JP2008160949A - Drainage system for cable duct - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely pump up water by effectively removing a dead air space generated on an inlet side of a check valve or back pressure applied to the outlet side of the check valve. <P>SOLUTION: This drainage system has a pump 5 which generates pressure for pushing up water W onto the ground, being installed inside a cable duct 2, a pumping pipe 6 which guides the water W pushed up by the pump 5, being connected to the discharge port of the pump 5, a check valve 7 which allows only the water current flowing toward the ground from within the cable duct 2, being installed midway in the pumping pipe 6, an air vent pipe 10 whose one end is connected to the inlet side of the check valve 7 in the pumping pipe 6 and the other end is opened, an air vent valve 11 which changes the area of the passage of the air vent pipe 10, being installed midway in the air vent valve 10, a drain pipe 12 whose one end is connected to the outlet side of the check valve 7 and the other end is open, and a drain pipe 13 which changes the area of the passage of the drain pipe 12, being installed midway in the drain pipe 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cable duct that stores electrical equipment such as a cable in a power plant or the like and is buried in the ground, and more particularly to a system for lifting and discharging water accumulated in the cable duct.

  Conventionally, in power plants, etc., cable ducts (also called hand holes) have been used to embed equipment such as power cables in the ground, and various technologies related to these cable ducts have been developed. Yes. For example, as for the construction method, the main body or U-shaped main body composed of the opposing wall and underground wall is made of precast, and the inner wall provided in the interior is a building block of a size and weight that can be enforced manually What is configured is disclosed (see Patent Document 1).

  Such cable ducts tend to collect rainwater due to their features such as shape and installation position. In order to maintain the equipment stored in the cable duct, the accumulated water must be collected at least before reaching the storage facility. It has a problem that it must be discharged.

For this reason, the cable duct is often provided with a drainage system for lifting and discharging the water accumulated inside the cable duct. FIG. 3 shows an example of a drainage system 101 of a conventional cable duct 100. The drainage system 101 includes a pump 110, a pumping pipe 111, a check valve 112, and a side groove 113. According to the drainage system 101, when the water level detection device 115 installed on the inner wall of the cable duct 100 detects that the water W accumulated in the cable duct 110 has reached a predetermined water level, the pump 110 is activated. Thus, the water W passes through the pumping pipe 111 and the check valve 112 and is discharged to the ground side groove 113. As is well known, the check valve 112 is opened by the upward water pressure generated by the action of the pump 110, and is not opened by the pressure (back pressure) of water located above the check valve 112. Only the water flow toward is allowed.
JP-A-9-273139

  However, in the conventional drainage system 101 shown in FIG. 3, it is difficult for the pressure increase by the pump 110 to be transmitted to the check valve 112 due to the air reservoir 120 generated at the inlet portion of the check valve 112, or when the side groove 113 is full. In other cases, the back pressure due to the drainage reservoir 121 located above the check valve 112 increases, so that the check valve 112 may not be opened and the water W in the cable duct 100 may not be discharged. In particular, the stoppage of the drainage function caused by the air reservoir 120 is fatal.

  In view of this, the present invention effectively removes the air accumulated on the inlet side of the check valve and the back pressure to the check valve that is generated when the side groove is full. The purpose of this is to ensure that it can be discharged to the outside.

  The present invention for solving the above problems is a system for discharging water accumulated in a cable duct installed in the ground to the ground, and is installed in the cable duct to allow the water to flow to the ground. A pump for generating a pressure to be pushed up, a pumping pipe connected to the discharge port of the pump and guiding the water pushed up by the pump to the ground, installed in the middle of the pumping pipe, in a direction toward the ground from the inside of the cable duct A check valve that allows only water flow, one end connected to the inlet side of the check valve of the pumping pipe, the other end being opened, an air vent pipe installed in the middle of the air vent pipe, An air vent valve for changing the passage area is provided (claim 1).

  According to this configuration, since the air pool on the check valve inlet side can be removed by the action of the air vent pipe and the air vent valve, the pumping pressure by the pump is sufficiently non-returned without causing the cushion action due to the air pool. It will be transmitted to the valve inlet. Thereby, it is possible to prevent a problem that water cannot be pumped even though the pump is operating.

  Further, in the configuration according to claim 1, further, one end is connected to the outlet side of the check valve of the pumping pipe, and the other end is opened, and the drainage pipe is installed in the middle of the drainage pipe. It is preferable that a drain valve for changing the passage area of the drain pipe is provided.

  According to this configuration, the water existing on the check valve outlet side can be discharged to the outside of the pumping pipe by the action of the drain pipe and the drain valve, so the back pressure applied to the check valve (from the check valve) (Pressure due to water existing on the downstream side) can be reduced. Thereby, it is possible to prevent a problem that water cannot be pumped even though the pump is operating.

  Further, in the configuration according to claim 1 or 2, the air vent valve is preferably configured or operated so as not to be fully closed (claim 3).

  Thereby, generation | occurrence | production of the air pocket itself can be suppressed.

  Further, in the configuration according to any one of claims 1 to 3, based on the detection result by the air pool detection means for detecting the occurrence of air pool on the inlet side of the check valve and the air pool detection means. And an air vent valve control means for controlling the opening degree of the air vent valve (Claim 4). Further, in the configuration according to any one of Claims 1 to 4, the check valve A back pressure detecting means for detecting the water pressure applied to the outlet side, and a drain valve control means for controlling the opening degree of the drain valve based on a detection result by the back pressure detecting means may be provided. 5).

  Thereby, maintenance and operation of the system can be automated.

  As described above, according to the present invention, the air reservoir on the inlet side of the check valve can be removed by the air vent pipe and the air vent valve. Further, the back pressure on the outlet side of the check valve can be removed by the drain pipe and the drain valve. Furthermore, the occurrence of air pockets can be suppressed by configuring or operating the air vent valve so as not to be fully closed (always open slightly). Furthermore, a means for detecting the occurrence of air accumulation and controlling the air vent valve based on the detection result or a means for detecting the back pressure to the check valve and controlling the water drain valve based on the detection result is provided. Thus, the maintenance and operation of the system can be automated.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a drainage system 1 according to a first embodiment for lifting and discharging water W accumulated in a cable duct 2 to a side groove 15 formed on the ground surface. The cable duct 2 is a known one provided in the ground for embedding a power cable or the like.

  The drainage system 1 according to this embodiment includes a pump 5, a pumping pipe 6, a check valve 7, an air vent pipe 10, an air vent valve 11, a water drain pipe 12, a water drain valve 13, and a side groove 15. .

  The pump 5 is a well-known one configured with an electric screw or the like, and generates a force that pushes up the water W accumulated at the bottom of the cable duct 2 to the ground surface. The pump 5 is driven when the water level detection device 16 installed on the inner wall of the cable duct 2 detects that the water W in the cable duct 2 has reached a predetermined water level.

  One end of the pumping pipe 6 is connected to the discharge port 17 of the pump 5, and the other end opens toward the side groove 15, and the pump 5 and the side groove 15 are communicated with each other.

  The check valve 7 is installed in the middle of the pumping pipe 6 and is opened by the water pressure from below by the pump 5 and is closed by the water pressure from above by the weight of water on the side groove 15 side. This allows the water flow from the upper side to the upper side and the water flow from the upper side to the lower side to be inhibited.

  One end of the air vent pipe 10 is connected to the inlet (downward) side of the check valve 7 of the pumping pipe 6, and the other end opens to the inside of the cable duct 2. The function of removing the air reservoir 21 is provided.

  The air vent valve 11 is installed in the middle of the air vent pipe 10 and adjusts the air removing action of the air vent pipe 10. The air vent valve 11 in this embodiment can be adjusted in its opening degree manually (including mechanically operated by a handle or the like, and remotely operated by a predetermined electronic means), and is always in a slightly open state. That is, it is configured or operated so as not to be completely closed. According to this configuration, when pumping by the pump 5 is not performed satisfactorily, the worker increases the opening degree of the air vent valve 11 so that the air reservoir 21 at the inlet of the check valve 7 is quickly removed, and the pump 5 The pressure due to the water is reliably transmitted to the check valve 7, so that the pumping capacity is restored. Moreover, since the air vent valve 11 is always in the slightly open state as described above, the air reservoir 21 itself is hardly generated.

  One end of the drain pipe 12 is connected to the outlet (upper) side of the check valve 7 of the pumping pipe 6, and the other end opens to the inside of the cable duct 2. The drainage pool 22 that has been lifted on the side is removed or returned to the cable duct 2.

  The drain valve 13 is installed in the middle of the drain pipe 12 and adjusts the action of removing the drainage pool 22 by the drain pipe 12. The opening degree of the drain valve 13 in this embodiment can be adjusted manually (including mechanical ones as well as electronic ones), and the opening degree is normally fully closed. According to this configuration, when pumping by the pump 5 is not performed satisfactorily, the worker opens the drain valve 13 so that the drainage reservoir 22 at the outlet of the check valve 7 is removed. Since the back pressure applied from the outlet side is reduced, the pumping capacity is restored.

  The side groove 15 is a drainage channel provided on the surface of the earth, and the water W accumulated in the cable duct 2 discharged from the pumping pipe 6 is introduced and guided to a predetermined discharge location.

  As described above, the drainage system 1 according to the present invention includes the air vent pipe 10 and the air vent valve 11 on the inlet side of the check valve 7, and the water drain pipe 12 and the water drain valve 14 on the outlet side of the check valve 7. It is characterized by having. In this embodiment, the air vent valve 11 is appropriately operated by an operator, whereby the air reservoir 21 on the check valve 7 inlet side can be removed. Further, since the air vent valve 11 is always kept in a slightly open state, the occurrence of the air reservoir 21 is suppressed. Further, the drain valve 13 can be returned to the cable duct 2 by appropriately operating the drain valve 13 by the operator, so that the check can be performed when the side groove 15 is full. A situation in which a large back pressure is applied to the valve 7 and the check valve 7 does not open can be prevented.

  The drainage system 30 according to the present invention includes an air vent valve 35 and a water drain valve 36 instead of the air vent valve 11 and the water drain valve 13 according to the first embodiment. The air vent valve 35 and the water drain valve 36 are electromagnetic valves, and their opening degrees are automatically controlled by the ECU 40. The ECU 40 includes an inlet-side pressure sensor 41 that detects the pressure of the air reservoir 21 on the check valve 7 inlet side, and an outlet-side pressure sensor 42 that detects a back pressure (water pressure) due to the drainage reservoir 22 on the check valve 7 outlet side. The opening degree of the air vent valve 35 and the water drain valve 36 is automatically controlled based on this detection signal.

  As with the air vent valve 11 according to the first embodiment, the air vent valve 35 adjusts the air removing action of the air vent pipe 10 and is configured or controlled so as to be always in a slightly open state, that is, not completely closed. When the pressure in the air reservoir 21 becomes equal to or higher than a predetermined value by the inlet side pressure sensor 41, the air vent valve 35 has its opening increased according to the control signal of the ECU 40, and the pressure in the air reservoir 21 is lower than the predetermined value. In this case, the opening degree is decreased according to the control signal of the ECU 40, and the valve is slightly opened. Thereby, when the air reservoir 21 is generated at the check valve 7 inlet, the air vent valve 35 is automatically opened largely, and the air reservoir 21 is quickly removed. Further, as in the case of the first embodiment, the air vent valve 35 is always in a slightly opened state, so that the air reservoir 21 itself is hardly generated.

  Similar to the drain valve 13 according to the first embodiment, the drain valve 36 adjusts the action of removing the drainage reservoir 22 by the drain pipe 12 and normally has its opening degree fully closed. When the back pressure applied to the outlet side of the check valve 7 exceeds a predetermined value by the outlet side pressure sensor 42, the opening degree of the drain valve 36 is increased in accordance with the control signal of the ECU 40, and the back pressure is set to When the value is lower than the value, the opening degree is reduced according to the control signal of the ECU 40 and the valve is fully closed. As a result, when the back pressure to the check valve 7 increases due to the situation that the side groove 15 becomes full of water, the drain valve 36 is automatically opened, and the drainage reservoir 22 on the outlet side of the check valve 7 is removed. The Rukoto.

  As described above, according to the drainage system 30 according to the present embodiment, when the air reservoir 21 is generated on the check valve 7 inlet side, the air vent valve 35 is automatically opened, and the air reservoir 21 is removed. Further, as in the case of the first embodiment, the air vent valve 35 is always kept in a slightly open state, thereby suppressing the occurrence of the air reservoir 21 itself. Further, when a large back pressure is applied to the check valve 7 when the side groove 15 is full, the drain valve 36 is automatically opened, and the drainage reservoir 22 on the check valve 7 outlet side is removed.

It is a figure which shows the structure of the drainage system of the cable duct which concerns on Example 1 of this invention. It is a figure which shows the structure of the drainage system of the cable duct which concerns on Example 2 of this invention. It is a figure which shows the structure of the drainage system in the conventional cable duct.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,30 Drainage system 2 Cable duct 5 Pump 6 Pumping pipe 7 Check valve 10 Air venting pipe 11, 35 Air venting valve 12 Water venting pipe 13, 36 Water venting valve 15 Side groove 21 Air pool 22 Waste water pool 40 ECU
41 Inlet pressure sensor 42 Outlet pressure sensor

Claims (5)

A system for discharging water accumulated in a cable duct installed underground to the ground,
A pump that is installed inside the cable duct and generates pressure to push the water to the ground;
A pumping pipe connected to the discharge port of the pump and guiding the water pushed up by the pump to the ground;
A check valve that is installed in the middle of the pumping pipe and allows only a water flow in the direction from the cable duct to the ground;
An air vent pipe having one end connected to the inlet side of the check valve of the pumping pipe and the other end opened;
An air vent valve that is installed in the middle of the air vent pipe and changes a passage area of the air vent pipe;
A cable duct drainage system characterized by comprising: One end is connected to the outlet side of the check valve of the pumping pipe, and the other end is opened,
A drainage valve installed in the middle of the drainage pipe to change the passage area of the drainage pipe;
The drainage system for a cable duct according to claim 1, comprising:   The cable duct drainage system according to claim 1 or 2, wherein the air vent valve is configured or operated so as not to be fully closed. An air pool detection means for detecting the occurrence of an air pool on the inlet side of the check valve;
An air vent valve control means for controlling an opening degree of the air vent valve based on a detection result by the air pool detecting means;
The drainage system for a cable duct according to any one of claims 1 to 3, further comprising: Back pressure detection means for detecting water pressure applied to the outlet side of the check valve;
A drain valve control means for controlling the opening degree of the drain valve based on the detection result by the back pressure detection means;
The drainage system for a cable duct according to any one of claims 2 to 4, further comprising: