JPH0688764A - Pump leakage detector - Google Patents

Abstract

PURPOSE:To provide a highly reliable, inexpensive and remote-monitoring type pump leakage detector which can stand long use even under severe conditions. CONSTITUTION:A pump leakage detector 10 remotely detects the leakage of a fluid from a mechanical seal 16 where the fluid of room temperature or higher is exhausted and a pump 12 is shaft-sealed. The detector 10 is provided with a temperature sensor 14 and an alarming device 18 which is installed at an optional place apart from the sensor 14 and is connected with the sensor 14 so as to issue an alarm when the output from the sensor 14 becomes a set value or more. The sensor 14 is arranged adjacent to a pump shaft penetrated part 17 of the mechanical seal 16 in a manner that a temperature measuring part 15 of the sensor 14 may be brought into contact with the leaking fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump leakage detection device for detecting a leakage of pumping fluid, and more particularly to a pumping fluid from a mechanical seal that seals a pump discharging fluid at room temperature or higher. The present invention relates to a remote pump leakage detection device capable of easily confirming the presence or absence of leakage in a desired place far away from a pump, such as a central control room.

[0002]

2. Description of the Related Art Centrifugal pumps (also known as spiral pumps) are
By rotating an impeller at high speed in a pump casing through a pump shaft connected to a rotary drive device such as an electric motor, a large amount of fluid is transferred from one device to another device at a high discharge pressure. In order to seal a pump shaft rotating at a high rotation speed with a pump casing, a mechanical seal having a complicated shaft sealing mechanism is generally used. The type of pump to be sealed,
Various types of mechanical seals are used depending on the shaft sealing conditions, etc., but in principle, as shown in FIG.
By slidingly sealing between the end surface of the rotating ring B that rotates integrally with the shaft A and the end surface of the fixed ring D fixed to the shaft sealing box C attached to the pump casing, the pump shaft is sealed. Is going. The sliding surface E between the rotary ring B and the fixed ring D is generally inside the shaft sealing box C and shielded from the outside, as shown in FIG. In addition, F
Is a ring-shaped packing used to seal the fixed ring D when it is attached to the shaft sealing box C.

In the mechanical seal, when a minute foreign matter, for example, a foreign matter contained in the pumping fluid enters between the sliding end faces of the fixed ring and the rotating ring, the sliding surface is easily damaged by the foreign matter. Often, the pressure inside the pump causes the pumping fluid to leak through the damaged area. Moreover, once it starts to leak, the sliding surface becomes more and more damaged, and a large amount of fluid leaks. In oil refineries, petrochemical plants, or chemical plants where pumps often transfer flammable liquids heated above the flash point, static electricity will be generated if the flammable liquid heated above the flash point leaks from the mechanical seal. It is not rare to find a serious accident that easily ignites and causes a fire.

If the leakage of the pumping fluid from the mechanical seal is left as it is, the mechanical seal is greatly damaged as described above, 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 where many pumps equipped with mechanical seals are operating, conventionally, the operator regularly patrols the pumps and immediately monitors the pumps if a fluid leak is found from the mechanical seals. I was taking measures such as switching to another pump.

[0005]

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.

[0006] It is practically difficult for a small number of operators to periodically patrol the pump at short time intervals, and the patrol interval tends to be long. Therefore, not only the leakage becomes noticeable and the mechanical seal is greatly damaged, but in the worst case, the leaked fluid is ignited, and the risk of a serious accident such as a fire is increasing. Therefore, in petroleum refining plants, petrochemical plants, chemical plants, etc., it has long been possible to realize a pump leak detection device by remote monitoring, which is different from the conventional method in which an operator goes to the installation site of the pump and directly confirms it. It was strongly requested.

In order to realize a remote monitoring type pump leakage detecting device, the important condition is that the device is a highly reliable device which can be an alternative means for patrol monitoring of an operator. Second, it can withstand the harsh environment of high temperature corrosive atmosphere around the place where the pump is installed and can be used for a long period of time. It is a simple device. In order to meet the above demands and conditions, an object of the present invention is to provide an inexpensive remote monitoring type pump leakage detection device which is highly reliable and can be used in a harsh environment for a long period of time.

[0008]

The present inventor, after research and experiment, set up an image-based monitoring method, for example, an image pickup device using a CCD or the like in the vicinity of a mechanical seal of a pump, and constantly take an image. The method of displaying and monitoring with the image display device in the main control room not only requires an operator to monitor, but also that the imaging device installed in a high temperature corrosive atmosphere cannot be used in a short time. I found it. Recognizing that a highly reliable device that can withstand a harsh environment and that can be used as a substitute for the patrol of an operator must have a simple mechanism, the present invention was invented. It was.

In order to achieve the above object, the pump leakage detection device according to the present invention is a device for remotely detecting the leakage of fluid from a mechanical seal that seals a pump that discharges fluid at room temperature or higher. When the fluid leaks from the mechanical seal, the temperature sensor is placed in a position close to the pump shaft penetrating portion of the mechanical seal so that the leaked fluid may come into contact with the temperature sensor, and a desired temperature sensor separated from the temperature sensor. And an alarm device connected to the temperature sensor and configured to issue an alarm when the output of the temperature sensor is equal to or higher than a set value.

Although there are various types of mechanical seals, the present invention is applicable to any type of mechanical seal. In the case of a rarely used mechanical seal in which the sliding surface E between the rotary ring B and the fixed ring D is exposed to the outside as shown in FIG. 3B, on the extension surface of the sliding surface E Alternatively, the temperature measuring part of the temperature sensor is arranged close to the extension surface. There are no particular restrictions on the type of temperature sensor, but if you consider the installation conditions of the temperature sensor, which has a lot of harsh environments with high temperatures and corrosive atmospheres, a temperature sensor consisting of a thermocouple and a compensating lead wire inserted in the protective tube is recommended. preferable.

The temperature measuring portion of the temperature sensor is arranged in the vicinity of the pump shaft penetrating portion of the mechanical seal so that when the pumping fluid leaks from the mechanical seal, the surface of the mechanical seal is substantially orthogonal to the shaft from the pump shaft penetrating portion. This is because, when the fluid is leaked from the mechanical seal, the temperature measuring unit comes into contact with the leaked fluid if the temperature is set at such a location based on the fact that the fluid leaks out over the entire surface. Preferably, the temperature measuring section is installed at a position having a space of about 10 mm in the pump shaft penetrating section of the mechanical seal. It means that when the temperature measuring part is in contact with the pump shaft penetrating part, it measures the high temperature of the pump itself, and when it is too close, it also measures the temperature close to the temperature of the pump itself by heat radiation. , Because it may cause a malfunction. On the other hand, if it is too far away, the pumping fluid leaking from the mechanical seal does not come into contact with the temperature measuring unit, so the leak cannot be detected.

The alarm device is installed in a desired place separated from the pump installation place, for example, in a central control room. The alarm device used in the present invention is a known alarm device that has been used conventionally, and when an output value higher than a set value is input from the temperature sensor, an alarm buzzer sounds or an alarm lamp blinks. It is a device that can be operated.
In the present invention, it is not the display device of the temperature measured by the temperature sensor, but the alarm device that is designed to issue an alarm when the output value of the temperature sensor is equal to or higher than the set value. If it is a display device, it is necessary for the operator to constantly monitor it, but if it is an alarm device, it is possible for the operator to notice an abnormality even if it is not always monitored. Is.

[0013]

With the configuration described above, in the pump leakage detection apparatus according to the present invention, the temperature sensor normally measures a relatively low external temperature in the immediate vicinity of the mechanical seal and outputs the measured value to the alarm device. There is. If the alarm transmission setting value of the alarm device is set to a value equal to or higher than the output value at the above-mentioned relatively low temperature, the alarm will not be transmitted, so the operator in the main control room will not be able to leak fluid from the mechanical seal of the pump. You can remotely confirm that there is no such thing, without going to the field.

On the contrary, when there is a leakage of fluid from the mechanical seal of the pump pumping the fluid at room temperature or higher, the leaked fluid at a temperature of room temperature or higher comes into contact with the temperature measuring portion of the temperature sensor. Raise the temperature of. As a result, the temperature sensor inputs an output corresponding to the temperature, which is higher than the set value, to the alarm device to activate the alarm device,
Send an alarm. The alarm allows an operator monitoring in the central control room to immediately know remotely that fluid is leaking from the mechanical seal of a particular pump. As can be seen from the operation mechanism of the pump leakage detection device of the present invention described above, the pump leakage detection device according to the present invention also causes fluid leakage from the mechanical seal of the pump discharging the pumping fluid at a temperature lower than room temperature. It is also possible to detect.

[0015]

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 a system diagram of an embodiment of a pump leakage detection device according to the present invention. Figure 2 (a)
FIG. 2 is a perspective view showing a state in which a temperature sensor is mounted in the vicinity of a mechanical seal of a pump, and FIG. 2B shows a planar distance relationship between a temperature measuring portion of the temperature sensor and a shaft penetrating portion of the mechanical seal. It is an explanatory view shown. The pump leak detection device 10 of the embodiment detects the leakage of the pumping fluid from the mechanical seal of the target pump, and thus the mechanical seal 16A of the target pump 12A, 12B,
16B, temperature sensors 14A and 14B in which the respective temperature measuring units 15A and 15B are arranged, and a central control room for issuing a necessary alarm based on the output of the temperature sensor 14 and recording the alarm transmission. And an alarm device 18 installed in the. The alarm device 18 includes a temperature instruction alarm setter 21, a relay circuit 22, and a recording / storing device 28, which will be described later. The alarm device 18 sounds the alarm buzzer 24 and flashes the alarm lamp 26.

In this embodiment, the pump 12 is a pump for transferring high-temperature oil, which is generally called a so-called hot oil pump, and is, for example, 30 from a crude oil atmospheric distillation column of an oil refinery.
The bottom oil heated to a temperature of about 0 ° C.
For example, it means a pump or the like for transferring to a vacuum distillation column. Figure 2
As shown in FIG. 3A, the pump 12 is driven by an electric motor 13 via a pump shaft 19, and a mechanical seal 16 as shown in FIG. It is attached to 12. Although depending on the type of crude oil and the operating conditions of the crude oil atmospheric distillation column, the flash point of the bottom oil of the crude oil atmospheric distillation column is generally 80 ° C to 200 ° C. Therefore, if the bottom oil at a temperature of about 300 ° C. leaks from the pump to the outside via, for example, a mechanical seal, it is easily ignited by static electricity or the like, and a fire occurs.

The temperature sensor 14 used in this embodiment is
A commercially available thermocouple-type temperature sensor in which a K (CA) thermocouple is inserted into a sheath-type thermometer protection tube having a hollow cylindrical outer shape with a closed end, and is explosion-proof for use in a flammable gas atmosphere. It is a specification. The thermocouple has a function of generating a thermoelectromotive force according to the measured temperature, and K (CA)
There are types such as thermocouples using (chromel / alumel), T (CC) (copper / constantan) or J (IC) (iron / constantan), which can be selected according to the measurement accuracy and measurement temperature range. .

In this embodiment, as shown in FIGS. 2A and 2B, the temperature sensors 14A and 14B are provided with temperature measuring parts 15A and 15B at the tips of the mechanical seals 16A and 16B of the pumps 12A and 12B. Shaft penetrating portion 17A,
17B, and each of them is installed at a position having a distance of about 10 mm (d in FIG. 2A) with respect to the shaft penetrating portion 17. When the temperature measuring part is in contact with the shaft penetrating part, the high temperature of the pump 12 itself is measured,
Further, if they are too close to each other, the temperature close to the temperature of the pump 12 itself is also measured due to heat radiation, which causes a malfunction. On the other hand, if it is too far away, the hot oil leaking from the mechanical seal 16 of the pump 12 does not come into contact with the temperature measuring unit, so the leak cannot be detected.

Both terminals of the thermocouples of the temperature sensors 14A and 14B are connected to the terminals of a temperature indication alarm setting device 21 provided in the main control room through the pair of thermocouple compensating lead wires 20A and 20B, respectively. Respectively connected to.
The compensating lead wire is a thermocouple wire made of a material whose thermoelectromotive force characteristics are similar to those of a thermocouple wire in order to place the cold junction (reference contact) of the thermocouple at a location apart from the temperature measuring contact. It is an extension wire used as an extension of, and is commercially available. The temperature instruction alarm setter 21 converts the thermoelectromotive force of the thermocouple of the temperature sensor 14 transmitted through the compensating lead wire 20 into an electric signal, or an output signal of the converter, for example, an output voltage. It is composed of an alarm signal output device which outputs an alarm signal when the set value is exceeded. As a result, when the thermoelectromotive force of the thermocouple of the temperature sensor 14 increases, the output value of the converter increases and exceeds the set value, and the alarm signal is transmitted. It is desirable to be able to change the set value according to the temperature of the pumping fluid of the target pump 12. The converter and the alarm signal output device are devices having a commonly used mechanism.

The temperature instruction alarm setter 21 is a relay circuit 2
Connected to 2. The alarm signal output from the temperature instruction alarm setting device 21 is input to the relay circuit 22 as an alarm output contact signal for each of the temperature sensors 14A and 14B, and the alarm circuit of the relay circuit 22 is operated. Based on the alarm signal, the alarm circuit individually sounds the alarm buzzers 24A, 24B provided for the respective pumps 12A, 12B and individually flashes the alarm lamps 26A, 26B.

Further, the temperature instruction alarm setter 21 is connected to the recording / storing device 28 via a relay circuit 22. As a result, the alarm signal is simultaneously input to the recording / storing device 28 via the signal contact of the relay circuit 22, where necessary data such as the name of the pump that issued the alarm and the alarm transmission time are stored. It is printed according to. The crude oil atmospheric distillation apparatus itself provided with the hot oil pump is a so-called DCS (Distributed Control System) or DDC.
When the computer is controlled from the central control room by the (Direct Degital Control) method, the recording / storing device 28 is replaced with the relay circuit 22 to the recording / storing device of the computer. An alarm signal may be input.

The pump leakage detection device 10 of the present embodiment constructed as described above operates as described below. The temperature sensor 14A provided in the vicinity of the shaft penetrating portion 17A of the mechanical seal 16A of the pump 12A is
Under normal conditions, the temperature is the closest to the mechanical seal (approximately 40 ° C to 7 ° C).
0 ° C) is measured, and the thermoelectromotive force corresponding to the temperature is input to the temperature instruction alarm setter 21. If the alarm transmission set value of the temperature instruction alarm setter 21 is set to a value corresponding to 100 ° C., for example, the alarm is not transmitted. Therefore, the operator monitoring in the central control room uses the mechanical seal of the pump 12A. It is possible to check remotely that there is no leak of hot oil without going to the field.

When the bottom oil leaks from the mechanical seal 16B of the pump 12B, the leaked oil is about 300 ° C.
Hot oil contacts the temperature sensor 14
The protective tube of B is heated to a temperature higher than the ambient temperature, for example, 1
The temperature is raised to 00 to 200 ° C. Temperature sensor 14B
Generates a high thermoelectromotive force according to the temperature, operates the alarm signal output device of the temperature instruction alarm setting device 21, sounds the alarm buzzer 24B via the relay circuit 22, and causes the alarm lamp 26B to blink. As a result, the operator monitoring in the central control room can immediately know from a remote location that hot oil is leaking from the mechanical seal 16B of the specific pump 12B, and can take necessary measures. .

[0024]

According to the present invention, a temperature sensor mounted at a position close to a pump shaft penetrating portion of a mechanical seal, and a temperature sensor provided at a desired location apart from the temperature sensor and connected to the temperature sensor. By providing an alarm device and issuing an alarm when the output of the temperature sensor is equal to or higher than a set value, a remote monitoring type pump leakage detection device can be realized. Since the pump leakage detection device according to the present invention uses components whose reliability and durability have been established from the past, and has a very simple mechanism, it has high reliability and is harsh for a long time. It is an inexpensive device that can withstand various environments. With the pump leakage detection device according to the present invention, the presence or absence of leakage from the mechanical seal of the pump can be reliably and on-time grasped from a remote place, so that it is not necessary for the operator to visit, and the cost associated with damage to the mechanical seal is eliminated. It is possible to save money and prevent fire from occurring due to leakage of hot oil.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of a pump leakage detection device according to the present invention.

2 (a) is a perspective view showing a state in which the temperature sensor of the embodiment shown in FIG. 1 is provided at a position close to a mechanical seal of a pump, and FIG. 2 (b) is a measurement view of the temperature sensor. It is explanatory drawing which shows the planar distance relationship between a warm part and the shaft penetration part of a mechanical seal.

FIG. 3 (a) is an explanatory sectional view schematically showing an essential part of a mechanical seal, and FIG. 3 (b) is an explanatory sectional view of an essential part of another type of mechanical seal. .

[Explanation of symbols]

 10 Example of Pump Leakage Detecting Device According to the Present Invention 12 Pump 13 Electric Motor 14 Temperature Sensor 15 Temperature Measuring Section 16 Mechanical Seal 17 Pump Shaft 18 Alarm Device 19 Pump Shaft 20 Compensation Lead Wire 21 Temperature Indication Alarm Setting Device 22 Relay Circuit 24 Alarm Buzzer 26 Alarm lamp 28 Recording / storage device

Claims (1)

[Claims] 1. A device for remotely detecting leakage of the fluid from a mechanical seal that seals a pump that discharges fluid at room temperature or higher, wherein the fluid leaks from the mechanical seal when the fluid leaks. A temperature sensor having a temperature measuring portion arranged in a position close to the pump shaft penetrating portion of the mechanical seal so as to come into contact with the temperature sensor, and the temperature sensor is provided at a desired location apart from the temperature sensor and is connected to the temperature sensor. And a warning device for giving a warning when the output of the temperature sensor is equal to or higher than a set value.