JPS59560Y2 - Liquid supply device using pure fluid control element - Google Patents

Description

[Detailed description of the invention] This invention is a liquid supply device that incorporates a pure fluid control element in the circuit, and is an improved liquid supply device that prevents harmful fluids such as air from being sucked and mixed from the bypass output port of the element. Regarding the supply device.

I) For hot strip steel finishing rolling mills, improvements have been made to the cooling water supply device for the tube cooling device.

I will explain it step by step. Figure 1 shows the process of cooling the hot-rolled product 3 running on the table roll 1 by injecting water from the cooling water header 2. The water injection method is not limited to high pressure water injection using a spray nozzle, Low-pressure water injection using on-tube is also applicable.

The water supply system is composed of a pump source 4, piping 5, a shutoff valve 6, a piping 7, etc., and the shutoff valve 6 is opened to send water from the pump source 4 to the cooling water header 2.

Of course, there are also examples in which pressure regulating valves are installed in the middle of the pipes 5 and 7.

In this way, when the shutoff valve 6 is rapidly closed in the water supply system, surge pressure is generated inside the piping 5 on the upstream side of the shutoff valve 6.
It is known that this causes pressure fluctuations in cooling equipment in other locations and adversely affects cooling control.

It is also known that the flow velocity in the pipe 5 decreases, the pressure loss in the pipe decreases, and the primary pressure of the valve increases.

Therefore, in order to prevent the generation of this surge pressure and the rise in primary pressure, a water supply device as shown in Fig. 2 was developed (numerals 11 to 15 and 17 correspond to numerals 1 to 5゜7 in Fig. 1). ).

The main feature of this device is that the three-way switching valve 1 replaces the shutoff valve 6.
6 is installed and you do not want to send water to the cooling water header 12, switch the three-way switching valve 16 to the upper position and send the water sent from the pump source 14 through the pipe 18 to the appropriate water treatment. It is designed to be able to flow through a facility such as a scale sluice 19.

According to this device, it is possible to avoid the above-mentioned permanent setting, but the three-way switching valve 16 has many movable parts in contact with liquid, so maintenance requires a lot of time and manpower, and it takes a long time to switch the circuit and generates heat. There are problems such as difficulty in controlling the temperature of the rolled product.

The water supply device shown in FIG. 3 solves these problems with a configuration that is different from the conventional one.

(Symbols 21 to 25. 27 to 29 are 11 to 1 in Fig. 2.
5°17-19).

A major feature of this water supply device is that a pure fluid control element 26 (trade name: fluid valve) having no moving parts is used in place of the three-way switching valve 16.

That is, the pure fluid control element 26 is connected to one control port 31.
is connected to the air solenoid valve 30 through the other control port 33 and to the air solenoid valve 32 through the other control port 33, the input port 34 of the element is connected to the pump source 24 through the piping 25, and the output port 35 is connected to the piping 27. Cooling water header 22 via
, and the bypass output port 36 is connected to the scale sluice 29 via piping 28.

When the air solenoid valve 30 connected to the control port 31 is closed and the air solenoid valve 32 connected to the control port 33 is opened to open the control port 33 to the atmosphere, the ice sent to the input capo 1 and 34 is output. Out of the port 35, the cooling water is supplied to the header 22, and when the air solenoid valves 30 and 32 are opened and closed in reverse,
Water flows from input port 34 out bypass output port 36 and into scale sluice 29 .

It is a well-known fact that by incorporating the pure fluid control element 26 in this way, the switching speed of the circuit can be further increased and better control can be achieved.

However, on the other hand, the use of pure fluid control element 26 presents unique problems.

That is, the water sent to the input port 34 is transferred to the output port 3.
5 and is supplied to the cooling water header 22, negative pressure is generated in the bypass output port 36, air and water are sucked from the bypass output port 36, and the output port 3
5 side, causing trouble in cooling the hot-rolled product 23.

Negative pressure is generated at the bypass output port 36 when the ratio of the pressure at the input port 34 and the pressure at the output port 35 is smaller than a certain value determined by the pure fluid control element 26, that is, a value determined by the shape and dimensions of the element. It is.

To explain in more detail based on the drawings, Fig. 4 shows the relationship between the output port pressure, the input port pressure ratio, and the bypass output port pressure, and Fig. 5 shows the relationship between the output port water amount and the input port input. This shows the relationship between the water volume ratio and the output port pressure to input port pressure ratio.
D corresponds to FIG.

Comparing both figures, point A in Figure 5 indicates the point where the ratio of the output port pressure to the input port pressure is 0, the water output from the output port is equal to the water input from the input port, and the pressure at the bypass output port at this time is is -2.3 mAq from point A in Fig. 4.

