The present invention relates to a pump. More particularly this invention concerns a vertical-axis macerating or grinder pump.
A typical grinder pump has a cutting head mounted on the lower end of a vertical pump shaft that carries the motor pump. A lower end of the shaft carries a cutting head that rotates across a pump intake opening formed in a bottom wall of the housing. An annular wall projects axially downward around the cutting head and protects the cutting mechanism.
Such a grinder pump is from U.S. Pat. No. 3,938,744. It has a pump formed by an eccentric rotor screw and a cutting head carried on the lower end of the pump shaft. Here, the cutting head is surrounded by a tubularly cylindrical wall of uniform height that protects the cutting head and projects downward past it. With such a pump, it has been shown that although the cutting mechanism is protected from mechanical damage, flexible solids that are drawn in, such as cleaning cloths and rags, are still not sufficiently cut up and clog the pump.
It is therefore an object of the present invention to provide an improved grinder pump.
Another object is the provision of such an improved grinder pump that overcomes the above-given disadvantages, in particular that comminutes flexible solids sufficiently so they do not clog the pump.
A grinder pump has according to the invention a housing having a bottom wall formed with an intake port, a drive shaft rotatable in the housing about an axis and projecting axially through the bottom wall, and a pump in the housing having a rotor connected to the shaft and operable to draw liquids and comminuted solids in through the port. A cutter head outside the housing at the bottom wall carries a blade juxtaposed with the bottom wall. The cutter head is fixed on and rotatable with the shaft for comminuting solids drawn into the intake port. An annular shield wall projects axially from the bottom wall around the cutter head and is formed with at least one axially projecting bump forming a valley constituting an intake opening through which liquid and solids can be drawn to the intake port by the pump.
Normally there are at least three angularly spaced such bumps forming at least three respective valleys that are open axially outward away from the bottom wall.
Such a shield wall having a varying height, with one, two or more bumps that project downward, sufficiently protects the cutting mechanism from mechanical damage and furthermore significantly improves the cutting action of the cutting mechanism. Flexible solids, such as cleaning cloths and rags, are put into vibration by the flows produced by the shield wall, and thereby delayed in surges, so that slowed-down, controlled guidance to the cutting head takes place. Furthermore, the bumps ensure that the motor pump can no longer be set up vertically. A pump that can be set up vertically can easily be knocked over and thereby damaged.
An optimal behavior of the in-flow and further prevention of a vertical setup is also achieved in that the bumps have different heights relative to one another. For this purpose, it is also proposed that the bumps are distributed asymmetrically over the circumference of the lower edge of the shield wall, in such a manner that fewer or no bumps are provided on one half of the circumference than on the other half.
A particularly advantageous embodiment of the shield wall is achieved if the lower edge of the shield wall has the shape of a wave-shaped constant curve having one or two wing-like bumps that project downward. Preferably, it is proposed that the shield wall has a height in the region of the lowest point of the valley, which amounts to 1/20 to 1/2 of the height of the bumps. Alternatively, the lowest point of the valley can lie at the level of the lower face of the cutting plate that has the pump intake openings. Here, the two bumps should lie diametrically opposite one another.
Preferably, it is proposed that the bump(s) is/are V-shaped, U-shaped, or W-shaped. Instead, the bump can be formed by a slant of the lower edge of the shield wall.
Preferably, the cutting head has two diametrally opposite arms that slide closely over the cutting edges of two diametrally opposite the pump intake openings with their cutting edges. Secure conveying of solids is achieved if the pump is an eccentric screw pump whose rotor is between the cutting head and the drive motor.
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
As seen in
The pump has a rotor 4 in the form of an eccentric screw, which is coaxially attached at the lower end of a motor shaft 14 (
Thus rotation of the shaft 14 will operate the pump formed by the rotor 4 and stator 5 and will also rotate the two-bladed cutting head 7. The pump 4, 5 will draw liquid (and comminuted solids as described below) into the ports 9 and expel them through a lateral output 15 above the rotor 4 and stator 5. The cutting head 7 has two blades that slide over the planar lower face of the plate 8 and forces material to be ground against the edges of the ports 9 so as to comminute this material. The rotation speed of the head 7 is great compared to the speed at which solids are aspirated into the ports 7, so these solids are chopped into small pieces that the pump 4, 5 can easily handle.
The cutting head 7 is coaxially surrounded by a basically circular annular shield wall or collar 10 that forms a downward extension of the pump housing 1 and protects the cutting head 7 from mechanical damage. In prior-art grinder pumps, the shield wall 10 has the same axial height H all around. In the pump according to the invention however, the height H of the shield wall 10 varies angularly and smoothly around its circumference. Here, the shield wall 10 forms one, two, or more bumps 12 or feet having the height H and that project downward beyond the cutting head 7 with their downwardly directed apices. The lower edge 11 of the shield wall 10 is a wave-shaped curve, preferably having up to four wing-like bumps 12 that project downward. The bumps 12 have different axial heights H. This ensures that the pump does not stand perfectly perpendicular to a planar surface it is set on. Furthermore, for this purpose, the bumps 12 are spaced asymmetrically or nonuniformly around the circumference of the lower edge of the shield wall 10, such on one half of the wall 10 there are fewer (or no) bumps 12 than on the other half.
Valleys 13 are formed between the bumps 12 that form openings 10a that permit lateral or radially inward intake of the dirty household waste water with its solids (also including cleaning cloths and rags, among other things). Thus these solids get to the cutting head not only from below, but also from the side through these openings 10a. In this way the solids can get to the blade of the cutting head 7 for comminution and aspiration with liquid through the port.
The cutting head 7 forms in the dirty water flow that is drawn in a whirlpool-like eddy that vibrates is put into vibration by the bump(s) 12, which vibrations guide the solids to the cutting head in surges, thereby significantly improving the cutting performance. As a result of the eddy, the solids move, particularly slide along on the edge 11 of the shield wall, and perform an up and down movement in doing so, thereby causing them to be cut up even more reliably, without clogging the cutting mechanism and the intake openings.
Number | Date | Country | Kind |
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202013009716.7 | Nov 2013 | DE | national |