JPH06129937A - Abnormality detection apparatus of mechanical seal - Google Patents

Abstract

PURPOSE:To detect the abnormality of a mechanical seal in a remote position before a fluid in large quantities is leaked by a method wherein a temperature sensor is mounted on the important part of the mechanical seal and it is connected to a signal output device which outputs an abnormality detection signal. CONSTITUTION:A temperature sensor 52 is mounted on the important part of a mechanical seal 11 mounted on a pump 13, i.e., on at least one part or on its neighborhood which is selected from a sliding and moving face, a fixation part, a shaft-passage-part inner circumferential wall to which the fixation part has been attached, a shaft- passage-port exit for a shaft sealing body or the like, and it is connected to a signal output device 60 arranged in a central control room or the like by an extension conductor 58 for themocouple use. An abnormality-detection set value for the signal output device 60 is set at a temperature which is a little higher than a prescribed operating temperature when the temperature of an internal fluid for the pump is higher than room temperature, and it is set at a low temperature when the temperature is lower than room temperature. When an abnormality is caused, the temperature sensor 52 generates an abnormal thermoelectromotive force, the output device 60 is actuated, an alarm buzzer 60 is sounded, an alarm lamp 66 is made to blink, and an operator in the central control room is informed that the abnormality has been caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical seal abnormality detecting device mounted on a shaft penetrating portion for sealing a rotary shaft penetrating the shaft penetrating portion of a sealed body, and more particularly to a mechanical seal abnormality detecting device. The present invention relates to a remote type abnormality detection device for a mechanical seal, which can easily detect an abnormality of the mechanical seal in a desired place far away from the shaft-sealed body to which the seal is attached, such as a central control room.

[0002]

2. Description of the Related Art Mechanical seals are widely used for axially sealing a rotary shaft that penetrates a shaft penetrating portion of a body to be sealed. For example, a centrifugal pump (also called a spiral wound pump) will be described as an example of the sealed body. In a centrifugal pump in which a pump shaft connected to a rotary drive device such as an electric motor rotates at a high rotation speed, a mechanical seal is generally used to seal the pump shaft with a pump casing. .

Various types of mechanical seals are used according to the type of the sealed object to be sealed and the shaft sealing conditions. In principle, as shown in FIG. 3, the mechanical seal 1 is used.
Reference numeral 1 denotes an end surface of an annular rotating portion 14 that rotates integrally with the rotating shaft 12 and a shaft penetrating portion 20 of the shaft-sealed body 16.
The rotary shaft 12 is axially sealed by slidingly sealing the rotary surface 12 with the end surface of the annular fixed portion 18 that is fixed to the sliding surface 44 as the rotary shaft rotates. The rotating portion 14 is pressed by the pressing mechanism 41 to form the sliding surface 44 that is in close contact with the fixed portion 18, and liquid-tightly seals the fixed portion 18 and the shaft penetrating portion 20. Therefore, a ring-shaped packing, for example, an O-ring 26 is interposed therebetween.

In the mechanical seal 11, the rotating portion 14 and the fixed portion 18 slide through the sliding surface 44 of the rotating shaft 12 during rotation, so that frictional heat is generated and the temperature of the components of the mechanical seal 11 is increased. Raise. In addition, the fluid handled by the sealed body (hereinafter referred to as internal fluid)
If the temperature of the mechanical seal 11 is high,
To raise the temperature of the components that make up. However, all the components of the mechanical seal 11 described above are precision-machined components and have a relatively low heat resistance temperature, and particularly, the heat resistance temperature of a synthetic resin component is low.

Therefore, when it is expected that the temperature of the mechanical seal 11 will rise and exceed the heat resistant temperature of the constituent parts, a flushing mechanism is provided in advance in the mechanical seal to cool the mechanical seal. The flushing mechanism generally divides a part of the internal fluid from the sealed body and removes foreign matter through the strainer 43.
Then, after cooling with a cooler 45 to lower the temperature, an internal fluid having a low temperature is introduced into the mechanical seal 11 from the flushing liquid inlet 46. The liquid introduced from the flushing liquid inlet 46 is called flushing liquid. The low-temperature flushing liquid is supplied to the rotating unit 14
The annular space 5 in the shaft penetrating portion 20 defined by
4 in the direction of arrow V to generate frictional heat
And the rotating part 14 to which the heat of the internal fluid is transferred is cooled.

The mechanical seal has a complicated shaft-sealing mechanism and is exposed to a high-temperature and high-pressure fluid, and in most cases, a corrosive fluid, and has a rotation speed of 3000 to 6000 rpm like a pump shaft of a centrifugal pump. Since the rotary shaft that rotates at high speed at the rotational speed is used under severe conditions such as sealing the shaft, various abnormalities or failures often occur in the mechanical seal. If the mechanical seal malfunctions and its shaft sealing function deteriorates, internal fluid may leak from the pump to the outside through the mechanical seal, and if the internal fluid is flammable, a fire may occur. . In addition, if the internal fluid is highly toxic, such as a fluid in which H ₂ S or Cl ₂ is dissolved, human injury may occur.

If the leakage of the internal fluid from the mechanical seal is left as it is, the mechanical seal will be greatly damaged and the mechanical seal needs to be replaced. Since the mechanical seal is an assembly of parts that require precision processing and is expensive, replacement of the mechanical seal is very expensive. Therefore, in factories that operate many pumps equipped with mechanical seals,
The operator regularly patrols the pump to monitor the pump, and if a fluid leak is found from the mechanical seal, the operator immediately takes a measure such as switching to a spare pump.

[0008]

By the way, in recent years, in petroleum refineries, petrochemical plants, chemical plants, etc., in order to improve the economical efficiency of operation and to cope with labor shortage, many There is a tendency to centrally manage devices and equipment. For example, a system has been adopted in which the operating status of each device or each device is centrally monitored in a central control room and remotely controlled from there. As a result, only a minimum number of operators are required to be installed in the factory at any given time. It is practically difficult for a small number of operators to regularly patrol the pump at short time intervals, and the patrol interval tends to be long. As a result, not only will the leakage be noticed more slowly and damage to the mechanical seal will increase, but in the worst case, the leaked fluid will ignite, resulting in a serious accident such as a fire, or leakage of highly toxic fluid. Because of this, the risk of human injury is increasing.

As a detection method replacing the operator's patrol visual inspection, a detection method by sound wave measurement and a leak detection method by a temperature sensor have been tried. The detection method by sound wave measurement is a method of detecting an abnormality of the mechanical seal by measuring a sound wave generated on the sliding surface of the mechanical seal. However, this method has a high rate of malfunction due to the sound waves generated by the rotating shaft and the shaft-sealed body itself, and in order to reduce the malfunction and improve the detection accuracy, frequent adjustments are required, and the method does not actually work. It has not yet been applied to the mechanical seal of the sealed body. On the other hand, the conventional leak detection method using the temperature sensor is to detect the liquid leaked from the mechanical seal by the temperature sensor, and the temperature sensor is provided in the vicinity of A shown in FIG.
It is intended to detect a temperature change due to the leakage of the internal fluid and detect that the internal fluid is leaking from the temperature change.

However, the leakage of the internal fluid from the mechanical seal means that the mechanical seal has been damaged to some extent, and in many cases, the mechanical seal needs to be replaced. Also, if the internal fluid is toxic or flammable, it is often too late to detect and deal with the leakage for safety reasons.Therefore, before the liquid leaks from the mechanical seal, the mechanical seal It is necessary to have a means for detecting the abnormality. However, the above-mentioned operator visual inspection method and the conventional leak detection method using a temperature sensor detect an abnormality of the mechanical seal only after a relatively large amount of fluid leaks from the mechanical seal. The discovery was extremely difficult.

In view of the above situation, an object of the present invention is to provide a device for detecting an abnormality of a mechanical seal from a remote place and detecting an abnormality of a mechanical seal before a relatively large amount of liquid leaks from the mechanical seal. That is.

