RU231566U1 - Device for dewatering with needle filters - Google Patents

Abstract

The utility model relates to the field of construction, namely to installations for dewatering and drainage during excavation and other construction work on the construction of foundations, hydraulic structures, various underground structures and communications. The device for dewatering with needle filters includes a housing with an inlet, outlet water and outlet air pipes, a drainage pump installed inside the housing and the pressure pipe of which is connected to the outlet water pipe, as well as a vacuum pump, the suction pipe of which is connected outside the housing to the outlet air pipe. The pressure pipe is equipped with a bypass valve. The technical result is the exclusion of water locking in the housing when starting the operation of the device for dewatering.

Description

The utility model relates to the field of construction, namely to installations for dewatering and drainage during excavation and other construction work on the construction of foundations, hydraulic structures, various underground structures and communications.

The presence of groundwater in the area of excavation work (digging foundation pits, driving trenches and tunnels) significantly complicates the execution of works, increases the risk of collapse of pit and trench slopes due to their sagging, landslides. Strengthening slopes with various structures (for example, sheet piling) does not solve the problem of eliminating the filling of the pit with groundwater, when continuation of works (concreting, laying communications) is not possible at all. In this case, water-lowering units with needle filters are used to locally lower the groundwater level.

A device for dewatering and drainage is known (Electric vacuum unit VPK "Shtorm-M", company "GruntVacuum", https://gruntvacuum.ru/katalog-oborudovaniya/vakuumnaya-ustanovka-shtorm-m/, accessed on 08/27/2024). The device includes a housing with inlet and outlet pipes, a drainage and a vacuum pump. The drainage pump is installed inside the housing and its pressure pipe is connected to the outlet pipe. A check valve is mounted in the outlet pipe. When the drainage pump is running, the check valve opens and does not interfere with the discharge of water. When the drainage pump stops, the check valve closes due to back pressure, preventing vacuum loss. The vacuum pump is connected to an opening made in the housing and designed to pump air out of the housing cavity. After the device is deployed at the work site, the needle filters are hydraulically immersed in the ground and connected to the collector pipeline, which in turn is connected to the inlet pipe of the unit. The outlet pipe of the unit is designed to drain water to a specified location (for example, to remote reservoirs through a system of connected pipelines/hoses). When the unit is turned on, the vacuum pump begins to pump air out of the housing, which creates a vacuum in it. The created vacuum leads to the suction of a water-air mixture from the soil into the housing (drained soil always contains air along with water, the amount of which can change as the soil dries out) through the inlet pipe of the unit. As the housing is filled with the water-air mixture, air is released from it - air bubbles rise upward. At the same time, the drainage pump is turned on, starting to pump water through the outlet pipe. The air separated from the water-air mixture is pumped out by the vacuum pump.

However, the initial moment of starting the operation of the described device selected as a prototype is accompanied by a high risk of failure of the drainage pump and, consequently, the device for lowering the water level as a whole, which is due to the following. At the beginning of the operation of the vacuum pump, a vacuum is created in the cavity of the housing, i.e. the pressure gradually decreases. The sucked-in groundwater begins to fill the housing. The internal cavity of the drainage pump communicates with the cavity of the housing only through the water intake opening located in the lower part of the drainage pump, thus it is possible to consider the internal cavity of the drainage pump and the cavity of the housing as communicating vessels. Therefore, it would be expected that as the water level in the housing increases, the water level in the internal cavity of the drainage pump will also increase synchronously. However, this is prevented by the air trapped in the internal cavity of the drainage pump. When the housing is filled with water, the drainage pump is turned on, but its impeller is in the air (in the internal cavity of the drainage pump), as a result of which the drainage pump operates idle and water is not pumped out of the housing, i.e. the groundwater will be trapped in the housing. Long-term idle operation of the drainage pump can lead to its failure (the motor winding will overheat and burn out if there is no cooling by the pumped water). Filling the internal cavity of the drainage pump with water is possible when the air pressure inside and outside the drainage pump is equalized, which does not happen, since the internal cavity of the drainage pump (from the inlet water intake to the outlet water pipe) is completely isolated from the "flow" of air into the space around the drainage pump. As a result, in the device selected as a prototype, it is necessary after filling the housing with water manually reduce the vacuum in the housing (for example, open the tap connecting the housing space to the atmosphere), after which the pressure in the housing space will become higher than the pressure in the internal cavity of the drainage pump, water will fill the internal cavity of the drainage pump, the impeller of the drainage pump will be covered with water and pumping will begin.

The technical challenge is to create a compact device that provides effective dewatering.

The technical result consists in eliminating the locking of water in the housing, which ensures pumping out water without additional manual manipulations when starting the operation of the device for water lowering.

The technical result is achieved in that in a device for lowering water, including a housing with an inlet, outlet water and outlet air branch pipes, a drainage pump installed inside the housing and the pressure branch pipe of which is connected to the outlet water branch pipe, as well as a vacuum pump, the suction branch pipe of which is connected outside the housing to the outlet air branch pipe, according to the utility model, the pressure branch pipe is equipped with a bypass valve.

Supplying the discharge branch pipe of the drainage pump with a bypass valve ensures equalization of air pressures outside the drainage pump (in the internal cavity of the housing) and inside the drainage pump (in the internal cavity of the drainage pump) at the moment of starting the operation of the device for water lowering. Creating identical air pressure values eliminates the locking of groundwater in the housing and ensures pumping out water without additional manual manipulations when starting the operation of the device for water lowering and, therefore, ensures more efficient operation of the device for water lowering.

The claimed device is illustrated by drawings, where Fig. 1 shows a schematic diagram of the device (side view), Fig. 2 shows a diagram of the device (top view), Fig. 3 shows a diagram of the device (view A, valve open), Fig. 4 shows a diagram of the device (view A, valve closed).

The following positions are shown in the figures:

1 - body;

2 - inlet pipe;

3 - water outlet pipe;

4 - air outlet pipe;

5 - drainage pump;

6 - pressure pipe;

7 - vacuum pump;

8 - bypass valve;

9 - check valve;

10 - locking disk;

11 - water intake hole.

Depending on the operational requirements, the design of the device for water lowering may be different. Below is one of the possible implementation options of the declared device, intended to illustrate its technical essence and operating principle, but does not limit the scope of legal protection.

The device for lowering the water level includes a housing 1 with an inlet 2, an outlet water 3 and an outlet air 4 branch pipes. A drainage pump 5 is installed inside the housing 1, the water intake opening 11 of which is connected to the internal cavity of the housing 1, the pressure branch pipe 6 of which is connected to the outlet water branch pipe 3. A vacuum pump 7 is installed outside the housing 1, for example, on its side wall, the suction line of which is connected to the outlet air branch pipe 4. The pressure branch pipe 6 is equipped with a bypass valve 8, including a shut-off disk 10. A check valve 9 is mounted on the outlet water branch pipe 3, designed to shut off the pipeline when the device is not operating and to prevent air from entering the internal cavity of the housing 1 from outside.

The device works as follows.

Along the perimeter of the zone to be dewatered (e.g. along the perimeter of a pit), hydraulically immerse needle filters into the ground, connect them to a collector pipeline, which in turn is connected to the inlet pipe 2 of the dewatering device. The outlet water pipe 3 is connected to a discharge pipeline, through which the pumped water enters the discharge zone, for example, into a sewer, a drain, etc. When the dewatering device is first started (when there is no water in housing 1), the control automation system first turns on the vacuum pump 7, under the action of the created vacuum, water begins to enter housing 1, its level rises. Under the action of the created vacuum, the check valve 9 is closed. At this point, the bypass valve 8 is open: its shut-off disk 10 is deflected. The open bypass valve 8 ensures equalization of the air pressures outside the drainage pump 5 (in the internal cavity of the housing 1) and inside the drainage pump 5 (in the internal cavity of the drainage pump) at the moment of starting the operation of the device for lowering the water level. Water begins to fill the internal cavity of the drainage pump 5, displacing the air located in it through the bypass valve 8 into the housing 1. When the water in the housing 1 rises above the level (threshold) of switching on the drainage pump 5, it switches on and begins to supply water to the outlet water pipe 3, as a result of the created large excess pressure, the check valve 9 opens and water is discharged through the outlet water pipe 3. Water rushes into the lower opening of the valve 8 and lifts the shut-off disk 10, thereby closing the bypass valve 8, which prevents water leakage through the valve opening and, as a consequence, loss of pump performance. The control automation system switches off the drainage pump when the water level in the housing drops to the switch-off threshold. In this case, the threshold for turning off the drainage pump is set so that the pump impeller remains in the water and, when the drainage pump is turned on again, water is pumped out regardless of the state of the bypass valve.

Thus, the utility model allows for the creation of an effective compact dewatering device by eliminating water locking in the housing and ensures water pumping without additional manual manipulations when starting the dewatering device.

Claims (1)

A device for dewatering with needle filters, comprising a housing with an inlet, outlet water and outlet air branch pipes, a drainage pump with the possibility of being switched off by a control automation system, installed inside the housing, and the pressure branch pipe of which is connected to the outlet water branch pipe, as well as a vacuum pump with the possibility of being switched on by a control automation system, the suction branch pipe of which is connected outside the housing to the outlet air branch pipe, characterized in that the pressure branch pipe is equipped with a bypass valve.