JP6776049B2 - Water hammer prediction system and water hammer prediction method in piping - Google Patents

Description

The water hammer prediction system and the water hammer prediction method in a pipe according to the present application relate to a technique for predicting the possibility and location of a water hammer in a pipe such as a steam pipe.

Industrial plants may be equipped with a piping system that transfers steam generated by the boiler to the supply destination at high temperature and high pressure. When steam is liquefied in this pipe, drain (condensed water of steam) stays and the space for steam transfer is reduced, resulting in a decrease in steam transfer efficiency.

In order to avoid such a situation, a large number of steam traps are provided everywhere in the piping system. When the amount of drain water inside the steam trap reaches a certain level due to liquefaction, the built-in float floats to open the outlet of the steam trap and automatically drains the drain. The discharged drain is collected through a drain collection pipe and is generally reused by supplying water to the boiler again.

By the way, when a certain amount of drain is present inside the drain recovery pipe, a water hammer may occur. Water hammer is a phenomenon that occurs when drainage lumps collide with each other inside a pipe, and when this water hammer occurs, a sudden pressure change of 10 MPa or more may occur instantly inside the pipe. Therefore, if the water hammer is repeatedly generated, the joints and valves of the pipes at specific locations may be destroyed at once due to the accumulation of the influence of the impact, and a large amount of steam or high-temperature drain may be ejected.

In order to avoid such a problem caused by water hammer, a detection technique as disclosed in the patent document described later has been proposed. In this detection technology, a plurality of thread-like sensors are attached in the circumferential direction of a specific part of the pipe.

This sensor is attached to the pipe by applying tension without loosening, and has a structure that breaks when a force exceeding a certain tensile force is applied. When a water hammer is generated in a pipe, the impact causes the pipe to vibrate, so that a force exceeding a certain tensile force is applied to the thread-shaped sensor and the pipe breaks. Therefore, it is possible to detect that a water hammer has occurred in the vicinity of the sensor mounting location by visually recognizing the breakage of the sensor.

Japanese Unexamined Patent Publication No. 2012-68175

However, in the technique disclosed in the above-mentioned patent document, it is not possible to detect that a water hammer does not actually occur in the pipe, and it is not possible to predict the occurrence or location of the water hammer in advance. As mentioned above, since the occurrence of water hammer may break the piping and cause an accident, a technique for predicting the possibility of occurrence before the occurrence of water hammer is required as much as possible.

Therefore, the water hammer prediction system and the water hammer prediction method in the pipe according to the present application have a problem of solving these problems, and the pipe that can easily and surely predict the possibility and the location of the water hammer. The purpose is to provide a water hammer prediction system and a water hammer prediction method.

The water hammer prediction system in the piping according to the present application is
Main piping that fluid moves inside,
A connection pipe connected to the main pipe, in which the fluid moves from upstream to downstream inside and flows into the main pipe.
An on-off valve, which is provided on the connecting pipe and blocks or opens the movement of fluid.
A detection unit provided on the connection pipe on the upstream side of the on-off valve, which detects the state in the connection pipe in the vicinity and outputs a state signal indicating the state.
Based on the received status signal, it is determined whether or not the fluid on the upstream side of the on-off valve is in a predetermined dangerous state, and when it is determined that it is in a dangerous state, a control unit that performs water hammer forecast processing,
It is characterized by being equipped with.

In addition, the water hammer prediction method in the piping according to the present application is
Main piping that fluid moves inside,
A connection pipe connected to the main pipe, in which the fluid moves from upstream to downstream inside and flows into the main pipe.
An on-off valve, which is provided on the connecting pipe and blocks or opens the movement of fluid.
In the water hammer prediction method regarding the water hammer prediction system in the pipe equipped with
Detects the condition inside the connecting pipe near the connecting pipe on the upstream side of the on-off valve.
Determine if the fluid on the upstream side of the on-off valve is in a predetermined danger state and determine
When it is determined that it is in a dangerous state, water hammer forecast processing is performed,
It is characterized by that.

In the water hammer prediction system and the water hammer prediction method in the piping according to the present application, it is determined whether or not the fluid on the upstream side of the on-off valve is in a predetermined dangerous state, and when it is determined that the fluid is in a dangerous state, the water hammer Perform forecast processing. Therefore, it is possible to easily and surely predict the possibility and location of water hammer due to the fluid on the upstream side of the on-off valve becoming in a dangerous state.