[0012]

As a result of research on the cause of the abnormality of the mechanical seal, the present inventor has found that the cause can be roughly classified as follows. First, minute foreign matter, such as foreign matter contained in the internal fluid,
If it enters between the sliding surface of the fixed part and the rotating part, the sliding surface is easily damaged by foreign matter, and as a result, the internal fluid leaks through the damaged part due to the pressure inside the sealed body. is there. Secondly, the pressing mechanism that presses the rotating part against the fixed part deteriorates in function due to the high temperature and corrosive atmosphere, so that the contact on the sliding surface becomes poor and the internal fluid leaks through the gap. It is to be. Thirdly, the ring-shaped packing interposed between the shaft penetrating portion and the fixed portion is deteriorated and the sealing function is deteriorated, so that the internal fluid leaks from between the shaft penetrating portion and the fixed portion. is there. Fourth
In particular, internal fluid leaks between the rotating part and the rotating shaft. Fifthly, in a mechanical seal equipped with a flushing mechanism, the cooling function deteriorates due to a failure of the flushing mechanism, the temperature of the mechanical seal rises, and its component parts are damaged, so that the internal fluid leaks. is there.

On the other hand, when the mechanical seal is functioning normally, the temperature of the mechanical seal itself is irrespective of the change in the temperature of the internal fluid, and the temperature of the mechanical seal itself is naturally cooled or forced cooling such as quenching or flushing with a cooling fluid. It was confirmed that the temperature was maintained almost constant at the predetermined operating temperature. Further, in the case of the above-mentioned abnormality of the mechanical seal, it was confirmed as a result of many experiments that the temperature instantly rises or falls from the above-mentioned predetermined operating temperature at the location where the abnormality occurs. Generally, when the temperature of the internal fluid is high, the temperature rises, and when the internal fluid is a fluid such as LPG that vaporizes, the temperature drops.

Based on the results of the above research and experiments, in order to achieve the above object, the mechanical seal abnormality detecting device according to the present invention seals a rotary shaft that penetrates a shaft penetrating portion of a shaft-sealed body. A mechanical seal comprising a fixed portion and a rotating portion, wherein the fixed portion is formed in an annular shape having a shaft through hole and is liquid-tightly attached along the inner peripheral wall of the shaft through portion of the shaft-sealed body. And, the rotary shaft is rotatably pierced through the shaft through hole,
It is attached annularly around the shaft adjacent to the fixed part so as to form a sliding surface with the end face of the fixed part, and on the end face of the fixed part while rotating integrally with the rotating shaft in the shaft penetrating part. In order to detect the abnormality of the mechanical seal mounted on the shaft penetrating portion so that the sliding surface slides against the sliding surface, the sliding surface, the fixed portion, the inner peripheral wall of the shaft penetrating portion where the fixed portion is attached, and the sealed shaft are attached. It is equipped with a temperature sensor mounted at least at one location selected from the outlet of the shaft penetration portion of the body or in the vicinity thereof, and a signal output device for outputting an abnormality detection signal based on the output of the temperature sensor. Is characterized by.

The mechanical seal abnormality detecting device according to the present invention can be applied to any mechanical seal mounted on any sealed object, for example, a mechanical seal mounted on a pump, a stirrer, a centrifuge or the like. The temperature sensor used in the present invention is a commercially available temperature sensor such as a thermocouple thermometer or an electric resistance thermometer. Preferably, a thermocouple thermometer commonly referred to as a sheath thermocouple is used. A sheath thermocouple is made by inserting magnesia (MgO) and alumina (Al ₂ O ₃ ) into a protective tube into which a thermocouple has been inserted and then solidifying it. I have it. For example, those having a diameter of about 0.25 mm to 12 mm are commercially available, and the bendable radius of curvature is 1 to 5 times the diameter. Since the diameter is thin, it is suitable for local temperature measurement, has a small time delay of instruction, and has the advantage of not disturbing the temperature of the temperature-measuring object.

The mounting location of the temperature sensor should be individually selected according to the type of mechanical seal, but it is also possible to completely detect the abnormality by mounting all of the above locations. To attach the temperature sensor to the measurement location, make a hole extending to the vicinity of the measurement location in the shaft penetrating part and the mechanical seal component, or use a hole already formed for another purpose. And place the temperature measuring part of the temperature sensor near the measurement location.

The signal output device compares the temperature detected by the temperature sensor with the predetermined operating temperature of the mechanical seal, and if the difference is not less than the set value, outputs an abnormality detection signal indicating that an abnormality has been detected. The signal output device used in the present invention is a device configured by a known technique,
For example, it is installed in a central control room or the like. Input the abnormality detection signal from the signal output device to the desired device such as recording device, alarm device, automatic pump switching device, etc., record the abnormality occurrence, issue an alarm, and separate from the pump that detected the abnormality in the mechanical seal. It is also possible to switch to the pump automatically.

In the abnormality detecting device described above, in order to detect an abnormality of the mechanical seal provided with the flushing mechanism in addition to the fixed portion and the rotating portion, it is preferable that the shaft penetrating portion defined by the rotating portion be provided. Annular space, sliding surface,
A fixed part, an inner peripheral wall of the shaft penetrating part to which the fixing part is attached, and a temperature sensor mounted at least at one position selected from the outlet of the shaft penetrating part of the sealed body, or in the vicinity thereof,
And a signal output device that outputs an abnormality detection signal based on the output of the temperature sensor.

[0019]

[Function] When an abnormality occurs in the mechanical seal or when the internal fluid leaks through the mechanical seal,
As mentioned above, there is always a temperature change (difference between the specified operating temperature and the detected temperature, the same applies below). Therefore, place a temperature sensor in the above-mentioned location where temperature change easily occurs and detect the temperature change. Detects an abnormality in the mechanical seal. In a mechanical seal equipped with a flushing mechanism, if the flushing is not performed normally, the temperature of the flow path in which the flushing liquid flows changes from the normal temperature (predetermined operating temperature). It is possible to detect an abnormality of the flushing mechanism by detecting with.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory view showing a schematic cross section of a mechanical seal and an arrangement of temperature sensors attached to the mechanical seal in order to explain an embodiment of a mechanical seal abnormality detecting device according to the present invention. FIG. 2 is a system diagram of Embodiment 10 of the mechanical seal abnormality detection device according to the present invention. In FIGS. 1 and 2, the same parts as those in FIG. 3 are designated by the same reference numerals and the description thereof is omitted. The tenth embodiment is an apparatus for detecting an abnormality of the mechanical seal 11 attached to the pump 13. The mechanical seal 11 is attached to the shaft penetrating portion 20 of the pump casing 16 that is a sealed body, and seals the shaft 12 that penetrates the shaft penetrating portion 20. The liner 15 is fitted to the shaft 12, but for the sake of simplicity, the liner 15 will be referred to as the shaft 12 below. The mechanical seal 11 is attached in an annular shape in the circumferential direction of the shaft 12, and
The rotary unit 14 rotates integrally with the rotary unit 2 and a fixed unit 18 which is located adjacent to the rotary unit 14 on the side of the driving machine and fixed to the shaft penetrating unit 20 of the pump casing 16.

The annular flange 22 is used as the shaft penetrating portion 2.
The floating sheet 18, which constitutes a part of 0 and is annularly provided along the inner peripheral surface of the shaft hole of the flange 22, is formed as a fixed portion. The floating sheet 18 is formed of solid carbon, is liquid-tightly attached along the inner circumference of the flange 22 via an O-ring 26 made of Viton, and is provided so as to have a slight gap with the shaft. Shaft 1 in shaft through hole 28
2 is penetrated. Bushings 30 are provided along the inner circumference of the flange 22 at spaced positions outside the floating sheet 18, and the shaft penetrating portion 20 is provided so that foreign matter from the outside does not enter the mechanical seal 11.
The outlet 31 is substantially closed to protect the mechanical seal 11.

The rotating portion 14 is attached to the shaft 12 so as to be adjacent to the fixed portion 18 along the shaft 12 and to have a gap with the inner peripheral wall of the shaft penetrating portion 20. The components of the rotating portion 14 are a seal ring 32, a V ring retainer 34, a V ring 36, a drive collar 38, a coil spring 40, and a spring retainer 42, each of which is formed in an annular shape.

The seal ring 32 is formed in a ring shape from a hard material such as cemented carbide, and is fixed to the V ring retainer 34. The end face is floating sheet 18
A sliding surface 44 that is in close contact with the end surface of the floating seat 18 and that slides with the rotation of the shaft 12 is formed mutually with the end surface of the floating seat 18, and Shaft 1 rotating against
2 is shaft-sealed by the sliding surface 44 formed above. The V ring retainer 34 is sealed from the shaft 12 by a V ring 36 made of Teflon, and at the same time, the shaft 1
2, a pressing mechanism 4 including a spring retainer 42 fixed to No. 2 and a coil spring 40 having one end fixed to the spring retainer 42.
It is pressed toward the floating sheet 18 via the drive collar 38 by the spring force of 1. As a result, the seal ring 32 comes into close surface contact with the floating sheet 18 at the sliding surface 44.

All the components of the mechanical seal 11 described above are precision-machined parts and have a low heat resistant temperature, and particularly the O-ring 26 and the V ring 36 made of synthetic resin have a low heat resistant temperature. Therefore, when it is expected that the temperature of the mechanical seal 11 rises and becomes higher than or equal to the heat resistant temperature of the constituent parts due to frictional heat on the sliding surface or heat transfer from the internal fluid, as in this embodiment. The mechanical seal 11 is cooled in advance by providing the mechanical seal with the flushing mechanism shown in FIG. The flushing liquid introduced from the flushing liquid inlet 46 flows in the direction of the arrow V in the annular space 54 in the shaft penetrating portion 20 defined by the rotating portion 14, and the sliding surface 44 and the internal fluid in which frictional heat is generated are generated. The rotating part 14 to which heat is transferred is cooled.

Reference numerals 50a, 50b, 50c and 50d denote temperature sensor holes provided for mounting the temperature sensor 52, respectively. 50a is the temperature of the annular space 54 in the shaft penetrating portion 20 defined by the rotating portion 14, 50b is the temperature of the sliding portion 44, and 50c is the floating sheet 18 and the flange 22 to which the floating sheet 18 is attached. The temperature of the surrounding wall and 50d are
The mounting location of the temperature sensor 52 mounted to measure the temperature of the outlet 31 of the shaft penetrating portion 20 is shown as an example. The location should be selected according to the operating conditions of the mechanical seal 11.
The temperature sensor 52 may be attached to all of d. 5
0a, 50b, 50c and 50d may not be the same cross-section as shown in FIG. 1, but may be located in different cross-sections.
When the thickness is thick, a plurality of temperature sensors can be attached to a plurality of cross-sections at the same position as 50a, for example.

When the flow rate of the flushing liquid is reduced, its inflow is stopped, or its inflow temperature is raised, the temperature of the annular space 54 is changed, so that the temperature sensor 52 of 50a changes its temperature ( Difference from the specified operating temperature,
The same applies hereinafter) to detect the mechanical seal 1
Before the internal fluid leaks from No. 1, the abnormality of the flushing mechanism is detected. If the sliding state on the sliding surface 44 is abnormal, or if the internal fluid or flushing liquid flows out through the damaged portion of the sliding surface 44, the temperature of the sliding surface 44 changes. , 50b of the temperature sensor 52 detects an abnormality of the sliding surface 44 by detecting the temperature change.

When the seal between the floating sheet 18 and the flange 22 is impaired due to the deterioration of the O-ring 26, the internal fluid or flushing liquid flows therethrough, and the temperature changes. The sensor 52 detects an abnormality in the sealing between the floating sheet 18 and the flange 22 by detecting the temperature change. In any case, such as when the seal between the rotating portion 14 and the shaft 12 is damaged, when the sliding surface 44 is damaged, or when the seal between the floating sheet 18 and the flange 22 is damaged. Also, since the leaked internal fluid flows through the outlet 31 region of the shaft penetrating portion 20 and the temperature of the region changes, the temperature sensor 52 of 50d detects the temperature change and detects the leakage of the mechanical seal. can do.

The temperature sensor 52 used in this embodiment is
A sheath resistance thermometer manufactured by Okazaki Seisakusho Co., Ltd. After inserting the resistance thermometer (K (CA)) into a stainless steel tubular sheath having an outer diameter of 8.0 mm, magnesium oxide etc. Since it is formed by filling with an inorganic insulating material and there is no air layer inside, it has extremely high sensitivity and can be bent with a small radius of curvature. The temperature sensor 52 can be sealed from the outside by inserting the temperature sensor 52 into the bored temperature sensor hole 50 and screwing the temperature sensor 52 in the vicinity of the outlet of the temperature sensor hole 50. As shown in the system diagram of FIG. 2, the temperature sensor 52 is connected to a signal output device 60 provided in the central control room via a thermocouple extension lead wire 58.

