JPH0225607A - Vapor desuperheating valve - Google Patents

Abstract

PURPOSE:To enable an efficient decrease of temperature of over-heated vapor to be performed with a simple device by a method wherein a valve opened by varying a degree of opening in response to a flow rate of vapor is arranged within a valve casing and a spray valve fixed to this valve body may open or close a spray valve port in response to a displacement of the valve body. CONSTITUTION:When a spray valve por 36 is completely closed and a slight clearance 44 is opened between a valve body 18 and an inner wall of a cylinder 12, over-heated vapor fluid may flow, resulting in that a valve body 18 is displaced toward an outlet port against a spring 17 under its flow rate resistance, the fluid may flow from the opened valve and the inner wall surface of the cylinder 12 to an outlet port 10. The spray valve port 36 may also be opened in response to a displacement of the valve body at this time and the sprayed water is stomized and its temperature is decreased. As an amount of vapor is further increased, the valve 18 is further displaced to an outlet side under its flow rate resistance. Simultaneously, a passing area between the inner wall surfaces of the cylinder is also increased and its flow rate resistance is reduced, so that the valve is stopped at a point where the flow rate resistance is balanced with the biasing spring. That is, a displacement of the valve body is determined in response to a vapor flow rate and then a degree of opening of the spray valve port is also determined and an amount of sprayed water is also determined.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a steam temperature reduction valve used for reducing the temperature of superheated steam.

Generally, steam is generated as relatively high-pressure steam in a steam generation source such as a boiler, and is used after being reduced in pressure at the inlet side of various steam-using equipment depending on the purpose of use of the steam-using equipment. Due to its nature, high-pressure steam becomes superheated steam when its pressure is reduced, making it difficult to adjust the amount of heat transferred in steam-using equipment, and making uniform heat transfer impossible.

<Prior Art> Generally, the temperature of superheated steam is reduced by this type of temperature reduction device by injecting cooling water into the flow of superheated steam and absorbing the thermal energy of the superheated steam by the latent heat of the cooling water.

Therefore, conventionally, as shown in FIG. 2, pressurized spray water is passed through a spray water pipe 50 to a spray nozzle 52.
A device was used that sprayed directly onto superheated steam to cool it down to a predetermined temperature. This is done by arranging the spray nozzle 52 on the upstream side in the superheated steam passage 54 and providing a temperature detector 56 on the downstream side, so that the superheated steam reaches a predetermined temperature in response to the temperature detected by the temperature detector 56. to adjust the opening degree of the control valve 58. In other words, the deviation between the set value of the steam temperature and the detected temperature is calculated, the amount of spray from the spray nozzle 52 is determined by the PID controller so as to reduce this difference to zero, the control valve 5B is operated, and the steam temperature is It controls the

Problems to be Solved by the Present Invention> The above device includes a temperature detector that detects the reduced temperature of steam, a control valve that adjusts the opening degree according to the detected temperature, and the temperature sensor and the control valve. In addition, the temperature sensor must be installed separately in the steam passage, and the control valve must be installed in the spray water passage, respectively, which raises the problem of increased equipment and construction costs. In addition, the control becomes complicated, and determining the PID constant is difficult and requires experience.

The technical problem of the present invention is to reduce the temperature of superheated steam efficiently with a simple and inexpensive device without requiring complicated control.

Means for Solving the Problems> The technical means of the present invention taken to solve the above technical problems is to provide a spray valve port for spraying water in a valve casing having an inlet and an outlet. , a valve body that forms a conical cylindrical part that temporarily expands toward the outlet side, is always biased toward the inlet side by a biasing spring inside the cylindrical part, and closes the valve by changing its opening degree according to the flow rate of steam flowing inside the valve casing. Place the
A spray valve element is attached to this valve element, and the spray valve element opens and closes a spray valve port in accordance with the displacement of the valve element.

Function> When steam is not passing through the valve casing, the valve element maintains the closed state at the small diameter part of the conical cylinder part by the biasing spring. At this time, the spray valve body provided integrally with the valve body also closes the spray valve port, thereby stopping the ingress of spray water.

When the steam fluid flows, the fluid moves the valve element toward the outlet side against the biasing force of the biasing spring. When the valve body moves, the spray valve body also closes the spray valve port, spray water is sprayed inside the casing, and the temperature of the superheated steam is reduced. As the amount of steam passing through increases, the flow resistance increases and the valve body moves toward the outlet side, but at the same time, the distance between the inner wall of the conical cylinder and the valve body increases, and the opening area also increases, which increases the flow resistance. becomes smaller and the valve body stops at a position balanced with the biasing spring. Therefore, the opening degree of the valve is determined according to the amount of steam passing through, and the opening degree (displacement) of the spray valve port is also determined accordingly.

Strictly speaking, the specific heat differs depending on the pressure of the steam, so even if the steam flow rate is the same, the amount of water sprayed must also be changed, but in reality, the specific heat can be considered to be almost the same depending on external conditions such as heat radiation, so The amount can be adjusted depending on the amount of steam passing through regardless of the pressure.

Unique effects〉 The present invention produces the following unique effects.

Since the amount of spray water can be automatically adjusted using a mechanical configuration, there is no need for expensive pressure detectors, control valves, or connecting wires that connect the two, and the steam temperature can be reduced at low cost with a simplified device. be able to. Furthermore, the set temperature of the passing steam can be adjusted by adjusting the adjustment rod.

<Example> An example showing a specific example of the above technical means will be described (see FIG. 1).

The parts 2, 4.6 form a valve casing with an inlet 8 and an outlet 10. The member 4 forms a conical cylindrical portion 12 which widens slightly in the direction of the outlet. The first A receiver 14 is a fluid through hole 16
is provided, forming a bearing 19 in the center, and connecting member 2 and member 4.
Secure it in between.

A valve body 18 having a diameter large enough to substantially close the small diameter portion of the conical cylindrical portion 12 is disposed within the conical cylindrical member 12 so as to be biased toward the inlet side by a biasing spring 17. is bearing 1
A bimetal 22 in the form of a disk that expands at high temperature is provided on the exit side of the bimetal 9 and is locked with a snap ring 24.

A second bearing 26 is provided between the member 4 and the member 6, and the valve seat support member 2
Fix 8 with pincers/υ. An end of a spray pipe 30 introduced into the member 6 from the outside is connected to the valve seat support member 28, and a valve seat 38 having a spray valve port 36 on the outlet side is attached.

On the other hand, a spray valve body 32 is attached to the inlet side of the valve body 18,
The spray valve port 36 is opened, and the valve shaft 34 is guided by the second bearing 26. The second bearing 26 and the valve seat support member 28 are also provided with fluid passage holes 40 and 42, respectively.

The action is as follows. FIG. 1 shows a state in which the spray valve port is completely closed, and at this time there is a slight gap 44 between the valve body 18 and the inner wall of the cylindrical portion 12. This is a measure to prevent the valve body 18 from initially becoming difficult to open against the biasing spring 17 when the flow rate is small.

When the superheated steam fluid flows, the flow resistance causes the valve body 18 to be displaced toward the outlet side against the spring 17, and the fluid flows from the opened valve body and the inner wall surface of the cylindrical portion 12 to the outlet 10, and the valve body at this time The spray valve port 36 also opens in accordance with the displacement of the water, and the water is sprayed to reduce the temperature.

When the amount of steam increases further, the flow resistance causes the valve body 18 to be further displaced toward the outlet side, but at the same time, the passage area between the inner wall surfaces of the cylindrical portion also increases and the flow resistance becomes smaller, so that the flow resistance is reduced by the biasing spring. The valve body stops at the point where it is balanced. That is, the displacement of the valve body is determined according to the steam flow rate, the opening degree of the spray valve port is also determined, and the amount of spray water is also determined accordingly.

Normally, when the spray valve port 36 is closed, the steam that has passed through the gap 44 between the valve body 18 and the inner wall of the cylindrical part 12 has almost no effect on the secondary side due to heat radiation, but if some cause If too much steam flows and the secondary temperature rises too much,
The bimetal 22 relaxes and pulls the valve shaft 20 to open the spray valve 36 and reduce the temperature. That is, this bimetal only operates in abnormal situations.

As mentioned above, the specific heat varies depending on the pressure of the steam, but
When handling it in a process, it can be assumed that the specific heats are almost the same.
Therefore, if the degree of heating (temperature increase from saturation temperature) is the same at all pressures, a common spray valve diameter may be used, but if the degree of heating is different, it is better to change the valve diameter by replacing the valve seat 38. good.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a steam attemperation valve according to the present invention, and FIG. 2 is a conventional steam attemperation device. 8 2 Ports 12: Conical cylindrical part 22: Bimetal 36: Spray valve port 10: Outlet 18: Valve body 32 Nispre 1 Valve body name 10

Claims (1)

[Claims] 1. A spray valve port for spraying water and a conical cylindrical part that temporarily expands toward the outlet side are formed in the valve casing that has an inlet and an outlet, and a biasing spring inside the cylindrical part is always attached to the inlet side. A valve element is arranged to open the valve by changing the degree of opening according to the flow rate of steam flowing inside the valve casing, and a spray valve element is attached to this valve element, and this spray valve element changes its opening degree according to the displacement of the valve element. A steam detemperature valve that opens and closes the spray valve port.