It is a functional block diagram which shows one Embodiment of the water hammer prediction system and the water hammer prediction method in the pipe which concerns on this application. It is a figure which shows the content of the data table of the saturated steam table stored in the memory 7 shown in FIG. It is a figure which shows the content of the danger notification displayed on the monitor 8 shown in FIG. It is a figure for demonstrating the occurrence of a water hammer.

[Terminology in the embodiment]
The main terms shown in the embodiments correspond to the following components of the water hammer prediction system and the water hammer prediction method in the pipe according to the present application, respectively.
Steam, drain 2 ... fluid drain recovery pipe 10 ... main pipe drain connection pipe 12, 13, steam transport pipe 20 ... connection pipe steam trap 42, 43, 44 ... on-off valve temperature data / pressure data ... status signal sensor 32, 33, 34… Detection unit Saturation state… Danger state Control unit 6… Discrimination unit, control unit Danger notification… Water hammer forecast processing

[First Embodiment]
An embodiment of the water hammer prediction system and the water hammer prediction method in the pipe according to the present application will be described below. An industrial plant may be equipped with a piping system that transfers steam or the like generated by a boiler to a supply destination at high temperature and high pressure. In this embodiment, a water hammer generated in such a piping system is used. Taking an example, the technique related to the prediction will be illustrated.

(Explanation of the cause of water hammer)
First, as a premise, the cause of water hammer will be briefly explained. The causes of water hammer are not uniform, but the most common one is considered to be water hammer, which occurs when drains collide with each other due to rapid condensation of steam.

FIG. 4 is a diagram showing a connection portion between the drain recovery pipe 10 and the drain connecting pipe 11. High-temperature and high-pressure drain 2 generated in various parts of the pipe is collected and transferred into the drain recovery pipe 10 through a large number of drain connection pipes. By the way, when a high-temperature and high-pressure drain is exposed to a low-pressure atmosphere in various places, a flash steam (re-evaporated steam) 4 in which a part of the drain is vaporized is generated, and this flash steam 4 is also transferred together with the drain. As a result, as shown in FIG. 4A, the flush steam 4 transferred through the drain connection pipe 11 is also sent to the drain recovery pipe 10.

Since the temperature of the drain 2 flowing in the drain recovery pipe 10 decreases with the passage of time, when the high temperature flash steam 4 comes into contact with the cold drain 2, the flash steam 4 rapidly condenses due to heat dissipation and drains at once. As a result, the part where the flash vapor was present may temporarily become a state close to vacuum. Then, in this case, as shown in FIG. 4B, the surrounding drain is drawn into this space and collides with it, so that a water hammer is generated.

(Explanation of block diagram of system in this embodiment)
The block diagram of the system shown in FIG. 1 will be described. The steam transport pipe 20 transfers the high-temperature and high-pressure steam generated in the boiler (not shown) to each device in the plant. FIG. 1 exemplifies a heat exchanger 62, a hot air dryer 63, and a jacket kettle 64 as equipment for receiving steam transfer.

By the way, when steam is used in equipment such as a heat exchanger 62, a hot air dryer 63, and a jacket kettle 64, the latent heat in the heat energy of the steam moves to the object to be heated, and as a result, the steam liquefies and drains (steam). Condensed water) is generated. If this drain is excessively retained in the pipe, the steam supply efficiency will decrease, so it is necessary to discharge it to the outside.

Therefore, steam traps are provided everywhere in the piping system. The block diagram of FIG. 1 shows a steam trap 42 provided in the piping of the heat exchanger 62, a steam trap 43 provided in the piping of the hot air dryer 63, and a steam trap 44 provided in the piping of the jacket kettle 64. ing.

This steam trap is a type of on-off valve that shuts off or opens the movement of steam and drain inside. For example, when the amount of drain water inside the pipe reaches a certain level, the built-in float floats and opens the discharge port. However, it has a structure that automatically drains the drain. The drain discharged from the steam trap 42 receives the high-pressure momentum in the pipe and is discharged to the drain recovery pipe 10 through the drain connecting pipe 12. Similarly, the drain discharged from the steam traps 43 and 44 is discharged to the drain recovery pipe 10 through the drain connecting pipe 13.