The signal output device 60 converts a thermoelectromotive force of the thermocouple of the temperature sensor 52, which is transmitted through the extension wire 58, into an electric signal or a converter, and an output signal of the converter, for example, an output voltage. When the value is equal to or more than the set value, the output device outputs an abnormality detection signal.
The difference between the set value and the temperature detected by the temperature sensor 52 when the mechanical seal 11 is normal (the predetermined operating temperature at the temperature measuring point of the mechanical seal 11) is about 3 to 20 ° C, preferably about 5 to 10 ° C. It is set to fall within the range.
This is because if this difference is small, there is a risk of malfunction, and if it is large, it becomes difficult to detect the initial stage of occurrence of an abnormality. This allows
If the thermoelectromotive force of the thermocouple of the temperature sensor 52 increases,
When the output value of the converter becomes large and exceeds the set value, an abnormality detection signal is transmitted. The set value of the converter is variable and can be changed according to the predetermined operating temperature of the mechanical seal 11. The signal output device including the converter and the output device is a device having a conventional mechanism.

An alarm circuit 62 is connected to the signal output device 60, and the alarm circuit 62 is activated by the abnormality detection signal output from the signal output device 60 for each mechanical seal and for a temperature sensor hole of the mechanical seal. 50a
The alarm buzzer 64 is sounded and the alarm lamp 66 is flashed for each of the temperature sensors 52 mounted on the device 50d. Further, the signal output device 60 is connected to the recording / storing device 68. As a result, the abnormality detection signal is input to the recording / storing device 68, where necessary data such as the name of the pump in which the abnormality has been detected and the abnormality occurrence time are stored and printed as necessary.

It is also possible to connect the signal output device 60 to the pump automatic switching device 70 so as to automatically switch from a pump having a mechanical seal abnormality to another pump. A device provided with a pump is a so-called DC
S (Distributed Control System) or DDC (Dire
In the case of being controlled by a computer from the central control room by the ct Degital Control) method, the control device of the computer and the temperature sensor can be connected instead of the signal output device 60 described above.

The mechanical seal abnormality detecting device 10 of the present embodiment constructed as described above operates as described below. The temperature sensor 50 mounted at a predetermined location on the mechanical seal 11 measures a predetermined operating temperature of the mechanical seal under normal conditions and inputs a thermoelectromotive force corresponding to the temperature to the signal output device 60. When the temperature of the internal fluid of the pump is higher than the room temperature, if the abnormality detection setting value of the signal output device 60 is set to a setting temperature slightly higher than the predetermined operating temperature, the alarm will not be sent, so the central control room The operator who is monitoring can remotely confirm that the mechanical seal 11 is normal without going to the site. When the temperature of the internal fluid of the pump is lower than the normal temperature, or when the internal fluid is vaporized and its temperature is lowered like LPG, on the contrary, the set temperature is set lower than the predetermined operating temperature.

When the mechanical seal 11 has an abnormality, the temperature sensor 50 generates a thermoelectromotive force which is different from the normal state, and the signal output device 60 detects it and outputs an abnormality detection signal. The alarm buzzer 64 sounds and the alarm lamp 66 blinks. As a result, the operator monitoring in the main control room can immediately know from a remote place that an abnormality has occurred in the mechanical seal 11 before the leakage actually occurs, and it is possible to take necessary measures. Become. In an example in which the present embodiment is applied to a pump that transfers a fluid having a temperature of about 360 ° C, the signal generation set value of the signal output device 60 is set to 106 for a predetermined operating temperature of the mechanical seal 11 of 100 ° C. It was set to ° C. The temperature sensors 52 mounted on the mounting positions 50a and 50b of the mechanical seal 11 showed about 100 ± 3 ° C. when the mechanical seal 11 was normal, but when the flushing liquid was stopped, the temperature sensor 52 immediately The temperature rose to 140 ° C, the alarm buzzer 64 was sounded, and the alarm lamp 66 was made to blink.

