US3269326A

US3269326A - Wellpoint system

Info

Publication number: US3269326A
Application number: US409131A
Authority: US
Inventors: Jack T Culleton; Frank V Flesher
Original assignee: PACIFIC PUMPING CO
Current assignee: PACIFIC PUMPING CO
Priority date: 1964-11-05
Filing date: 1964-11-05
Publication date: 1966-08-30
Anticipated expiration: 1983-08-30

Description

1966 J. T CULLETON ETAL 3,269,326

WELLPOINT SYSTEM 2 Sheets-Sheet 1 Filed Nov. 5, 1964 INVENTQR. JACK T. CULLETON FRANK V. ELESHER @4M MQM FM ATTQQNEYS Aug. 30, 1966 J. 'r. CULLETON ETAL 3,269,326

WELLPOINT SYSTEM Filed Nov. 5, 1964 2 Sheets-$heet 2 INVENTOR. 34 JACK T. CULLETON BY FRANK v. FLESHER F/G. 6 allmmw ATTORNEYS United States Patent 3,269,326 WELLPGINT SYSTEM Jack T. Culleton, Hayward, and Frank V. Flasher, Oakland, Califl, assignors to Pacific Pumping Company, Oakland, Calif., a corporation of California Filed Nov. 5, 1964, Ser. No. 4tl9,131 6 Claims. (Cl. 103113) This invention relates to a pumping apparatus particularly adaptable for use with wellpoint systems for dewatering excavations.

A wellpoint dewatering system generally consists of a series of wellpoints that are located in the ground at spaced apart intervals around an excavation. Each wellpoint extends below the maximum water level that can be tolerated for the excavation and each has a riser and a suitable joint to facilitate its connection to a main header above the ground level. The latter is connected to a pumping system which removes the water that collects in the header and discharges it to a suitable drainage area, thereby keeping the excavation free of water so that construction can take place. An inherent problem with wellpoint systems is that a large amount of air is combined with the water that reaches the header due to the irregularities of subterranean drainage patterns. Unless this air is removed, it will adversely affect the operation of the centrifugal pump connected to the header. Air in the water being pumped can cause cavitation and resultant wear in the pump, or in some cases a loss of prime resulting in inefficient or completely ineffective operation. Heretofore, wellpoint systems were utilized having a vacuum pump which attempted to remove the air from the water entering the main centrifugal pump. However, such systems were ineflicient and unreliable because under certain conditions the vacuum pump was unable to cope with large amounts of air and to operate at high capacity for long periods of time.

An important object of the present invention is to provide an improved pumping apparatus for use with wellpoint systems that is capable of long runs of efficient trouble-free operation without the need. for standby operators and maintenance personnel.

Another object of the invention is to provide a pumping apparatus for a wellpoint system that provides a more positive control over air separation and evacuation, and therefore, produces a uniform high vacuum and a steady ground water discharge.

More specifically, an object of the present invention is to provide a wellpoint pumping system wherein a heavy duty, high capacity output, wet type vacuum pump can be used with unusual effectiveness, efficiency and reliability to remove air from the water before it enters the main centrifugal pump.

Another object of the present invention is to provide a pumping apparatus for a wellpoint dewatering system wherein a constant supply of filtered Water is recirculated to the vacuum pump to keep it continuously sealed and primed during operation of the system, and this recirculated water is constantly cooled by the water being drawn from the wellpoint system header. This objective is accomplished in my invention by means of a unique arrangement that includes a dual compartment tank, one compartment containing the filtered water being recirculated to the vacuum pump, and the other having an inlet and outlet to allow passage therethrough of the water being discharged.

Still another object of my invention is to provide a unique vortex chamber in a pumping apparatus for a wellpoint system which receives the water from the wellpoint and quickly separates all air from it by a centrifugal action, and allows the air to be removed therefrom through a valve that is controlled by the water level in the chamber.

Other objects, advantages and features of the invention will become apparent from the following detailed description presented in accordance with 35 U.S.C. 112.

In the drawing:

FIG. 1 is a diagrammatic view in cross section showing a typical wellpoint dewatering system for an excavation;

FIG. 2 is a schematic view partially in section showing a pumping system embodying the principles of the invention;

FIG. 3 is a view in section taken along the line 33 of FIG. 2;

FIG. 4 is a view in perspective of one form of pumping apparatus according to the invention;

FIG. 5 is an enlarged view in elevation and in cross section showing the combined heat exchanger and cooling water storage tank for the apparatus shown in FIG. 4;

FIG. 6 is a view in cross section showing the rotor assembly of a typical wet type vacuum pump.

In the drawing, a pumping apparatus 10 embodying the principles of the invention is shown schematically in FIG. 2, while FIG. 4 shows the various components of the apparatus in a practical arrangement that is particularly well adapted for use with wellpoint dewatering systems. To best illustrate the function and utility of the invention in its pumping application, FIG. 1 shows a typical excavation dewatering system which generally comprises a series of wellpoints 11 that are sunk vertically in the ground at spaced apart intervals around an excavation 12. The inlet head 13 for each wellpoint is located well below the bottom 14 of the excavation and the upper ends thereof are connected by a riser to a header 15. The latter is connected to the inlet of the pumping apparatus which discharges the water through a drain pipe 16. Many other arrangements and variations of wellpoint systems can, of course, be devised, but FIG. 1 illustrates the basic principle of such systems wherein the water drains through the soil and into the wellpoint inlet heads and thereafter collects in the header. Because of the irregularity of subterranean soil patterns, and hence in the water drainage rates produced underground, a large amount of air is usually combined with the water as it reaches the header. In order to pump the water from the header, the air combined with it must be removed, and this creates one of the problems which is solved by the present invention.

The apparatus 10, as shown schematically in FIG. 2, comprises a main centrifugal pump 17 which is driven by a suitable power means such as an electric motor or a stationary gas or diesel engine. The pump 17 is a heavy duty type capable of long duty cycles at high capacity. A characteristic of such pumps is that once filled with water and pumping steadily, they will continue to operate satisfactorily until air is admitted or some other cause breaks the suction. To maintain the pump prime, all air must be removed from the water fed to it. Thus, in the present invention the inlet 18 of the main pump 17 is connected to the outlet 19 of a deaerating tank 26, the inlet 21 to the latter being connected to the wellpoint header 15.

The tank 20 has a generally cylindrical shape, with a vertical axis, the inlet 21 thereto being located near its bottom end and directed toward one side of said axis. Thus, water from the header 15 enters the tank tangentially and as it swirls around, centrifugal force pushes it radially outwardly toward the tank wall and causes a separation of air from the water. The outlet 19 for water from the tank is also tangentially located on the opposite side thereof so that only water and no air passes therethrough to the pump 17 when the water level is maintained above a minimum level in the tank.

The air that is separated from the water must be evacuated from the tank so that even though the water flow rate into the tank decreases, no air will go to the main pump 17. This removal of air from the tank is accomplished by a vacuum pump 23 which is preferably driven by a separate power source such as an electric motor.

Connecting the inlet of the vacuum pump 23 and the top of the tank is a conduit 24 through which the air evacuated from the tank passes to the vacuum pump. An automatic shutoff valve 25 of the conventional type is provided at the opening to the conduit 24 in the top of the tank so that when the water therein reaches a predetermined maximum level, the valve 25 will close and prevent any water from going to the vacuum pump. The valve 25 is actuated by a float 26 that extends downwardly into the tank 20. When the water recedes below the float, the valve automatically opens and the evacuation of air from the tank continues.

Due to occasional turbulence of the water entering the tank 20 from the header 15, the float 26 could be inadvertently raised and improper opening and closing of the valve 25 would result. To prevent this undesirable valve action from occurring, a turbulence suppressing baffle plate 27 is provided within the tank. This plate is located in a substantially horizontal transverse position above the inlet 21 and below the float 26. As shown in FIG. 3, a series of radially and circumferentially spaced apart openings 28 are provided in the plate which are sufficient to allow a flow through the plate without causing any back pressure. Yet, the flow upward is sufliciently restricted so as to prevent momentary actuation of the float 26 and its valve due to erratic surges of turbulence of the water in the tank.

In accordance with the invention, the vacuum pump 23 is the wet type which is a well known centrifugal displacement type of pump that is commercially available. Generally, such a pump, as shown in FIG. 6, consists of a round, multi-blade rotor 30 revolving freely in an elliptical casing 31 partially filled with liquid. While this type of vacuum pump itself is not novel, its use in combination with the other components, as will be described, is important in the present invention because of the new and unusual results produced. It will be necessary, therefore, to describe further the operation of a wet type vacuum pump. A series of curved rotor blades 32 are attached to and project radially from the pump hub 33 and form, with the side shrouds 34, a series of pockets or buckets 35 around the periphery. The rotor 30 revolves at a speed that is high enough to throw the liquid out from the center by centrifugal force. This results in a solid ring of liquid revolving in the casing at the same speed as the rotor, but following the elliptical shape of the casing. This alternately forces the liquid to enter and recede from the buckets in the rotor at high velocity. Describing a complete cycle of operation in -a given chamber or pocket of the rotor which is initially full of liquid, as the rotor 30 turns the liquid due to centrifugal force following the casing, withdraws from the rotor chamber 36, and pulls air in through an inlet port 37 located at the root of the rotor blade and connected with the pump inlet. As the liquid is thrown outward from the chamber in the rotor 30 it is replaced with air. As rotation continues, the converging wall of the casing 31 forces the liquid back into the liquid chamber 36, compressing the air in the chamber and forcing it out through a discharge port 38 that is connected with the pump discharge. The rotor chamber 36 is now full of liquid and ready to repeat the cycle which takes place twice in each revolution. It has been well estab lished that wear in the aforesaid wet vacuum type of pump is reduced to a minimum because there is no metal to metal contact in the pump interior. There are no valves, I

because the bottoms of the rotor blades passing over the port openings 37 perform the valve function.

To maintain the operation of the wet type vacuum pump 23, a relatively small but continuous flow of water must be supplied to it. Moreover, this water must be cool to prevent vapor problems, and also free from dirt or grit to avoid wear in the pump components. In the present invention the problem of supplying cool, dirt-free water to the vacuum pump 23 so that it can operate at high capacity for long trouble-free periods is solved by means of a unique dual compartment tank 40. As shown in FIG. 2, and in greater detail in FIG. 5, the tank is preferably, though not necessarily, cylindrical in shape. In the embodiment shown, an internal fluid tight wall member 41 divides it into two separate compartments. Connected to a first compartment 42 near its bottom side is the outlet 43 of the main centrifugal pump 17 and in the end wall of the compartment is an outlet 44. The second compartment 22, adjacent the compartment 42 contains the clean water which is circulated through the vacuum pump 23. Accordingly, a pair of inlet and

outlet pipes

45 and 46 are connected between appropriate locations on the vacuum pump and the tank compartment 42, thereby providing a recirculating flow path for clean water.

Connecting the first compartment 42 of the tank 40 and the second compartment 22 is a conduit 47. Since the fluid pressure in the first compartment is always greater than in the second compartment, there is a constant flow pressure in the conduit 47 toward the second compartment. The amount of this flow is controlled by a valve 48 which is fixed in the end of the second compartment. Any suitable form of valve may be used here which will open the conduit 47 and allow flow into the second compartment whenever the water level therein decreases, as it will, over a period of time due to normal vapor leaks. A typical valve arrangement, shown in FIG. 5, includes a float 49 mounted on an arm 50 that extends into the second compartment 22 and is linked to a butterfly valve member 51 at the opening of the conduit into the second compartment.

Connected in the conduit 47 between the first and second compartments is a suitable filter 52 for removing dirt or sediment from the wellpoint water being supplied to the second compartment 22. Thus, the Water that is retained in the second compartment 22 of the tank 40, which is continuously recirculated to the vacuum pump 23, is free from dirt, and wear of the vacuum pump due to foreign particles is eliminated.

To enable the water level in the second compartment 22 to be checked at any time, I may provide a sight gauge 53 on one side thereof. Such a gauge may comprise simply a transparent tubular section vertically supported between upper and lower tubular members fixed to the tank walls.

In FIG. 4 an embodiment 10a of my pumping apparatus is shown as it appears when assembled as an integrated assembly for use on a construction site for dewatering purposes. The various components of the apparatus are conveniently mounted on a frame 55 which is supported by a pair of skids 56. Near its midpoint an upright frame section 57 has a bracket 58 to which a cable can be connected to lift the apparatus and maneuver it into the desired position. Mounted conveniently near one end of the frame is the upright cylindrical deaerating tank 20 having its tangential inlet 21 which may be connected to a wellpoint header, and a similarly tangential outlet 19 that is connected to the main centrifugal pump 17 Mounted on the frame 55 near the main pump 17 is the vacuum pump 23. In the embodiment shown, the main pump and the vacuum pump are separately driven by electrical motors 59 and 60, respectively, although it is apparent that other power means could be utilized to drive the pumps, if desired.

The air line 24 from the vacuum pump 23 extends to the top of the deaerating tank 20 so that all air separated from the Water being pumped is drawn to the vacuum pump and discharged before it can get to the main centrifugal pump 17 The main pump will thus never lose its prime and will pump continuously at a high capacity, even though the water from the various wellpoints in the system is initially mixed with a high percentage of air or gas. As shown, I may provide a gauge 61 on the top of the tank 20 to indicate the pressure within the tank during operation of the apparatus. When the air-free water in the vortex tank 20 rises to a predetermined level at which only air-free water can be discharged to the main pump, the valve 25 at the upper end of the tank closes the air line 24 to the vacuum pump, thereby preventing any water from getting in it. When the water level falls below the aforesaid predetermined level, the valve will automatically open so that air will again be removed from the deaerating tank to the vacuum pump. The vacuum pump is constantly in operation so that there is never any chance of air getting to the main centrifugal pump even though the flow in the header connected to the tank is erratic.

The dual compartment tank 40 is mounted conveniently above the main pump 17 in the embodiment 10a, the outlet of the pump being connected to its underside near the end forming the first tank compartment 42. The outlet 44 from the first compartment 42 for the water being discharged from the pumping apparatus extends from the end wall of the tank so that it can be conveniently coupled to a drainage hose or pipe. As discussed previously, the water maintained in the second compartment 22 of the tank 40 is continuously recirculated to the wet vacuum pump 23. This recirculating water which normally increases in temperature is cooled in the tank 40 by the continuous flow of wellpoint water from the main pump 17 which circulates through the adjacent first compartment 42. "Dhus, the tank 40 not only serves as a storage tank that furnishes a constant supply of clean water to the vacuum pump, but it also serves as a heat exchanger to remove heat from the recirculating vacuum pump water.

From the foregoing, it should be apparent that the present invention provides an improved pumping apparatus for wellpoint systems and the like. By providing an apparatus that automatically cleans, cools and replenishes water to a supply tank, a wet vacuum type pump can be utilized which has a high air removal capacity, thereby increasing the efficiency and reliability of the main pump. The entire apparatus is capable of long periods of troublefree operation and requires a minimum of maintenance, thereby eliminating the need for standby operators.

To those skilled in the art to which this invention relates, many changes in construction and Widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

We claim:

1. In a pumping apparatus for use with wellpoint dewatering systems, the combination comprising:

a main pump and means connected thereto for driving a deaerating tank having an inlet connected to a header of a wellpoint system and an outlet connected to the main pump inlet;

a wet type vacuum pump of the type requiring a constant supply of liquid to produce a suction pressure at the pump inlet and means for driving said vacuum pump at a constant speed;

an air suction line connected at one end to said vacuum pump inlet and at the other end to the upper end of said deaerating tank;

a supply tank for water required to operate said wet vacuum pump;

inlet and outlet conduits connected to said vacuum pump and said supply tank;

means for utilizing the water discharged from said main pump for cooling the water in said supply tank being supplied to said set type vacuum pump.

2. In a pumping apparatus for use with wellpoint dewatering systems, the combination comprising:

a main pump and means connected thereto for driving a deaerating tank having a tangentially located inlet connected to a header of a wellpoint system and an outlet at the lower end thereof connected to the main pump inlet;

a wet type vacuum pump of the type requiring a constant supply of liquid to produce a suction pressure at the pump inlet and means for driving said vacuum pump rotor at a constant speed;

a supply tank for water required to operate said Wet vacuum pump;

inlet and outlet conduits interconnecting said vacuum pump and said supply tank;

means for circulating the water discharged from said main pump adjacent to the water in said supply tank to extract heat therefrom.

3. In a pumping apparatus for use with wellpoint dewatering systems, the combination comprising:

a main pump and means connected thereto for driving a deaerating tank having a tangentially directed inlet connected to a header of a wellpoint system and a tangential outlet near the lower end thereof connected to the main pump inlet;

a wet rotary type vacuum pump of the type requiring a constant supply of liquid to produce a suction pressure at the pump inlet and means for driving the vacuum pump rotor at a constant speed;

an air suction line connected at one end to said vacuum pump inlet. and at the other end to the upper end of said deaerating tank;

a dual-chamber tank including a first chamber for water required to operate said wet vacuum pump, including inlet and outlet conduits connected to said vacuum pump and said supply tank;

and means forming a second chamber in said tank and including an inlet connected to the outlet of said main pump and a discharge outlet, and thereby circulating the water discharged from said main pump adjacent to said first chamber to extract heat from the water therein.

4. In a pumping apparatus for use with wellpoint dewatering systems, the combination comprising: 1

a main pump and means connected thereto for drivin a deaerating tank having a tangentially directed inlet connected to a header of a wellpoint system and a tangential outlet near the lower end thereof connected to the main pump inlet;

a generally elongated tank located on a level above said vacuum pump;

a fixed water-tight partition in said tank forming first and second compartments adjacent each other, said first compartment having an inlet connected to the outlet of said main pump and adapted to discharge water through an outlet, said second compartment having a pair of conduit lines connected to and providing a circulation of water for said vacuum pump;

a conduit interconnecting said first and second compartments;

a valve in said conduit adjacent said second compartment for controlling the flow thereto of water from said first compartment;

7 8 whereby the water level in said second compartment References Cited by the Examiner is constant-1y maintained at a predetermined level UNITED STATES PATENTS and is cooled by the circulation of water in said first 1 910 775 5/1933 Saxe 1O3 113 5 :f Z d l 1 fil 5 2,178,994 11/1939 Inglis 103113 he evice as escribed in c aim 4, inc uding ter means in said conduit for removing dirt from the Water FOREIGN PATENTS sup-plied from said first to said second compartments. g

6. The device as described in claim 4, including a 7'98094 7/1958 ig: g

perforated transverse plate located above said inlet and 10 outlet in said deaerating tank for controlling water tur- MARK NEWMAN, Primary Examine!- bu-lence therein. H. F. RADUAZO, Assistant Examiner.

Claims

1. IN A PUMPING APPARATUS FOR USE WITH WELLPOINT DEWATERING SYSTEMS, THE COMBINATION COMPRISING: A MAIN PUMP AND MEANS CONNECTED THERETO FOR DRIVING IT; A DEAERATING TANK HAVING AN INLET CONNECTED TO A HEADER OF A WELLPOINT SYSTEM AND AN OUTLET CONNECTED TO THE MAIN PUMP INLET; A WET TYPE VACUUM PUMP OF THE TYPE REQUIRING A CONSTANT SUPPLY OF LIQUID TO PRODUCE A SUCTION PRESSURE AT THE PUMP INLET AND MEANS FOR DRIVING SAID VACUUM PUMP AT A CONSTANT SPEED; AN AIR SUCTION LINE CONNECTED AT ONE END TO SAID VACUUM PUMP INLET AND AT THE OTHER END TO THE UPPER END OF SAID DEARATING TANK; A SUPPLY TANK FOR WATER REQUIRED TO OPERATE SAID WET VACUUM PUMP; INLET AND OUTLET CONDUITS CONNECTED TO SAID VACUUM PUMP AND SAID SUPPLY TANK; MEANS FOR UTILIZING THE WATER DISCHARGED FROM SAID MAIN PUMP FOR COOLING THE WATER IN SAID SUPPLY TANK BEING SUPPLIED TO SAID SET TYPE VACUUM PUMP.