JPS62269210A - Protecting method for volume type flowmeter - Google Patents

Abstract

PURPOSE:To prevent a replenishing water flow rate from flowing exceeding a planned value flow rate, by controlling the replenishing water which passes through a volume type flowmeter, by a replenishing water flow rate regulating valve small valve. CONSTITUTION:A flow rate controller 8 and a low level priority device 9 are installed to a volume type flowmeter 6 in order to control a flow rate of replenishing water so as to be constant, to the volume type flowmeter 6, even when the replenishing water exceeding a planned value flow rate flows, by following a variation of pressure of an inlet of the volume type flowmeter 6 at the upstream side of a replenishing water flow rate regulating valve small valve 5 at the time of operation of a replenishing water pump 3. In this way, when the replenishing water passing through the volume type flowmeter 6 has reached the planned value flow rate, an opening of the replenishing water flow rate regulating valve small valve 5 is adjusted automatically by a control signal sent from the flow rate controller 8 to the low level priority device 9, so that the replenishing water becomes below the planned value flow rate.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a make-up water system in which two large and small make-up water flow rate regulating valves and a volumetric flowmeter are provided in the small-capacity make-up water regulating valve system, and in particular, The present invention relates to an excessive flow rate of a volumetric flowmeter and a method for preventing scale overflow and damage to the flow meter due to the excessive flow rate.

[Conventional technology]

An example of a condenser makeup water system equipped with a volumetric flowmeter 6 on the upstream side of the makeup water flow rate adjustment valve small valve 4, makeup water flow rate adjustment valve small valve 5, and makeup water flow rate adjustment valve small valve 5 shown in FIG. shows.

During normal operation, the bypass system a of the make-up water pump 3 is connected to the make-up water tank 2 (during normal operation, the make-up water pump 3 is stopped), and the volumetric flow meter 6. Makeup water flow rate adjustment valve small valve 5
Makeup water is supplied to the condenser 1 through the condenser 1. Further, the capacity of the make-up water flow rate adjustment valve small valve 5 is determined based on the amount constantly required when the make-up water pump 3 is in a stopped state (due to cycle loss, etc.).

However, a large amount of make-up water is required during startup and water filling, and in this case, the make-up water pump 3 is operated and the make-up water flow rate adjustment valve 4 is activated by the control signal from the condenser water level controller 7.
is adjusted, and a large amount of makeup water is supplied to the condenser 1.

At this time, the pressure on the upstream side of the make-up water flow rate adjustment valve small valve 5 changes, and the volumetric flowmeter 6 installed on the upstream side of the make-up water flow rate adjustment valve small valve 5 detects that the make-up water exceeds the planned flow rate. There was a drawback that the volumetric flowmeter 6 was damaged.

Although the condenser make-up water system has been described above, the shaft chilled water make-up water system has similar problems.

[Problem that the invention seeks to solve]

In the conventional technology, when a large amount of make-up water is required such as during start-up and water filling, the make-up water pump is turned over, and no consideration is given to the amount of make-up water being sent and changes in the inlet pressure of the volumetric flowmeter. First, due to changes in the inlet pressure of the volumetric flowmeter, make-up water flows at a flow rate higher than the planned flow rate, causing the volumetric flowmeter to exceed its scale and be damaged.

An object of the present invention is to install a flow rate blood pressure meter and a low priority device in a volumetric flowmeter, and to input a control signal of the flow rate blood meter to the low priority device, thereby adjusting a make-up water flow rate adjustment valve small valve. The purpose of this invention is to prevent an excessive flow rate of make-up water passing through a volumetric flowmeter and damage to the volumetric flowmeter due to the excessive flow rate.

[Means for solving problems]

The purpose of the above is to operate the make-up water pump to supply make-up water to the condenser when a large amount of make-up water is required for startup, water filling, etc. The pressure on the upstream side of the installed volumetric flowmeter changes, causing makeup water to flow at a rate higher than the planned flow rate.

Due to excessive flow of make-up water passing through the volumetric flow meter,
The volumetric flowmeter is damaged.

Therefore, as a means to prevent the above, a flow rate blood pressure meter and a low priority device are installed in the volumetric flowmeter, and 1) the control signal of the flow rate blood meter described in ji is inputted to the low priority device to adjust the makeup water flow rate. This is achieved by controlling the small valve at a constant flow rate.

[Effect]

To control the constant flow rate of the make-up water flow rate adjustment valve, a volumetric flow meter is equipped with a flow rate blood pressure meter and a low-level priority device, and when the makeup water flow rate reaches a certain planned flow rate, the low-level priority device is set from the flow rate blood pressure meter. act to send control signals to the device.

As a result, the make-up water passing through the volumetric flowmeter is regulated by the make-up water flow rate adjustment valve small valve, so that the make-up water flow rate never exceeds the planned flow rate.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

In Fig. 1, make-up water during normal operation is supplied from the make-up water tank 2 to the bypass system of the make-up water pump 3 (during normal operation,
The makeup water pump has stopped. ), volumetric flow meter 6, makeup water flow rate adjustment valve small valve 5 (during normal operation, the valve opening degree is automatically adjusted by the control signal of the condenser water level adjustment meter 7).

), and is supplied to the condenser 1 through the following.

The capacity of the make-up water flow rate adjustment valve small valve 5 is determined by the amount always required when the make-up water pump 3 is stopped (due to cycle loss, etc.).

Also, as explained in Fig. 3, during normal operation at the design point A, makeup water is supplied without operating the makeup water pump 3 using the differential pressure between the still water tank 2 and the condenser internal pressure. can do.

When a large amount of make-up water is required for startup, water filling, etc., the make-up water pump 3 is operated.

At this time, the opening degree of the make-up water flow rate adjustment valve 4 is automatically adjusted by the control signal from the condenser water level controller 7, and a large amount of make-up water is sent to the condenser 1.

However, when the make-up water pump 3 is in operation, the inlet pressure of the make-up water flow rate adjustment valve small valve 5 changes, and make-up water flows into the volumetric flowmeter 6 at a flow rate higher than the planned flow rate.

It was also found that the volumetric flowmeter 6 was damaged due to an excessive flow rate of makeup water passing through the volumetric flowmeter 6. (
(Excessive flow rate area from point A to point B) Therefore, to explain with reference to FIG. , even when makeup water flows in excess of the planned flow rate.

In order to control the flow rate of make-up water to the volumetric flowmeter 6 at a constant level, by installing a flow control meter 8 and a low priority device 9 in the 1-volume flowmeter 6, the makeup water passing through the volumetric flowmeter 6 can be planned. When the value flow rate is reached, the valve opening of the make-up water flow rate adjustment valve small valve 5 is automatically adjusted by the control signal from the flow rate blood control meter 8 to the low priority device 9 to bring the make-up water within the planned value flow rate. 6 (from point 0 to point D in Fig. 4) By controlling the make-up water flow rate flowing through the single volume type flow meter 6 to a constant flow rate using the flow rate blood pressure meter 8 and the low priority device 9, the volume type It becomes possible to prevent the volumetric flowmeter 6 from being damaged due to an excessive flow rate of makeup water passing through the flowmeter 6 and an excessive dε of the makeup water.

〔Effect of the invention〕

According to the present invention, it is possible to prevent accidents by adding a simple control device without increasing the capacity of the volumetric flowmeter to exceed the specified value for makeup water, and due to the small scale, measurement accuracy during normal operation can be improved. Improved and safe Plan I-operation is possible.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the configuration of a conventional make-up water system, Fig. 2 is a diagram showing an example of the configuration of the make-up water system according to the present invention, and Fig. 3 is a characteristic curve diagram of a conventional make-up water flow rate adjustment valve small valve. , FIG. 4 is a characteristic curve diagram of the make-up water flow rate regulating valve small valve according to the present invention.

Claims (1)

[Claims] 1. A make-up water system of a thermal power plant having two or more types of make-up water supply sources or supply lines with different supply pressures, and two large and small make-up water flow rate adjustment valves for adjusting the make-up water flow rate. , and in a system where a volumetric flowmeter is installed in a small-capacity make-up water regulating valve system, if a condition is established in which the makeup water flow rate passing through the volumetric flowmeter exceeds a specified value, other control signals are normally Therefore, a volumetric flow meter is installed in the make-up water flow rate adjustment valve that controls the make-up water flow rate, and a low priority device is installed in the above control signal line to control the flow rate from the above flow rate regulator. A method for protecting a volumetric flowmeter, comprising inputting a signal and adjusting a make-up water flow rate adjustment valve. 2. In claim 1, if a condition is established in which the flow rate of make-up water passing through the volumetric flowmeter exceeds a specified value, the make-up water flow rate is normally controlled by another control signal. A flow rate regulator is installed in the volumetric flowmeter in the water flow rate regulating valve, and the make-up water flow rate regulating valve is adjusted based on the control signal from the flow rate regulator, so that the make-up water flow rate passing through the volumetric flowmeter is below a specified value. A method for protecting a volumetric flowmeter, which is characterized by preventing an excessive flow rate of make-up water passing through the volumetric flowmeter and protecting itself by controlling the volumetric flowmeter.