted. An adjustment valve, a seal independent valve, and an accumulator are provided, and a seal independent valve is provided in the seal liquid discharge system, and a seal liquid state measuring mechanism is provided in one or the other of the supply system and the discharge system. Along with, a control panel for recording measurement data from the seal liquid state measuring mechanism and controlling the seal liquid pressure adjusting valve and the seal independent valve is installed. 1 and the supply system of the seal liquid in the mechanical seal of the type in which the seal liquid is press-fitted,
A seal liquid pressure adjusting valve, a seal independent valve, and an accumulator are provided, and a seal independent valve is provided in the seal liquid discharge system.These independent valves are connected to each other through a seal liquid circulation mechanism, and a seal is provided. A liquid state measuring mechanism is arranged in one or the other of the supply system and the discharge system, and further, measurement data from the seal liquid state measuring mechanism is recorded, and the seal liquid pressure adjusting valve, the seal independent valve and the A second invention relating to a leakage diagnosing device for a mechanical seal, which is characterized in that a control panel for controlling a circulation mechanism is installed, and a seal liquid supply system and a discharge system for the mechanical seal of a type in which a seal liquid is press-fitted. By configuring the mechanical seal as an independent system by closing the seal independent valve provided,
The seal liquid supplied to the mechanical seal is closed in a predetermined state by closing the seal independence valve and flown into the independent system by a predetermined amount, and then the change in the seal liquid pressure is measured to determine whether the seal liquid leaks or not. A third invention relating to a leakage diagnosis method for a mechanical seal, characterized in that the amount and the necessity of alarm are evaluated and judged, and a supply of the sealing liquid to a group of a plurality of mechanical seals in which the sealing liquid is press-fitted. A seal liquid pressure adjusting valve, a seal independent valve and an accumulator are provided in the system, and a seal independent valve is provided in the seal liquid discharge main system of the group, and a seal liquid state measuring mechanism is provided in the supply main system and It is installed on one side or the other side of the discharge main system, records the measurement data from the seal liquid state measuring mechanism, and controls the seal liquid pressure adjusting valve and the seal liquid. A fourth invention relating to a leakage diagnosing device for a plurality of mechanical seals, which is characterized in that a control panel for controlling an independent valve is installed, and a supply of the seal liquid to a group of a plurality of mechanical seals in which the seal liquid is press-fitted. This system is equipped with a seal fluid pressure adjusting valve, a seal independent valve, and an accumulator, and a seal fluid discharge valve for this group.The seal independent valve is installed in each system, and a circulation mechanism is provided between the two independent valves. And the seal liquid state measuring mechanism is disposed on one or the other of the supply main system and the discharge main system, recording the measurement data from the seal liquid state measuring mechanism, and the seal liquid pressure adjusting valve. And a control panel for controlling the seal independent valve, which is a fifth invention relating to a leakage diagnosing device for a plurality of mechanical seals. Consisting of.

[0008]

[Operation] According to the leakage diagnosing device and the diagnosing method of the mechanical seal of the present invention having the above-mentioned configuration, if the seal fluid pressure pump is operated and the rotary shaft of the pump to be sealed is rotated to operate the mechanical seal. Checking the hydraulic pressure of the seal liquid sent to the mechanical seal on condition that the first and second independent valves are opened so as to pass through the supply system and the discharge system, and if it is out of the predetermined pressure, the control panel Adjust the seal liquid pressure adjustment valve to bring the pressure of the seal liquid to a predetermined pressure. Next, the first and second independent valves are closed by the control panel, which makes the mechanical seal independent, and the accumulator or circulation pump keeps or adjusts the hydraulic pressure on the seal liquid inlet side of the mechanical seal to a predetermined value. Circulate in this condition, measure changes in seal fluid pressure and seal fluid temperature within a predetermined time, compare with the set value, the current state of the mechanical seal, that is, if there is leakage, if any, what is that amount? Moderately, whether or not there is a temperature rise, etc. are measured, evaluated, and judged, and OK and NG are judged. If NG, an alarm is issued, for example.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. 1 to 7. M, M-1, M-2 ... Are mechanical seals shown in FIG. The sealing liquid tank 17
Is connected to a seal liquid pressure pump 18 which is in communication with the seal liquid, and the seal liquid outlet 10 is connected to the seal liquid tank 17 by a seal liquid discharge system 19. 20, 20-1,
Reference numeral 20-2 is a diagnostic device of the present invention, and in the example shown in FIGS. 1 and 6, a supply system branched from the supply main system 21 and the discharge main system 22 for each mechanical seal M, M-1, M-2 ... 16 and the discharge system 19. The diagnostic device 20, 20
1, 20-2, ..., As represented by 20 in FIG. 1, seal liquid state measurement is performed on the supply system 16 of the mechanical seal M in order from the side closer to the seal liquid inlet 9 of the seal M. A pressure gauge 23 as a mechanism, a pressure sensor 24, an accumulator 25, a first independent valve 26, and a seal fluid pressure adjusting valve 27 are arranged, and a discharge system 19 of the mechanical seal M has a second independent valve. A liquefying valve 28 and a temperature sensor 29 as a seal liquid state measuring mechanism are provided, and the detection signals from the pressure sensor 24 and the temperature sensor 29 are recorded, and the seal liquid pressure adjusting valve 27 and the first A control panel 30 for issuing a control command is provided to the second independent valves 26 and 28.

A diagnostic device 20A of the present invention shown in FIG. 2 is a three-way type in which the first and second independent valves 26A and 2A are provided.
8A, both the independent valves 26A and 28A are connected by a pipe 32 via a circulation pump 31, and the first independent valve 26A and the seal hydraulic pressure adjusting valve 27 are connected.
The arrangement order of is changed and the circulation pump 31 is also connected to the control panel 30. Further, the diagnostic apparatus 20B of the present invention shown in FIG. 3 is a three-way type in which the first and second independent valves are provided and is provided with a pressure adjusting mechanism 33.
As B and 28B, both independent valves 26B and 28B are connected by a pipe 32 via a circulation pump 31, and
The circulation pump 31 and the pressure adjusting mechanism 33 are connected to the control panel 30.

Next, a method of diagnosing the presence or absence of the leakage of the mechanical seal M by the above-described leakage diagnosis device 20 of the present invention shown in FIG. 1 will be described with reference to the flowchart of FIG. First, after the start, it is checked in step 1 whether or not the seal liquid pressure pump 18 is operated, and in step 2, whether or not the rotary shaft 2 of the pump to be sealed is rotated and the mechanical seal M is operated. If so, go to step 3. If NO, the seal fluid pressure pump 18 is operated, the rotary shaft 2 is rotated, and the mechanical seal M is operated. Next, in step 3, it is checked whether or not the first and second independent valves 26 and 28 are open so as to pass through the supply system 16 and the discharge system 19, and if YES, the process proceeds to step 4 and NO If there is, a command is issued from the control panel 30 to open both the independent valves 26 and 28. In step 4, the hydraulic pressure of the seal liquid 14 sent to the mechanical seal M is read by the value indicated by the pressure gauge 23, or the pressure sensor 24
Checked by the detected value of, and it is out of the predetermined pressure (NO)
If there is, a command is issued by the control panel 30 to adjust the seal fluid pressure adjusting valve 27 to bring the pressure of the seal fluid 14 to a predetermined pressure. At this time, the detection value of the temperature sensor 29 is also checked and recorded. Next, at step 5, the first and second independent valves 26 and 28 are closed by the control panel 30 to thereby make the mechanical seal M independent. In step 6 (step 7 in FIG. 5), the accumulator 25 keeps the hydraulic pressure on the seal liquid inlet 9 side of the mechanical seal M at a predetermined value and supplements the seal liquid if necessary. Hold for a certain period of time, measure changes in the seal liquid pressure and the seal liquid temperature during that time, compare with the set value, the current state of the mechanical seal M, that is, whether there is leakage, if any, how much is it? Whether or not there is a temperature rise is measured, evaluated, and judged, and OK and NG are judged. If NG, an alarm is issued in step 7 (step 8 in FIG. 5).

The method for diagnosing the presence or absence of the leakage of the mechanical seal M by the leakage diagnosis apparatus 20A of the present invention shown in FIG. 2 differs from that shown in FIG. 1 in the following points. That is, in step 4 of FIG. 5, the pressure of the seal liquid 14 sent to the mechanical seal M is measured by the pressure gauge 2 as in the case of FIG.
The value indicated by 3 is read or the value detected by the pressure sensor 24 is checked, but if the pressure deviates from the predetermined pressure (NO),
The control panel 30 issues a command to issue a seal fluid pressure adjustment valve 2
7 is primarily adjusted, and the pressure of the seal liquid 14 is set to a predetermined pressure.
At this time, the detection value of the temperature sensor 29 is also checked,
Record. Further, in step 6 shown in FIG.
The circulating pump 31 is operated according to the command of
Is circulated in the independent system closed by the first and second independent valves 26A and 28A, and at this time, the seal liquid pressure adjusting valve 27 is adjusted to finally set the pressure of the circulating seal liquid to a predetermined pressure. .

The method of diagnosing the presence or absence of the leakage of the mechanical seal M by the leak diagnosing device 20B of the present invention shown in FIG. 3 is different from that shown in FIGS. 1 and 2 in the following points. That is, in step 4 of FIG. 5, when the fluid pressure of the seal fluid 14 sent to the mechanical seal M is out of the predetermined pressure (NO), the control panel 30 issues a command to make a primary adjustment of the seal fluid pressure adjusting valve 27. 2 is similar to that shown in FIG. 2, but in step 6, the circulation pump 31 is operated by the command from the control panel 30 to close the seal liquid 14 by the first and second independent valves 26B and 28B. The final adjustment of the pressure of the circulating seal liquid when circulating in the independent system is performed by setting the pressure adjusting mechanism 33 of the first and second independent valves 26B and 28B to a predetermined pressure.

The leakage diagnosis apparatus 20C of the present invention shown in FIG.
The mechanical seals M, M-1, M-2 are regarded as a group 34 to perform the leakage diagnosis, and the mechanical seals M, M-1, M- are provided from the seal liquid pressure pump 18 via the seal liquid supply system 16. 2, ... Supply main system 2
1 and the discharge main system 22 from the mechanical seals M, M-1, M-2, ... Through the seal liquid discharge system 19 to the seal liquid tank 17, and are installed in the leakage diagnosis device 20C. Although not shown, the supply main system 21 is provided with the above-described seal fluid pressure adjusting valve, the seal independent valve and the accumulator, and the discharge main system 22 is provided with the seal independent valve. For example, the both independent valves are connected to each other through a circulation mechanism, and a seal liquid state measuring mechanism is arranged on one or the other of the supply main system 21 and the discharge main system 22 to measure the seal liquid state. A control panel for recording the measurement data from the mechanism and controlling the seal fluid pressure adjusting valve and the seal independent valve is installed. In short, the leak diagnostic device 20C of the present invention may be configured by any of the leak diagnostic devices 20, 20A, and 20B shown in FIGS. The method for diagnosing the presence or absence of the leakage in the mechanical seals forming the mechanical seal group 34 by the leak diagnostic apparatus 20C of the present invention is as follows. Two
Same as the above-mentioned method by 0B, but at that time, the X and Y parts of the main supply system 21 and the main discharge system 22 are separated and X ′, Y ′.
If it is connected to, the presence or absence of leakage as the mechanical seal group 34, the leakage amount, etc. can be grasped.

[0015]

According to the present invention, a seal liquid pressure adjusting valve, a seal independent valve and an accumulator are sealed in the seal liquid supply system in a mechanical seal of a type in which a seal liquid is press-fitted, and a seal liquid discharge system is sealed. Each of the independent valves is provided, and the seal liquid state measuring mechanism is provided at one or the other of the supply system and the discharge system.
Record the measurement data from the seal liquid state measurement mechanism,
A first aspect of the present invention relates to a leakage diagnosing device for a mechanical seal, wherein a control panel for controlling the seal liquid pressure adjusting valve and the seal independent valve is installed, and the mechanical seal of a type in which a seal liquid is press-fitted. A seal liquid pressure adjusting valve, a seal independent valve, and an accumulator are provided in the seal liquid supply system, and a seal independent valve is provided in the seal liquid discharge system, and a seal liquid circulation mechanism is provided between the both independent valves. And a seal liquid state measuring mechanism is disposed in one or the other of the supply system and the discharge system, recording measurement data from the seal liquid state measuring mechanism, and the seal liquid pressure adjusting valve, Leakage diagnosis device for mechanical seal, characterized in that a control panel for controlling the seal independent valve and the circulation mechanism is installed. A second aspect of the present invention and a mechanical seal of a type in which a seal liquid is press-fitted, wherein the mechanical seal can be formed as an independent system by closing a seal independent valve provided in the seal liquid supply system and the discharge system. In addition, the seal liquid supplied to the mechanical seal is made independent by closing the seal independence valve in a predetermined state, and after flowing a predetermined amount in the independent system, the change in the seal liquid pressure is measured to check the leakage of the seal liquid. A third invention relating to a leakage diagnosis method for a mechanical seal, which is characterized by evaluating and determining presence / absence, leakage amount, necessity of alarm, etc., and sealing liquid for a group of a plurality of mechanical seals in which a sealing liquid is press-fitted. A seal liquid pressure adjusting valve, a seal independent valve, and an accumulator are installed in the main supply system of the Independent valves are provided, and a seal liquid state measuring mechanism is provided at one or the other of the supply main system and the discharge main system, and measurement data from the seal liquid state measuring mechanism is recorded. A fourth invention relating to a leakage diagnosis device for a plurality of mechanical seals, characterized in that a control panel for controlling the seal fluid pressure adjusting valve and the seal independent valve is installed;
Supply of seal liquid to a group of mechanical seals of the type that press-fits the seal liquid, a seal liquid pressure adjusting valve, a seal independent valve, and an accumulator are installed in this system.
Further, each of the group of seal liquid discharge main system is provided with a seal independent valve, the both independent valves are connected through a circulation mechanism, and the seal liquid state measuring mechanism is connected to the supply main system and the discharge line. A control panel, which is arranged on one side or the other side of the system, records measurement data from the seal liquid state measuring mechanism, and controls the seal liquid pressure adjusting valve and the seal independent valve. The invention relates to a leakage diagnosing device for a plurality of mechanical seals. Therefore, the pressure of the seal liquid on the supply side of the mechanical seals in a state where the supply system and the discharge system to the mechanical seal alone or to the group are closed and made independent. , By grasping the change in the temperature of the discharge side sealing liquid, the difference between the set pressure and temperature can be obtained with a relatively inexpensive device. Whether or not there is a leak of a single or a group of mechanical seals, and if there is a leak, the amount can be accurately and reliably grasped even if it is a small amount, and the mechanical seal can be easily evaluated and judged. In the case of the above, by connecting the independent valves through a seal liquid circulation mechanism, the supply system and the discharge system to the mechanical seal alone or to the group are closed as described above, and then the seal liquid is normally separated. Similarly, since the presence / absence of leakage and the amount of leakage can be grasped while flowing in the mechanical seal, there is an effect that the mechanical seal can be evaluated and judged more accurately. In the fourth and fifth inventions, the diagnostic device of the present invention is installed across the main supply system and the main discharge system of the seal liquid of a plurality of mechanical seal groups,
The presence / absence of leakage in the mechanical seal and the amount of leakage, if any, can be grasped on a group basis, and the mechanical seal can be evaluated and judged as a group. Therefore, there is an effect that a cheaper leakage diagnosis device can be obtained.

[Brief description of drawings]

FIG. 1 is an overall view showing an embodiment of a leakage diagnosing device for a mechanical seal of the present invention.

FIG. 2 is an overall view showing another embodiment of the leakage diagnostic device for the mechanical seal of the present invention.

FIG. 3 is an overall view showing another embodiment of the leakage diagnostic device for the mechanical seal of the present invention.

FIG. 4 is a sectional view showing an example of a mechanical seal to which the leakage diagnosing device for a mechanical seal of the present invention is applied.

FIG. 5 is a flow chart for explaining the operation of the leakage diagnosing device for a mechanical seal of the present invention.

FIG. 6 is a systematic diagram of an apparatus including a mechanical seal leakage diagnostic apparatus of the present invention for each mechanical seal.

FIG. 7 is a system diagram of an apparatus including a mechanical seal leakage diagnosis apparatus of the present invention in a group of mechanical seals. 1; Pump body 2; Rotating shaft 3; Seal housing 4; Fixed ring 5, 6; Seal ring 7; Retainer 8; Spring 9; Seal liquid inlet port 10; Seal liquid outlet port 11, 12, 13; Seal member 14; Seal liquid 15; Internal liquid 16; Seal liquid supply system 17; Seal liquid tank 18; Seal liquid pressure pump 19; Seal liquid discharge system 20, 20-1, 20-2, 20A, 20B, 20C;
Diagnostic device of the present invention 21; Seal liquid supply main system 22; Seal liquid discharge main system 23; Pressure gauge 24; Pressure sensor 25; Accumulator 26, 26A, 26B; First independent valve 27; Seal liquid pressure adjusting valve 28, 28A 28B; second independent valve 29; temperature sensor 30; control panel 31; circulation pump 32; pipe 33; pressure adjusting mechanism 34; mechanical seal group M, M-1, M-2; mechanical seal.

Claims (7)

[Claims] 1. A seal liquid pressure adjusting valve, a seal independent valve and an accumulator are provided in the seal liquid supply system in a mechanical seal of a type in which a seal liquid is press-fitted, and a seal independent valve is provided in a seal liquid discharge system. Each of them is provided with a seal liquid state measuring mechanism in one or the other of the supply system and the discharge system, recording measurement data from the seal liquid state measuring mechanism, and the seal liquid pressure adjusting valve and A leak diagnosing device for a mechanical seal, comprising a control panel for controlling the seal independent valve. 2. A seal liquid pressure adjusting valve, a seal independent valve, and an accumulator are provided in the seal liquid supply system in a mechanical seal of a type in which a seal liquid is press-fitted, and a seal independent valve is provided in the seal liquid discharge system. Each of the independent valves is connected to each other via a seal liquid circulation mechanism, and a seal liquid state measuring mechanism is provided in one or the other of the supply system and the discharge system, and the seal liquid state measuring mechanism is further provided. A leakage diagnosing device for a mechanical seal, characterized in that a control panel for recording the measured data from the above and controlling the seal fluid pressure adjusting valve, the seal independent valve and the circulation mechanism is installed. 3. A mechanical seal of a type in which a seal liquid is press-fitted, wherein the mechanical seal can be made an independent system by closing a seal independent valve provided in a supply system and a discharge system of the seal liquid. , The seal liquid supplied to the mechanical seal is closed in a predetermined state by closing the seal independence valve, and after flowing a predetermined amount into the independent system, the change in the seal liquid pressure is measured to determine whether the seal liquid leaks, A method for diagnosing leakage of a mechanical seal, which comprises evaluating and determining the amount of leakage and the necessity of alarm. 4. A seal liquid pressure adjusting valve, a seal independent valve and an accumulator, and a seal liquid discharge main line for a main seal liquid supply system for a plurality of groups of mechanical seals in which a seal liquid is press-fitted. A seal independent valve is provided in each system, and a seal liquid state measuring mechanism is provided in one or the other of the supply main system and the discharge main system, and the measurement data from the seal liquid state measuring mechanism is recorded. A leak diagnosing device for a plurality of mechanical seals, further comprising a control panel for controlling the seal fluid pressure adjusting valve and the seal independent valve. 5. A seal fluid supply valve for a plurality of groups of mechanical seals in which a seal fluid is press-fitted, a seal fluid pressure adjusting valve, a seal independent valve and an accumulator, and a discharge fluid for the seal fluid of the group. A seal independent valve is provided in each system, the two independent valves are connected to each other through a circulation mechanism, and a seal liquid state measuring mechanism is provided in one or the other of the supply main system and the discharge main system. Along with it, a control panel for recording measurement data from the seal liquid state measuring mechanism and controlling the seal liquid pressure adjusting valve and the seal independent valve is installed, and a plurality of mechanical seal leakage diagnosing devices are provided. . 6. The leak diagnosing device for a mechanical seal according to claim 1, 2, 3 or 4, wherein said seal independent valve is provided with a pressure adjusting mechanism. 7. The mechanical seal according to claim 1, wherein the seal liquid state measuring mechanism comprises a pressure measuring mechanism and / or a temperature measuring mechanism. Leakage diagnostic device.