US3446398A - Drainage equipment - Google Patents

Description

May 27, 1969 HORST .SCHINKE 3,446,398

DRAINAGE EQUIPMENT Filed Jan. 20, 1967 Sheet of s a'M/WW 1969 HORST SCHINKE DRAINAGE EQUIPMENT Sheet Filed Jan. 20, 1967 27, 196% HORST SCHINKE DRAINAGE EQUIPMENT Sheet 3 of3 Filed Jan. 20, 1967 United States Patent U.S. Cl. 222-63 8 Claims ABSTRACT OF THE DISCLOSURE Groundwater drainage equipment including a water tank communicating with two vacuum pumps which operate to cause at least a partial vacuum in the tank. The equipment also includes two submerged water pumps and a control system for bringing the vacuum pumps and Water pumps into operation in dependence upon the water level in the tank.

The invention relates to equipment for draining canal works, foundation trenches and the like, by means of vacuum wells, with a vacuum tank that is continuously evacuated by one or more vacuum pumps. The water present is collected in the vacuum tank, from which it is pumped intermittently with the aid of one or more pressure pumps. All the pumps used within and in conjunction with the equipment are controlled fully automatically by mechanical switching.

Equipment has already been proposed in which a vacuum or water-ring pump is used for removing air from a pipe system of the equipment and drawing the medium to be conveyed into the vacuum tank. In such equipment, the air is exhausted continuously as the Water is collecting in the tank. Once this is completely full, the vacuum pump is changed over by hand and a valve is opened to drain the tank. This intermittent action is repeated over and over again. The great drawback is that the pump requires constant attention and the manual change-over wastes time.

Other previously proposed equipment operates as just described, but the change-over is effected automatically. An electrical device is used to operate an air extraction valve and simultaneously to start a pump for drawing water from the tank, which is thus drained. Where water is present in large quantities, however, the plant can no longer be worked intermittently. Hence, the action of the electrically-controlled air valve is dispensed with and the plant as a whole can no longer work satisfactorily.

The intermittent employment of a pump normally providing suction for draining the vacuum tank has already been proposed. In this system, a vacuum equalisation pipe runs from the pump into the upper part of the vacuum tank, so as to remove air from the pump and enable the water to pass from the tank, through the suction pipe connection, to the pump. At high vacuum, however, these pumps are very ineflicient, since they are working against the vacuum and have to overcome the resistance of a constricted pipe connection. These centrifugal suction pumps are sensitive to even the smallest air bubble. The greatest danger is that air may gain access through the spindle seal and cut the pressure head in course of operation, in which event the tank will not be drained. This suction pump brought into action by the presence of a vacuum equalisation pipe has also been made intermittent in its action by partly mechanical control. This partly mechanical control, however, still operates in conjunction with auxiliary contactors, which are too delicate for the robust requirements of building-site work. This exist- 3,446,398 Patented May 27, 1969 ing partly mechanical control system is confined to about 40% of the capacity of the vacuum tank.

High vacuum pumps have also been proposed in which the vacuum pumps and water drainage pumps Work basically in parallel. In these, however, the pressure pump has to be designed as a self-priming pump and to have a correspondingly high lift. The disadvantage of these pumps working in parallel is the relatively heavy power consumption when the amount of water to be handled is small.

Finally, in which there has been proposed drainage equipment a water pressure pump is incorporated in the tank. The pump is driven by an electric motor situated outside the tank, the pump and its driving unit therefore being connected to each other by an extended pump spindle. The pump is mounted on a stand pipe. When pumps are used in this way, the stufiing box is below water level. The dilficulty of operating these pumps is that sand-bearing water flows in through the stufling box and that the bearings cannot be kept properly lubricated, because the lubricating grease is drawn out of the bearings by the high vacuum.

According to the present invention there is provided equipment for draining groundwater including a tank from which gaseous fluid can be continuously removed and at least one water pump the improvement which comprises casing means, vacuum-producing air pumps, drive means for the water and air pumps, and means for controlling mechanically the operation of said air pumps, said water pump being a submersible motor-driven water pump, and the water pump being fitted within the tank.

An embodiment of the equipment in accordance with the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawin gs, in which:

FIGURE 1 is a side elevation of the equipment;

FIGURE 2 is a vertical section along the line II-II in FIGURE 1;

FIGURE 3 is a partial longitudinal section, to an enlarged scale, through the equipment shown in FIGURE 1; and

FIGURE 4 shows a control disc together with arrange ments for transmission from a float linkage to the control disc segment in the equipment in accordance with the invention.