The drain collected in the drain collection pipe 10 is collected in a drain tank (not shown) and reused. According to the flow of steam and drain in the entire piping system, the equipment side is upstream and the drain recovery pipe 10 side is downstream when viewed from each steam trap.

Here, sensors 32, 33, and 34 capable of directly or indirectly detecting the temperature and pressure in the pipe are installed in the immediate vicinity of each of the steam traps 42, 43, and 44. Each of the sensors 32, 33, and 34 has a wireless communication function and can transmit the detected temperature data and pressure data. Then, these data are received by the receiving unit 5, and the receiving unit 5 further transmits the data to the control unit 6. The control unit 6 includes a memory 7 and controls the display of the monitor 8.

(Explanation of system operation in this embodiment)
Next, the operation of the system in this embodiment will be described. In the present embodiment, when it is determined that the steam on the upstream side of each steam trap is saturated, it is predicted that a water hammer may be generated at a specific location due to the generation of flash steam, and a danger notification process is performed. I do. Since the locations where water hammer is likely to occur for each steam trap can be identified by measurement, experience, etc., the predicted locations for water hammer occurrence corresponding to each steam trap are stored in the memory 7.

In the example shown in FIG. 1, the water hammer occurrence prediction points P1 are associated and stored in the steam trap 42, and the water hammer occurrence prediction points P2 and P3 are associated and stored in the steam trap 43. Similar to the steam trap 43, the trap 44 is stored in association with the predicted water hammer occurrence locations P2 and P3. Regarding a specific steam trap, there may be only one predicted water hammer occurrence location, but there may be multiple locations. In addition, the water hammer may occur in a pipe outside the drain recovery pipe 10, such as the water hammer occurrence prediction point P2.

The specific processing of the system in this embodiment is as follows. First, the control unit 6 receives the temperature data and pressure data from the sensors 32, 33, and 34 via the reception unit 5. Here, the memory 7 of the control unit 6 stores a data table of the saturated steam table as shown in FIG. According to this data table, the control unit 6 determines whether or not the steam in the pipe at the detection points of the sensors 32, 33, and 34 is saturated.

For example, if the pressure data transmitted from a specific sensor is "200 kPa" and the temperature data from that sensor reaches "120.21 ° C", the control unit 6 will release steam in the piping at the measurement point of the sensor. Judge that it is saturated. The saturated steam table shown in FIG. 2 is a correspondence table between pressure and temperature based on pressure. However, a saturated steam table based on temperature is stored, and pressure corresponds to pressure based on temperature data. The saturation state can also be determined by whether or not the pressure value has been reached.

Now, suppose that the data transmitted from the sensor 33 indicates the saturated state of steam. As described above, regarding the steam trap 43 at the location where the sensor 33 is provided, the water hammer occurrence prediction locations P2 and P3 are associated and stored in the memory 7, so that the water hammer occurrence prediction locations P2 and P3 are water hammered. It can be determined that a hammer may occur.

Therefore, the control unit 6 gives a danger display signal to the monitor 8 to notify the danger. In the present embodiment, the content as shown in FIG. 3 is displayed on the screen of the monitor 8 as a danger notification. A plan view of the piping system is displayed on the monitor 8, and a mark K indicating that it is dangerous is displayed at the water hammer occurrence prediction points P2 and P3 on the piping. Further, the mark K can be colored with red or the like. Further, it is possible to blink the mark K, and at the same time, it is possible to emit an alarm sound such as a buzzer. Further, as the danger notification, it is possible to generate an alarm sound, lighting of a lamp, etc. not only on the screen of the monitor 8 but also at the corresponding site in the plant.

By processing the danger notification based on the possibility of water hammer occurrence and the prediction of the occurrence location, it is possible to take appropriate measures according to the situation such as interruption of work or evacuation by the worker at the location.

[Other Embodiments]
The water hammer prediction system and the water hammer prediction method in the pipe according to the present application are not limited to the system shown in the above-described embodiment, and other pipes as long as they relate to the prediction of water hammer generated in the pipe in which the fluid moves inside. It can also be applied to strains.