In an example in which a pump for transferring a fluid having a temperature of about 310 ° C. is equipped with a mechanical seal having no flushing mechanism, a signal output device 60 is provided for a predetermined operating temperature of the mechanical seal of 98 ° C. The signal generation setting value of was set to 103 ° C. The temperature sensor 52 attached to the attachment location 50d of the mechanical seal 11 is about 98 ± 1 when the mechanical seal 11 is normal.
Although the temperature was shown as ° C, the temperature rose to 127 ° C almost immediately due to the leakage of the internal fluid, the alarm buzzer 64 was sounded, and the alarm lamp 66 was made to blink.

Although the mechanical seal mounted on the pump has been described above as an example, the mechanical seal abnormality detecting device according to the present invention can be applied to the mechanical seal mounted on any device, for example, a pump or an agitator. It can be applied to mechanical seals attached to centrifugal separators and the like.

[0036]

According to the present invention, the mechanical seal abnormality detecting device has at least one member selected from the group consisting of a sliding surface, a fixed portion, an inner peripheral wall of the shaft penetrating portion to which the fixing portion is attached, and an outlet of the shaft penetrating portion. A temperature sensor mounted at or near the location and a signal output device that outputs an abnormality detection signal based on the output of the temperature sensor are provided to detect the abnormality of the mechanical seal remotely, and The abnormality of the mechanical seal can be detected before the liquid leaks from the mechanical seal to the outside.
Since the temperature is detected inside the mechanical seal, even if a small amount of fluid leaks from the mechanical seal, it can be immediately detected, and the leakage of fluid harmful to the human body or dangerous flammable fluid is very early. It is possible to detect at the stage of. According to the present invention, since it is possible to detect an abnormality in the mechanical seal before the mechanical seal is damaged, it is possible to prolong the service life of the expensive mechanical seal.

[Brief description of drawings]

FIG. 1 is a temperature sensor arrangement diagram of an embodiment of a mechanical seal abnormality detection device according to the present invention.

FIG. 2 is a system diagram of an embodiment of a mechanical seal abnormality detection device according to the present invention.

FIG. 3 is a schematic view showing the principle of a mechanical seal.

[Explanation of symbols]

10 Example of Mechanical Seal Abnormality Detecting Device According to the Present Invention 11 Mechanical Seal 12 Rotating Shaft 13 Pump 15 Liner 14 Rotating Part 16 Shaft Sealed Body, Pump Casing 18, Fixed Part, Floating Sheet 20 Shaft Penetrating Portion 31 Exit 32 Seal Ring 40 Coil spring 43 Strainer 44 Sliding surface 45 Cooler 50 Temperature sensor hole 52 Temperature sensor 54 Annular space 58 Extension wire for thermocouple 60 Signal output device 62 Alarm circuit

Claims (2)

[Claims] 1. A mechanical seal, comprising a fixed part and a rotating part, for axially sealing a rotary shaft that penetrates a shaft penetrating part of a body to be sealed, wherein the fixing part has a shaft through hole. A ring-shaped member is liquid-tightly attached along the inner peripheral wall of the shaft penetrating portion of the shaft-sealed body, and the rotary shaft is rotatably pierced through the shaft penetrating hole. The fixing portion is annularly attached to the periphery of the shaft so as to form a sliding surface between the fixing portion and the end surface of the shaft, and rotates integrally with the rotary shaft in the shaft penetrating portion. In order to detect the abnormality of the mechanical seal attached to the shaft penetrating portion so as to slide the sliding surface with respect to the end surface of the An inner peripheral wall of the shaft penetration portion, and at least one location selected from the outlet of the shaft penetration portion of the shaft-sealed body or a temperature sensor mounted in the vicinity thereof, and an abnormality detection signal is output based on the output of the temperature sensor. A mechanical seal abnormality detecting device, comprising: 2. An annular space within the shaft penetrating portion defined by the rotating portion, and the sliding portion for detecting abnormality of a mechanical seal including a flushing mechanism in addition to the fixed portion and the rotating portion. A surface, the fixing portion, the inner wall of the shaft penetrating portion to which the fixing portion is attached, and a temperature sensor mounted at least at one place selected from the outlet of the shaft penetrating portion of the shaft-sealed body or in the vicinity thereof, The mechanical seal abnormality detection device according to claim 1, further comprising a signal output device that outputs an abnormality detection signal based on the output of the temperature sensor.