The vacuum tank 1 is mounted on a chassis 2. The tank 1 has a drain connection 3, which should preferably serve for draining the vacuum tank, but which also enables a further water pump to be connected. This drain connection 3 is fitted, according to circumstances, opposite the position occupied by the float when at rest, so that this can be locked in position by access through the drain connection, to prevent damage in transit.

Towards the top of the vacuum tank 1, two draw-off connections 4 are provided, the main pipe of a water-lowering system being connected thereto. The vacuum tank 1 is also provided with two pressure-pipe connections 5, with which are associated non-return valves 6, to make the vacuum tank air-tight.

From the pressure connections 5, pipes 7 with equalisation bores 8 lead to submerged motor-driven pumps 9a and 9b.

At the top of the vacuum tank 1 are an air exhaust connection 10, an automatic air valve 11 and a mechanical control 12. Air exhaust connection 10 consists of a chamber 13, which extends into the vacuum tank 1 and has a large number of apertures, 14. This chamber 13 contains a ball float 15, which, when vacuum tank 1 is overwater chamber 17 to a main pipe 18, which is in communication with two vacuum pumps 19a and 19b. The trap or chamber 17 has a drain tap 20.

When the vacuum tank 1 is over-full, the mechanical control 12 reaches its highest point and operates the air valve 11. A float projection 31 presses against a push-rod 21, which in turn lifts the obstructing ball 22. Air flows in and reduces the vacuum. This air is directed by Way of a pipe 23 into the trap or chamber 17, to relieve the vacuum therein. A float 24, which is rigidly attached to a float linkage 25, transmits the flotation movement via a spindle 26 to a control disc 27, on which the total range of the flotation movement, limited by the height of the vacuum tank, is converted to one segment. The control disc 27 carries projections 28, by which motor controls 29 are operated, Any desired number of pumps can be fully automatically controlled. As these projections 28 are differently spaced within the segments, the control paths are graded in such a way that fully automatic control is possible with a small number of control operations. While the range of changeover is graded for each pump, the maximum range of operation is retained.

One end 30 of the vacuum tank 1 is detachably secured to enable the constructional parts to be inserted from that end.

The mode of operation of the equipment is as follows: The two vacuum pumps 19a and 19b serve to extract the air from the pipes and draw the pumping fluid into the vacuum tank 1. Air is extracted continuously to form at least a partial vacuum. One or more vacuum pumps for maintaining a cushioning vacuum can be intermittently switched in automatically at the predetermined maximum graded level. The water collects in the vacuum tank 1. The water level also rises higher and higher within the casing of the submerged motor-driven pumps 9a and 9b and, because of the equalisation bore 8, in the pipe 7. When predetermined graded level a is reached, the pump 9a is switched on. When the water level is reduced by pumping to lower level It, the pump 9a is switched off.

There are vacuum-well installations in which considerable quantities of water occur, so that the capacity of the pump 9a is exceeded. In that case, the Water continues rising through the vacuum maintained in the tank 1 and reaches a second graded control level [2. This brings the second pump, 9b, into operation.

When the switching-on of the pump 9b succeeds in lowering the water, this falls to the predetermined graded level g, at which it switches the pump 9b off. The amount of water present, which is beyond the capacity of the pump 9a, thus does not fully absorb the additional capacity of the pump 9b. In accordance with what has been stated, control is fully automatic while the grading of the predetermined level reduces the number of control operations.

Should the water still continue to rise while the pumps 9a and 9b are running, that is a sign that the amount of water rising exceeds the capacity of both these pumps. At predetermined graded level c, the air pump 19a is put out of operation.

If the stoppage of the air pump 19a increases the capacity of water pumps 91: and 9b and if this exceeds the amount of water rising, the water level will sink back to predetermined graded level, f, at which it will bring the air pump 19a into action again. Here again, control is fully automatic and the grading of the level results in a minimum number of control operations. It, nevertheless, the operation of the air pump 1% alone results in a further rise of the water, this will again reach a predetermined graded level at which the air pump 1% will be stopped.

With air pumps 19a and 19b stopped, the entry of air bubbles carried along in the water may be expected to reduce the vacuum, increase the capacity of the pumps 9a and 9b and hence lower the water level to predetermined graded level e. At level e, the air pump 1% is restarted, the vacuum increases once more and the water again rises. Here again, there is thus fully automatic control with the least possible number of operations.

By the distribution of the air and water capacity among two or more pumps at a time, not only is high efiiciency possible, but also protection against the failure of a single pump.

As the pumps 9a and 9b are of the robust submerged type and are fitted at the lowest level in the tank 1, there is only slight deposition in the vacuum tank of this unit, to extent that the pumps carry sediment and slit away with the water.