Further, in the above-described embodiment, an example of displaying a plane showing the piping system on the screen of the monitor 8 is shown, but a three-dimensional diagram of the piping system is displayed, and a mark K indicating that it is dangerous is generated here. It is also possible to notify the danger. Further, although the mark K on the monitor 8 shown in the above-described embodiment is displayed in a relatively narrow range, the mark K may be displayed in a wide range including a specific steam trap portion.

Further, in the above-described embodiment, danger notification such as display of mark K is provided as water hammer forecast processing, but the present invention is not limited to this, and maintenance of the relevant portion is strengthened based on, for example, water hammer occurrence prediction data. Maintenance processing such as water hammer can also be included.

Further, in the above-described embodiment, the sensors 32, 33, and 34 that directly measure the temperature and pressure are used, but instead of these, for inspection for inspecting malfunctions such as discharge failure and sealing failure of each steam trap. Sensors can also be used. This inspection sensor detects the temperature and vibration in the pipe at the installation location and outputs the temperature data and vibration data.

That is, when the steam trap has a discharge failure, the drain is excessively retained in the nearest pipe and the temperature drops. Therefore, if the detection temperature falls below a certain temperature, it is judged that the discharge failure has occurred. Can be done. Further, when the float of the steam trap has a poor sealing, a leaking sound is generated due to steam leakage. Therefore, if the detection vibration of a specific frequency is detected, it can be determined that the poor sealing has occurred.

Based on the data detected by the inspection sensor for inspecting the malfunction of the steam trap in this way, it is also possible to calculate the pressure in the pipe together with the temperature and determine whether or not the steam trap is saturated.

2: Drain 4: Flash steam 6: Control unit 7: Memory 10: Drain recovery pipe
11, 12, 13: Drain connection pipe 20: Steam transport pipe 32, 33, 34: Sensor
42, 43, 44: Steam trap P1, P2, P3: Water hammer occurrence predicted location

Claims (4)

Main piping that fluid moves inside,
A connection pipe connected to the main pipe, in which the fluid moves from upstream to downstream inside and flows into the main pipe.
An on-off valve, which is provided on the connecting pipe and blocks or opens the movement of fluid.
A detection unit provided on the connection pipe on the upstream side of the on-off valve, which detects the state in the connection pipe in the vicinity and outputs a state signal indicating the state.
Based on the received status signal, it is determined whether or not the fluid on the upstream side of the on-off valve is in a predetermined dangerous state, and when it is determined that the fluid is in a dangerous state, a predetermined specific value on the downstream side of the on-off valve is determined. Control unit that performs water hammer forecast processing for the location ,
A water hammer prediction system in the piping, which is characterized by being equipped with. Main piping where the drain moves inside,
A connection pipe connected to the main pipe, in which steam or drain moves from upstream to downstream inside and causes steam or drain to flow into the main pipe.
An on-off valve that is provided on the connecting pipe and shuts off or opens the movement of steam or drain.
A detection unit provided on the connection pipe on the upstream side of the on-off valve, which detects the state in the connection pipe in the vicinity and outputs a state signal indicating the state.
Based on the received status signal, it is determined whether or not the steam on the upstream side of the on-off valve is saturated, and when it is determined that the on-off valve is saturated , the predetermined specific location on the downstream side of the on-off valve is determined. control unit for water撃予paper processing,
A water hammer prediction system in the piping, which is characterized by being equipped with. In the water hammer prediction system in the pipe according to claim 1 or 2.
The detection unit is a water hammer prediction system in a pipe, which detects a state in the connecting pipe by detecting temperature and pressure. Main piping that fluid moves inside,
A connection pipe connected to the main pipe, in which the fluid moves from upstream to downstream inside and flows into the main pipe.
An on-off valve, which is provided on the connecting pipe and blocks or opens the movement of fluid.
In the water hammer prediction method regarding the water hammer prediction system in the pipe equipped with
Detects the condition inside the connecting pipe near the connecting pipe on the upstream side of the on-off valve.
Determine if the fluid on the upstream side of the on-off valve is in a predetermined danger state and determine
When it is determined that it is in a dangerous state, water hammer forecast processing is performed for a specific predetermined location on the downstream side of the on-off valve .
A method of predicting water hammer in piping, which is characterized by this.

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