JP2564532B2 - Mother tube drain elimination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is suitable for effectively discharging the drain of steam or gas pipes that generate drain due to changes in temperature, and does not damage the pipe. To provide such a device.

<Prior Art> Pipes for steam and gas are widely used in various industrial fields, and various types of pipe lines and heat insulating shapes are provided. In the case of steam having a temperature higher than the atmospheric temperature, a drain is generated when it is cooled, and therefore a drain trap has been often used to discharge the drain. Although various means such as a bucket type and a shock type are adopted as the drain trap, all of them utilize the difference in specific gravity between the generated drain and steam or gas, and the temperature difference. In some cases, a drain valve may be provided and the drain valve may be opened for a short time to discharge the drain if necessary.

<Problems to be Solved by the Invention> When the drain trap installed in the steam piping system operates, steam is discharged together with the drain. It is desired to minimize the amount of steam discharged together with the drain, although there is a difference depending on the type of the drain trap and the operating pressure. In addition, since the drain valve is used in the high-pressure system of the boiler without providing a drain trap, the drain accumulated in the drain pipe flashes due to fluctuations in the steam pressure and the thermal shock on the steam mother tube side pipe material. Is a cause of cracking in the piping.

It is necessary to minimize the amount of flushing due to the change in the pressure of the steam mother pipe and to minimize the discharge of steam during the operation of the trap, which is a problem to be solved by the present invention.

<Means for Solving Problems> The above problems can be solved by selecting a form of heat retention and providing a resistor tube or a decompression orifice on the upstream side of the drain trap or the drain valve.

<Object of the Invention> An object of the present invention is to propose a structure of an apparatus which eliminates unnecessary discharge of steam and does not damage the steam pipe due to flushing.

<Example 1> FIG. 1 is a piping structure diagram showing a first example of the present invention. The steam mother pipe 1 is provided with a Z-shaped drain pipe 2 (Z-shaped pipe) having a portion that hangs downward. It is connected to the drain trap inlet valve 3, the register tube 4, the drain trap 5, and the drain trap outlet valve 6. Further, the pipe is branched in the horizontal direction immediately before the drain trap inlet valve 3 to serve as a pipe system for coping with a malfunction of the drain trap, which is a bypass valve 7 of the drain trap 5, and a drain trap 5 from which the drain trap 5 is suspended.
The bypass pipe 8 is provided to join the drain outlet pipe 10 to discharge a part of the drain and steam. Further, as shown in the figure, the heat insulating material 9 is used to keep the heat in the upstream piping up to the drain trap inlet valve 3 and the outlet of the bypass valve 7 of the drain trap 5.

Since the resistor tube 4 and the subsequent parts are cooled, even if the pressure of the steam mother tube 1 is reduced, it does not easily flush. The flash when the pressure drops drastically is also mitigated by the register tube 4. Further, the upstream side of the register tube 4 is kept warm, and it is also effective to arrange it vertically so that the drain does not collect.

Further, the Z-shaped pipe 2 is composed of a pipe 2a hanging down from the mother pipe as shown in the drawing, a horizontal pipe 2b, and a hanging pipe 2c. By bending in this way, the mother pipe is also subjected to thermal shock due to jetting water droplets (splash) due to flushing. There is no effect.

<Embodiment 2> FIG. 2 shows a piping structure diagram of a second embodiment of the present invention.

An electric valve of the drain valve 11 is provided from the drain pipe 2 through the register tube 4 and the bypass valve 7 is provided by horizontally branching the pipe immediately before the register tube 4, and the bypass pipe 8 from the outlet pipe is the drain outlet pipe. It merges with 10 and is discharged.

A temperature detector 12 is provided on the upstream side of the drain valve 11, and when the inlet fluid temperature of the drain valve 11 is detected to be lower than the saturation temperature corresponding to the pressure in the steam mother pipe 1 by a specified value, the signal is output. It is placed in the control box 13, and the drain valve 11 is opened for a certain period of time by the command and then fully closed.

After that, the temperature of the fluid at the inlet of the drain valve 11 once rises to near the saturation temperature of the steam mother pipe, then falls again, and the circuit is used so as to repeat the above operation. Such means can be applied to a piping system in which a drain trap cannot be used.

<Operation> The same pressure as the above-mentioned mother pipe is applied to the drain trap until the drain trap operates, and due to the steam flow generated at the same time when the drain trap opens, a pressure loss occurs before and after the resistor tube or the decompression orifice.
Since the pressure immediately before the drain trap is lowered, the saturation temperature is also lowered, and the high temperature portion of the accumulated drain is flushed. For this reason, drainage is discharged, but the amount of excess steam discharged can be made very small.

The same applies when a drain valve is used. Regarding the speed at which the steam mother pipe pressure drops rapidly and the accumulated drain flashes, the drain between the register tube and the drain trap flashes and flows in the reverse direction through the register tube, resulting in pressure loss. The speed becomes slower, and the steam mother tube is not rapidly cooled, which causes cracking.

<Effects of the Invention> By implementing the present invention, the amount of steam discharged during the operation of the drain trap becomes small, and the effect of preventing heat loss is large in a large plant from the viewpoint of energy saving. Further, even if the pressure of the steam mother pipe is rapidly decreased, the heat-retaining range is limited, and the thin register tube is supercooled, so the amount of drain flushing is small, and the water droplets can be removed by the Z-shaped pipe shape. Due to the effect, cracking due to thermal shock of the steam mother tube does not occur. For the resistor tube, it is sufficient to select the length of the pipe with a small diameter and connect it with a dimension that will produce the necessary pressure loss, and a large energy saving effect can be obtained with economical equipment.

[Brief description of drawings]

FIG. 1 is a piping structure diagram showing the first embodiment of the present invention, and FIG.
The drawing is a piping structure diagram showing a second embodiment of the present invention. 1 …… Mother pipe, 2 …… Z-shaped pipe 3 …… Drain trap inlet valve 4 …… Register tube 5 …… Drain trap 6 …… Drain trap outlet valve 7 …… Bypass valve, 8 …… Bypass piping 9 …… Heat insulation material 10 …… Drain outlet pipe 11 …… Drain valve, 12 …… Temperature detector

Claims (4)

(57) [Claims] 1. A Z-shaped pipe comprising a hanging pipe that hangs from the lower surface of the mother pipe and a pipe that extends horizontally from the lower end of the pipe and that further hangs down. A bypass valve is provided in a pipe line extending horizontally from the lower portion of the Z-shaped pipe, a resistance member for imparting resistance to the drain flow is connected to the lower end of the Z-shaped pipe, and a drain valve is connected to this resistance member to connect the Z-shaped pipe to the Z-shaped pipe. A mother pipe drain elimination device characterized by keeping the bypass valve warm. 2. The mother pipe drain eliminating device according to claim 1, wherein the resistance member is a drain trap inlet valve and a register tube, and a drain trap and a drain trap outlet valve are provided in place of the drain valve. . 3. The mother tube drain eliminating device according to claim 1, wherein the resistance member is a resistor tube with a temperature detector. 4. The mother pipe drain elimination device according to claim 3, further comprising a control box for opening the drain valve by using the outlet temperature of the register tube as a signal.