In addition, point 8 is the maximum point of the ratio of the pressure at the output port to the pressure at the input port, at which the amount of water flowing out of the output port is equal to the amount of water entering the input port, that is, the limit pressure ratio (maximum pressure recovery rate).
The pressure at the bypass output port at that point is;
In FIG. 4, it is OmAq.

Furthermore, from point 0 to point D, the incoming water from the input port does not flow to the output port, but the entire amount flows to the bypass output port.

Therefore, the pressure at the bypass output port is equal to the resistance of the attached piping equipment.

From the above, it is clear that in a water supply system using a pure fluid control element, if the output port pressure is used at a pressure below the maximum pressure recovery rate, negative pressure problems will occur.

The purpose of this invention is to prevent harmful fluids such as air from being sucked and mixed from a bypass output port in a liquid supply device using a pure fluid control element.

The liquid supply device of this invention is characterized in that the outlet side piping of the output port of the pure fluid control element and the outlet side piping of the bypass output port are connected by a connecting pipe, and a flow rate adjustment device is attached to this connecting pipe. .

That is, to explain the embodiment shown in FIG. 6, in a circuit incorporating the pure fluid control element 126, the output port 1
Connecting the outlet side piping 127 of No. 35 and the outlet side piping 128 of the bypass output port 136 with a connecting pipe 137,
A variable or fixed flow rate adjustment device 13 is connected to this communication pipe 137.
Install 8.

In that case, the numbers 121 to 136 are replaced by the numbers 21 to 3 in FIG.
6, the end of the bypass output port 136 outlet side piping 12B is immersed in water in the scale pit 129, and the vertical relative distance between the water surface 139 and the bypass output port 136 is maintained at 1 m or more and 11 m or less. It is preferable to do so.

In the above configuration, the flow rate of water flowing through the pure fluid control element 126 is determined by the inlet pressure of the input port 134 and the size of the pure fluid control element 126.

Now, if water flows from the manual port 134 to the output port 135, the pressure at the output port 135 and the input port 134
When the pressure ratio becomes less than the maximum pressure recovery rate, negative pressure is generated at the bypass output port 136.

At this time, the flow rate adjustment device 13B provided in the connecting pipe 137
When opened, the high pressure water on the output port 135 side flows to the negative pressure side of the bypass output port 136.

That is, the flow rate adjustment device 138 is adjusted and the output port 1-1 is adjusted.
By feeding water from the 35 side, the negative pressure on the bypass output port 136 side can be reduced to zero or alleviated.

In this way, from the pure fluid control element 126 to the output port 13
5 passes through the flow regulator 13B again and circulates, so according to this embodiment, the bypass output port 13
The phenomenon in which fluid (water, air, etc.) from the scale pit 129 is sucked from the scale pit 129 can be prevented.

Note that this invention is not limited to the above embodiment without departing from the gist, and the fluid is not limited to cooling water.

As explained above, this device connects the outlet side piping of the output port of the pure fluid control element and the output side piping of the bypass output port with a connecting pipe, and also attaches a flow rate adjustment device to this connecting pipe, so that the bypass output It is possible to prevent the suction and mixing of harmful fluids such as air from the port, and it is possible to supply cooling water that is ideal for the cooling process of hot-rolled products, etc.

[Brief explanation of the drawing]

FIGS. 1 to 3 are flowcharts showing a conventional cooling water supply device applied to a cooling process for hot-rolled products. 4 and 5 are diagrams illustrating the cause of negative pressure generated at the bypass output port in the circuit incorporating the pure fluid control element shown in FIG. 3. FIG. FIG. 6 is a flowchart showing a cooling water supply system according to an embodiment of this invention. 1, 11.21.121... table roll, 2.1
2.22゜122...Cooling water header, 3.23.12
3...Hot-rolled product, 4゜14, 24.124...Pump source, 6...Shutoff valve, 16...Three-way switching valve, 19.
... Scale sluice, 26.126 ... Pure fluid control element, 30.32.130.132 ... Air solenoid valve,
31.33°131, 133... control port, 34,
134...Input port, 35°135...Output port, 36.136...Bypass output port, 137.
...Communication pipe, 138...Flow rate adjustment device.

Claims (1)

[Scope of utility model registration request] In a liquid supply device that incorporates a pure fluid control element in the circuit, when connecting the outlet side piping of the output port of the element and the outlet side piping of the bypass output port with a connecting pipe, it is necessary to attach a flow rate adjustment device to this connecting pipe. A liquid supply device using a pure fluid control element characterized by: