TW201510376A - Pump with cutting wheel - Google Patents

Abstract

A pump having a cutting wheel with wings (20a) the edges of which are configured as cutting edges (22) for cutting chippings (46, 46a) that are contained in the medium that is being pumped by the pump, the pump comprising a cutting plate (16) that forms counter cutting edges (18a) co-operating with the cutting edges (22), wherein the counter cutting edges (18a) have a wave-shaped contour with at least one nose (42) that projects in a direction opposite to the direction of rotation of the cutting wheel (20) and separates two concave bays (44, 44a) of the contour.

Description

Pump with cutting wheel

The present invention relates to a pump having a cutting wheel having a wing portion, the edges of which are configured as cutting edges for cutting debris contained in a medium being pumped by a pump The pump includes a cutting plate that forms a corresponding cutting edge that is co-operating with the cutting edges.

A pump of this type is known from DE 10 2008 031 842 B3 and is used, for example, in machine tools for circulating a lubricious coolant emulsion contaminated with metal debris. The pump is a centrifugal pump having, in addition to the radial impeller, an axial impeller disposed upstream of the radial impeller, the axial impeller being configured to cut the impeller and having a cutting edge at its upstream end, the cutting edges being The fixed corresponding vanes disposed axially in the suction passage cooperate such that debris and other contaminants that have been inhaled are cut and shredded.

One of the objects of the present invention is to increase the life of the pump.

According to the invention, this object is achieved by the feature that the corresponding cutting edge has an undulating profile having at least a projection in a direction opposite to the direction of rotation of the cutting wheel and separating at least two of the concave bottom plates of the profile a nose.

The rotation of the cutting wheel causes the vehicle to be twitched and with debris The eddy of the medium causes the debris to impinge on the contour of the corresponding cutting edge. When the debris caught by the flow in the circumferential direction or captured by the rotating wing of the cutting wheel hits the portion of the corresponding cutting edge that is inclined with respect to the radial direction, the debris has a tendency to slide along the inclined profile Until it finally reaches the bottom of one of the two bottom plates and is then cut by the cutting edge of the cutting wheel. Therefore, the bottom portion of the bottom plate corresponding to the cutting edge is subject to increased wear. However, since at least two such bottom plates are formed by the corresponding cutting edges, the wear is distributed to at least two different regions of the corresponding cutting edges, whereby the total wear is reduced and the corresponding service life is increased.

Useful embodiments and further developments of the invention are indicated in the dependent claims.

10‧‧‧ Shell

12‧‧‧ shaft

14‧‧‧Inhalation opening

16‧‧‧ cutting board

18‧‧‧ channel

18a‧‧‧ Corresponding cutting edge

20a‧‧‧wings

20‧‧‧Cutting wheel

22‧‧‧ cutting edge

24‧‧‧ shaft part

26‧‧‧Pre-cutting machine

28‧‧‧wings

30‧‧‧Base section

32‧‧‧Fixed corresponding blades

34‧‧‧blade carrier

36‧‧‧ openings

38‧‧‧ bolt

40‧‧‧ hook

42‧‧‧Nose

44‧‧‧ concave bottom plate

44a‧‧‧ concave bottom plate

46‧‧‧ Debris

46a‧‧‧ Debris

48‧‧‧ bottom point

50‧‧‧ bottom point

A‧‧‧ arrow

B‧‧‧ arrow

An embodiment example will now be described in conjunction with the drawings in which: Figure 1 is an axial cross-sectional view of the inlet portion of the pump in accordance with the present invention; Figure 2 is a perspective view of the inlet portion from below; and Figure 3 It is part of the cutting board in the enlarged view below.

The pump (which has been shown in one portion of the axial section in Figure 1) includes a housing 10 that rotatably supports the shaft 12 and forms a suction opening 14 that is coaxially disposed with the shaft. In another portion (which is not shown and located relatively upward), the outer casing 10 forms a pump chamber that houses a rotating impeller (eg, a radial impeller that is keyed to the shaft 12).

It should be assumed in the following that the pump has been mounted in a vertical orientation in a collection container (not shown) for lubricious coolant such that its suction opening 14 faces the bottom of the container and is immersed in the liquid contained in the container. . Therefore, the liquid will be drawn upward through the suction opening 14 by the pump.

The cutting plate 16 is inserted into the suction opening 14, which blocks a larger portion of the suction opening and leaves only four smaller passages 18. In the cross-sectional view of Fig. 1, the section indicated by line I-I in Fig. 2 extends away from the center of the suction opening such that one of the passages 18 is cut through.

The cutting wheel 20 is mounted on the shaft 12 above the cutting plate 16, and the blades of the cutting wheel are formed at the lower end thereof having a cutting edge 22 that is near the top of the passage 18 as the cutting wheel 20 rotates Move above and across the top of channel 18. In Figure 2, the serrated cutting edge 22 of the cutting wheel can be seen via the passage 18. The blades of the cutting wheel 20 (three blades configured with an angular separation of 120° in the example shown in Fig. 2) may be curved in the direction of rotation such that the cutting wheel 20 acts as a radial impeller. However, as appropriate, the blades may also have a helical shape such that the cutting wheel will act as an axial impeller.

As is often the case with machine tools, when the lubricative coolant from the machine tool being pumped back to the collection container contains debris from the treated workpiece (eg, steel scrap), such debris will The liquid is drawn together via the suction opening 14, and as the two pass through the channel 18, they will be captured by the cutting edge 22 of the cutting wheel and will be cut at the edge of the channel 18. In this way, debris can be prevented from becoming entangled and plugging or clogging the pump. In addition, the debris will be cut to a size that can be easily entrained in the coolant stream. This reduces the risk of clogging the downstream piping system.

The shaft 12 of the pump passes through a central bore of the cutting plate 16 and forms a shaft portion 24 below the cutting plate that carries a pre-cutting machine 26 for pre-cutting debris. As shown in Figure 2, the pre-cutting machine 26 has two wings 28, when viewed in a projection onto a plane orthogonal to the axis of the shaft 12 (the plane of the drawing in Fig. 2), the wings are configured and shaped such that they are rotated at 180° The axis of the shaft 12 is symmetrical. The wings 28 have a curved shape and extend initially radially outward from the base portion 30 (the wings are attached to the shaft portion 24 by the base portions), but then to the circumferential direction The curve is such that its free end is trailing in the direction of rotation (counterclockwise in Figure 2).

Although the wings 28 are symmetrical in the projection shown in FIG. 2, as can be seen in FIG. 1, the wings differ from one another in their axial configuration on the shaft portion 24. In particular, the base portions 30 of the two wings are axially offset relative to one another. In the condition of the left wing portion in Fig. 1, the base portion 30 is closer to the distal end of the shaft portion 24 (i.e., in the lower position), and in the condition of the right wing portion in Fig. 1, It is placed in a higher position so as to be closer to the cutting board 16.

Further, the left wing portion 28 in FIG. 1 is inclined downward toward its free end such that it forms an obtuse angle of about 135 with the axis of the shaft 12, while the other wing portion is inclined upward and thus forms an axis with the axis of the shaft 12. An acute angle of 45°.

Moreover, the wing portion 28 (in particular, the intermediate portion extending between the base portion 30 and the free end) is angled similar to the pusher wing portion such that the wing portions together provide upward guidance The suction forces the liquid medium to be displaced toward the suction opening 14.

Since the left wing portion 28 in Figure 1 is closer to the bottom of the container, it is particularly suitable for lifting relatively heavy debris that remains at the bottom of the container and transporting the debris toward the suction opening 14. Due to the tilting posture of the wing portion, it imparts a momentum to the liquid medium and debris, the momentum having an arrow substantially from FIG. The direction indicated by head A and therefore has a component that is directed radially outward. However, before the debris can move in the radial direction and is too far from the shaft portion 24, the debris enters an area where it is affected by the other wing portion 28 (the right wing portion in Figure 1). The other wing portion imparts momentum to the debris in the direction of arrow B and thus retreats in the direction towards the axis of the shaft portion 24 and thus in the direction of the passage 18 of the cutting plate 16. In this way, it can be said that the two wings 28 are operated in a work-sharing manner, wherein one of the wings has the task of lifting heavy debris from the bottom of the container and the other wing has a further conveying towards the suction opening 14. The task of the swarf, at the suction opening, will then be cut by means of the cutting wheel 20 in the passage 18.

However, due to the curved shape of the wing portion 28 and due to the inclined posture of the wing portions, the debris does not move directly from the bottom of the container to the passage 18, but rather instead is initially at the curved front edge of the wing portion 28 The drive is driven radially outward such that it enters the range of motion of the fixed corresponding blade 32 that is retained in the blade carrier 34 and extends parallel to the axis of the shaft 12 and the shaft portion 24.

In the illustrated example, the corresponding vanes 32 are formed by a rectangular plate (eg, duplex steel, hard metal, hardened tool steel) made of a hard material, each of which is formed to be guided It faces the fracture edge of the pre-cutting machine 26. When the peripheral portion of the wing portion 28 moves beyond the corresponding blade 32 with only a small distance, the debris entrained therewith (especially the long debris that tends to become entangled) is fragmented at the corresponding blade 32, This allows it to continue to move smoothly toward the passage 18.

In the illustrated example, the blade carrier 34 is shaped as a vertical wall having a U-shaped cross-section that flares outwardly in the shape of a funnel at the open side of the U. (Upward in Figure 2). When the pump is installed, for example, in the corner of the collection container, the open side of the blade carrier can face the center of the container such that the coolant can enter the suction region of the pump laterally. In this way, even when the distance to the bottom of the container is small, a large string of debris can still enter the range of the pre-cutting machine. The corresponding vanes 32 are distributed over a substantially semi-circular arc of the vane carrier at a uniform angular spacing and extend through the opening 36 (Fig. 1) of the vane carrier 34 and are removably mounted by means of bolts 38 (Fig. 2) such that The corresponding blade 32 can be replaced when the fracture edge wears.

Additionally, as can be seen in particular in Figure 2, each of the wings 28 has a hook-like, outwardly angled hook 40 at its free end. In this example, the hook 40 is shaped to form a step of the abutment surface 42, which extends generally orthogonal to the edge of the wing portion 28 and forms the origin of the relief 44 at the free end of the wing portion. When the debris impinges on the convex curved front edge of the wing portion 28 and slides radially outward along the wing portion, the hook 40 blocks the sliding movement to some extent, so that the debris is slightly prevented It is in the position at the outer end of the wing until the end of the wing moves beyond the broken edge of one of the corresponding vanes 32 and the debris hovering at the hook is fragmented. In this way, a particularly effective pre-crushing of the chips can be achieved.

A portion of the cutting plate 16 containing a single channel 18 has been shown in enlarged scale in FIG. It can be seen here that the corresponding cutting edge 18a extends in a substantially radial direction but has a curved wavy profile which is formed to protrude in a direction opposite to the direction of rotation of the wing portion 20a and to be concavely formed. The bottom plates 44, 44a are separated from each other by a nose 42.

In addition, Figure 3 shows a cross section of two debris 46, 46a which are entrained in the circumferential direction by the vortex of the medium and will therefore hit the corresponding cutting edge 18a in most cases and in the wheel being cut. Cutting edge 22 Sliding outward along this corresponding cutting edge before being captured. If the corresponding cutting edge 18a extends in a straight line, most of the debris will be cut by the cutting edge 22 only at the radially outermost point of the corresponding cutting edge. This will result in increased wear at this point. In contrast, in the case of the undulating profile shown in Figure 3, debris is preferably collected at the bottom of the two bottom plates 44, 44a. In a section that is inclined relative to the radial direction of the cutting edge 18a, the debris 46 will slide along the contour of the corresponding cutting edge in the direction toward the bottom point 48 of the bottom plate 44 or toward the bottom point 50 of the bottom plate 44a. The cutting edge 22, together with the nose 42, reduces the channel 18 to two enclosed areas, with the two debris 46, 46a remaining trapped in the enclosed areas. The debris will then be cut primarily at points 48, 50 so that the wear is distributed into these two points.

Optionally, the corresponding cutting edge 18a can have more than three bottom plates. The greater the number of bottom plates, the better the point of maximum wear will be distributed to the length of the corresponding cutting edge.

16‧‧‧ cutting board

18‧‧‧ channel

18a‧‧‧ Corresponding cutting edge

20a‧‧‧wings

22‧‧‧ cutting edge

42‧‧‧Nose

44‧‧‧ concave bottom plate

44a‧‧‧ concave bottom plate

46‧‧‧ Debris

46a‧‧‧ Debris

48‧‧‧ bottom point

50‧‧‧ bottom point

Claims (2)

A pump having a cutting wheel (20) having a wing portion (20a), the edges of the wings being configured as cutting edges (22) for cutting the medium being pumped by the pump Debris (46, 46a) contained in the pump, the pump comprising a cutting plate (16) forming a corresponding cutting edge (18a) cooperating with the cutting edges (22), the pump being characterized by The corresponding cutting edge (18a) has a contour that has an upward projection on the opposite side of the direction of rotation of the cutting wheel (20) and separates the two concave bottom plates (44, 44a) of the contour. At least one nose (42). The pump of claim 1, wherein the cutting plate (16) has a plurality of eccentric channels (18), the edges of the eccentric channels forming the corresponding cutting edges (18a).