As will be appreciated from the foregoing description it is desirable for the control lever of the motor control to be carried freely by the control disc until it jumps to the predetermined control position at the dead centre or control point. The control lever moves simultaneously clear of the guidance of the control disc, so that this disc can move on to carry out the system of graded switching. The motor control lever should preferably be guided by cams mounted on the control disc.

The control floats acts on a valve when at its highest flotation point. This valve opens under the pressure exerted by the float and allows air to flow into the vacuum tank, reducing the vacuum and increasing the water output. The air entering under the control of the valve should preferably be passed through a connecting pipe to a trap for water of condensation.

The air suction pipe may well take the form of a nozzle pipe in the vacuum tank. The air intake is so controlled that the water of condensation is deposited in a trap, from which it can be allowed to discharge.

The float linkage can be protected against damage in transit by a locking device operated through the drainage connection.

Both the water pump and its drive are housed in the vacuum tank, so that any leaks in the pump and/ or stand pipe are rendered harmless. The pump, moreover, has a generously proportional intake, increased resistance at the intake connection thus being avoided. The pump may be fitted with rotors equipped with paddles or passages to enable it to drive coarse grains of sand and the like along with the water, without the operation of the pump being adversely affected thereby.

A non-return valve inserted in the delivery pipe of the pump can be relied on to eliminate any risk of outside air being drawn in.

I claim:

1. Equipment for draining ground water including a tank from which gaseous fluid can be continuously removed and at least one water pump, comprising vacuum-producing air pumps mounted on the tank,

drive means for the water and air pumps, and

means for controlling mechanically the operation of said air pumps and the water pump in dependence upon the water level in the tank,

said pump being a submersible motor-driven water pump fitted within the tank and said tank, said pumps, drive means and control means being constructed as a unit.

2. Equipment according to claim 1 wherein said drive means includes electric motors and said control means includes a float movable within the tank in dependence upon water level, and switch means operable by said float to control said electric motors.

3. Equipment according to claim 1 wherein said drive means are electrically operated and wherein the control includes an arm carrying said float,

a spindle on which the arm is mounted,

a segmental member fast for rotation with the spindle,

a plurality of switches arranged in an arcuate array for actuation by the segmental member and connected to control operation of the drive means for said air and water pumps, and

means mounted on said segmental member and arranged to operate the switches at predetermined levels of the Water in said tank.

4. Equipment according to claim 2 further comprising an air valve mounted in the tank, and

means fast with said float for opening said air v-alve when the float reaches a predetermined height whereby air is admitted to the tank and the vacuum-producing air pumps are rendered ineffective.

5. Equipment according to claim 4, further comprising means defining an air exhaust connection from said tank to said vacuum-producing air pumps,

a condensed water trap in said air exhaust connection,

and

a pipe interconnecting the air valve and said trap Whereby air entering through the air valve is caused to pass "through said trap before entering the tank.

6. Equipment according to claim 5, comprising an opening from the body of the tank into the con densed Water trap,

a ball float arranged to close the said opening when the water level in the tank reaches a pre-set level, and means defining a perforated chamber holding captive said ball float.

7. Equipment for draining ground water including a tank from which gaseous fluid can be continuously re moved and at least one water pump comprising vacuum-producing air pumps mounted on the tank,

electric drive means for the water and air pumps, a float movable within the tank in dependence upon water level therein,

switch means operable by said float to control said drive means for said vacuum-producing air pumps and said Water pump,

an air valve mounted in the tank,

means rigid with said float for opening the air valve when the float reaches a predetermined height Where- -by air is admitted to the tank and the vacuum-producing air pumps are rendered ineflective,

means defining an air exhaust connection from the tank to the vacuum-producing air pumps,

a condensed-water trap in the air exhaust connection said trap having an opening into the tank, and

a pipe interconnecting the air valve and the trap Whereby air entering through the air valve is caused to pass through the trap before entering the tank,

said water pump being a submersible motor-driven Water pump fitted within the tank.

8. Equipment according to claim 7, comprising a ball float arranged to close the opening in the Water trap when the water in the tank reaches a pre-set level, and

means defining a perforated chamber holding captive said ball float.

References Cited UNITED STATES PATENTS 2,792,158 5/1957 Veitch et a] 222-385 X 3,040,785 6/1962 Grindle 222176 X 3,130,878 4/1964 Zimmermann 222318 3,136,485 6/1964 Bellows et al 222-176 X FOREIGN PATENTS 722,617 1/ 1955 Great Britain.

ROBERT B. REEVES, Primary Examiner. H. S. LANE, Assistant Examiner.

US. Cl. X.R. 222-67, 178, 385

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