US2924179A - Sinking and drainage pump units - Google Patents

Description

Feb. 9, 1960 K. G. ISAKSSON SINKING AND DRAINAGE PUMP UNITS 2 Sheets-Sheet 1 Filed April 17, 1956 Feb. 9, 1960 K. G. ISAKSSON smxmc AND DRAINAGE PUMP UNITS 2 Sheets-Sheet 2 Filed. April 1'7, 1956 2,924,119 SINKING AND DRAINAGE PUMP UNITS Application April 17, 1956, Serial No. 578,620

1 Claim. (Cl. 103-87) This invention relates to sinking and drainage pump units adapted to be immersed in a water body tobe drained, while resting on the bed of said water body. Such pump units may for instance be of the type including a watertight electric motor enclosed in a pump casing, so that the whole motor-pump unit may be immersed in the water. The pump unit is provided with an inlet opening at its lower end and the inlet opening is covered by a screen or a perforated plate to prevent the entry of large particles of foreign matter into the pump channels.

Pumps of this type have generally been suspended on wires or chains from a stand or the like, so as to keep the perforated bottom plate near the bottom of the cavity to be drained. However, at certain conditions of the soil, for instance loose sand or clay, it is often impossible to erect a stand and the pump unit must rest on the loose ground on the bed of the cavity. Under these circumstances the pump unit has been found to dig into the soil when running and moreover the pump unit is often very unsteady so that it will not stand upright for a long period. Furthermore, under certain conditions of the loose soil or when the bed of the cavity is covered by a layer of sludge the perforations tend to be choked up by the particles carried by the input water stream.

The main object of this invention is to provide supporting means for the pump unit, said supporting means permitting the pump to rest steadily on the ground, while keeping its bottom screen or perforated plate at a pre determined distance from the bed of the cavity to be drained, even if said bed consists of very loose sand, clay or the like.

According to the invention a sinking and drainage pump unit of the kind described above includes a support member in the form of a closed figure corresponding in shape substantially to the periphery of the screen or perforated plate secured to the screen or perforated plate and disposed in a plane parallel to and spaced from it so as to form an entry slot between the screen or perforated plate and the support member.

In use, the support member rests upon the bed of the cavity to be drained and the pump unit is steadily supported by the support member without any tendency towards digging into the bed.

The width of said slot is important and it has been found that in order to obtain satisfying results the width should be from 1 to 10 percent of the maxim-um transverse dimension of said screen or perforated plate. In order to obtain the best results the definite limits must be determined for each special case, taking into consideration the size of the pump and of the screen or perforated plate as well as the pump delivery capacity.

As by way of example it may be mentioned that with a diameter of the screen or perforated plate of about 16 inches and a delivery of about 265 gallons per minute the best result was obtained with a slot having a width of about 95 inch while a width of about W inch did not give the desired result.

Preferably, deflector members are provided within the Peed S tes. Paten 1 support member for guiding the water uniformly over the screen or perforated plate and preventing turbulences beneath said screen or perforated plate.

The invention will be described in the following with reference to the accompanying drawings which'illustrate preferred embodiments given as an example only without restricting the invention.

In the drawings:

Figure 1 is an elevational view partially in section of anembodiment of the invention,

Figure 2 is a similar view showing a somewhat modified bottom plate, and

Figure 3 is a plan undersize view showing deflector means according to my invention.

In Fig. l of the drawings 1 designates a casing enclosing a pump unit spaced from said casing 1 so as to form a water passage from the lower end of the casing 1 to a hose connection 2 at the top thereof. Said pump unit includes a centrifugal pump, generally indicated by 3 having its housing secured to said casing 1 by means of bolts 4. The pump housing supports a driving motor watertightly enclosed in a casing 5. A cable 6 containing electric conductors is passed through the top of said casings 5 and 1 to be connected to a suitable electric source.

An eye bolt 7 is screwed to the top of the casings 1 and 5 for lifting the pump device.

Said centrifugal pump 3 has a central inlet opening 8. Said inlet opening 8 is covered by a perforated screen or bottom plate 9. Said screen or bottom plate 9 may be somewhat cup shaped with low vertical margin portions which may also be perforated. However, the largest area for water to pass through is constituted by the proper bottom surface. The bottom plate may be plane as shown in Fig. 2 or concave as shown in Fig. 1, secured by bolts 10.

The under side of the perforated plate 9 is provided with deflector members 11 arranged in the form of a cross formed by ribs, flat ironbars or the like arranged perpendicular to the perforated plate. shown in Fig. 3. The length of the ribs or bars corresponds to the diameter of the perforated plate 9, and their ends are secured to a support ring or support member 12 of circular ring form, of a diameter substantially equal to the diameter of the screen or perforated plate 9. The member 12 is located at a distance from said perforated plate 9 so as to form an annular slot A therebetween. Although the support ring 12 of relatively large cross section is shown as a tube, it may be made of solid material and may have different cross sections provided it presents a suitably large bearing surface area against the ground. The radial or crossed bars 11 are shown as being welded to the perforated plate 9, but may be fastened in any other suitable manner, for instance by lugs 13 and bolts 14 (Fig. 2), or may be formed integral with said perforated plate 9.

It is to be noted that the crossed bars 11 may be replaced by other forms of deflector members for preventing turbulence under the perforated plate 9 while distributing the water uniformly over the whole perforated surface.

The device acts in the following manner when the support member 12 rests .on loose ground forming the bed of a cavity to be drained. At the beginning fine particles from the loose ground inside the support ring 12 are carried away with the water sucked by the pump so that a small hollow is formed within said support ring 12. The ring itself rests however on a layer undisturbed by the water stream. After this first removal of particles of sand, sludge, clay or the like, it has been found that any removal of such particles within said ring 12 ceases so that the supporting ring 12 rests on a compact portion of the ground and keeps the pump unit and its inlet screen 7 Patented Feb. 9,

Said cross is bestv or perforatedplate on; jconstant'leveliaboye the ground. 8 i

The ring 12 is drawn into close contact with theg'round by the action of the pumpgiso that all Water sucked in will pass through said annular slot A.-

-Altbough he inyention h'asbe e'n descrihed'yvith reference to an embodiment iniwhichlthe. screen or per-for such as oval or rectangular.

I claim:

A sinking and drainage pump innit comprising, in combination, a bellshaped housing having an open bottom face including an inlet opening a'centrifugal pump and its 8 a drivingrnotor enclosedin saidhousing, said unit being adapted to be entirely immersed in a liquid body to be drained; a screen of substantial transverse dimension covering the bottom face of saiclbell-shaped housing, an

endless bar-shaped ground engaging support member corresponding in shape to the periphery of said screen;

ated platefl andthe support member 12 are circular, it is equally applicable to pump units having other shapes,

di l fi w na Pete se ure to d n and said ground engaging support nie'n'aberrs'pecti'v'ly, therebyIholding the screen gnniformly spaced from the ground engaging support member and defining a substantially unobstructed endless entry slot with a height of be-, tween one and ten percent of the transverse dimension of the screen. i

j References emit thefileof this flzltiit QNITED sTA'rEsr TENrs mp!

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