WO1995006819A1

WO1995006819A1 - Vane-cell pump

Info

Publication number: WO1995006819A1
Application number: PCT/DE1994/001001
Authority: WO
Inventors: Joachim Stegner
Original assignee: Imk Ingenieurkontor Für Maschinenkonstruktion Gmbh
Priority date: 1993-09-01
Filing date: 1994-08-30
Publication date: 1995-03-09

Abstract

The invention relates to a vane-cell pump, especially for viscous media, e.g. concrete, consisting of a pump housing containing a rotor with radially movable vanes, a conveyor section for the medium between the inlet and outlet apertures, a return section between the outlet and inlet apertures and curved tracks in the region of the inlet and outlet apertures to guide the vanes from the conveyor to the return sections and vice versa. In order to prevent the rotor from being blocked, the vanes (21 to 24 and 21' to 24') are stepped down at least in sections in the head region on the side in front of their vane guide (211, 221, 231, 241) in the direction of movement in the basic rotor body (20) and the boundary edges opposite the direction of movement of the rotor (2) of the inlet (13) and outlet apertures (14) take the form of strippers (132, 142).

Description

Vane pump

The invention relates to a vane pump, in particular for viscous media, for example concrete, consisting of a pump housing that receives a rotor with radially movable vanes.

with a conveying section for the medium between the inlet opening and the outlet opening, in which the vanes protrude from their vane guide and are supported sealingly on the inner surface of the pump housing,

with a return section between the outlet δff

and the inlet opening in which the vanes are largely recessed in the vane guides in the base body of the rotor and the diameter of the return section of the pump housing in this area corresponds approximately to the outside diameter of the rotor base body, and

- With curved tracks in the area of the inlet and outlet opening, for guiding the wings from the conveying section to the return section and vice versa.

A vane pump of the type mentioned is i.a. known from DE-GM 88 05 078. The vanes lying opposite one another in one plane and sliding in radial vane guides of the rotor have a uniform thickness and a uniform length in pairs.

The guide curves are designed according to the principle of a curve of the same diameter. It is scanned in a form-fitting manner by the head surfaces of wings lying opposite one another in pairs, which have essentially the same distance from one another. The guide curve has two rest areas. The latching areas are arranged between the inlet opening and outlet opening in the delivery area on a large diameter and between the outlet opening and inlet opening on a smaller diameter.

Separate guide curves are provided in the sections between the locking areas, which leave the inlet and outlet openings free.

Such a pump is indeed very well suited for the conveyance of air or liquid media, but its disadvantage is that when granular and also pasty media are used, jamming occurs, particularly where the outer edges of the blades are the inlet opening or outlet opening leave in the direction of the rest areas.

The wings approach the locking level at an acute angle or as a tangent. Grains or solid components of the medium to be conveyed, which lie on this edge in front of a wing, only have the chance to escape to the outside in the discharge channel.

If they come to lie in such a way that they are pressed towards the inside of the apex encountered, they are clamped between the wing or the rotor base body and the leading surface, in particular in the region of the guide curves of the pump housing. The rotor is blocked and the pump becomes unusable.

DE Gb 19 88 878 proposes a vane pump for liquid media in which a vane of constant length is mounted in the rotor base body in a radially movable manner and moves in an eccentric space to the rotor axis. To ensure an optimally sealing deposit, the outer surfaces of the wing are reduced by recesses in the form of a groove, that they have an optimal sealing effect even at different system angles. Such a vane pump is not suitable for pumping viscous media, in particular concrete, because this narrow surface can also lead to blockage if the smallest grains of sand get into the conical gap at the outlet from the inlet and outlet openings.

It is also known to provide, on a vane pump for liquids, radially movable vanes in the rotor, the front ends of which are offset at an acute angle from the running direction. Even a vane pump designed in this way cannot be used for conveying thick and granular media, because K 1s get stuck between the inner surface of the eccentric conveyor and the inclined surfaces of the vane. The obtuse-angled transitions from the inlet and outlet openings to the eccentric delivery chamber additionally support this defect.

The rotary lobe pump for conveying concrete disclosed with the German utility model 66 091 99 has a stationary scraper at the outlet of the inlet and at the outlet of the outlet opening for the concrete to be conveyed relative to the rotating piston. However, such a design of the pump is unsatisfactory with regard to its performance, since the cement sucked into the arcuate free space of the rotary piston does not dissolve out again in the region of the outlet channel at the usual speeds.

Even a controlled scraper does not remedy this deficiency, which is pushed into the free space on the inner guide of the rotary piston and is intended to lead the cement to the outside. Such a pump is inefficient and involves many uncertainties, especially with regard to the scraper.

The rotary piston attaches concrete to its radial surfaces, which hardens and then influences the functioning of the scraper up to complete inoperability.

For the reasons mentioned, although there was an urgent desire to use these simple pumps for conveying concrete (see also DE 680 917), significantly more complicated pumps were used for this purpose in the long term.

Pumps of this complicated type are either piston pumps or peristaltic pumps with displacement rollers.

On the one hand, such pumps are expensive and costly, and they also require a high level of power for their operation - even when idle.

Screw pumps are also widely used, the outer screw flight of which consists of a hard but elastic material. For the purpose of sealing the gap to the inner, metallic worm gear, this outer worm gear has to lie against the long length under pretension.

Considerable amounts of energy are required to overcome the sealing forces required for this alone. On the other hand, these large sealing forces lead to extremely high wear on the screw bodies in the presence of the smallest grains in the medium to be conveyed.

For this reason, the use of pumps of this type for conveying liquid concrete or mortar has so far been limited and expensive. The cleaning of the pumps used to date from the liquid concrete residues always required dismantling of the entire pump and separate cleaning of each individual component of the pump with the aid of water.

Another disadvantage, particularly of the screw pumps, is that for each grain size range

Liquid concrete different pumps with different dimensions of the screw flights must be used.

In addition to the adapting conversion, there was always the

Danger of loss of information regarding the installed screws or the to be promoted

Medium often came to accidents, blockages or increased wear.

The aim of the invention is to remedy these shortcomings.

The object of the invention is to design a vane pump for conveying concrete or cement mixes in such a way that blockages of the rotor by granular components of the medium to be conveyed are avoided, that sealing elements which are difficult to move and rub are reduced to a minimum and that the delivery rate to be applied is essentially determined only by the mass of the medium per unit of time, its internal friction and the delivery head.

According to the invention, this object is achieved by using a vane pump with the special features defined in claim 1. The essence of the effect of the inventive elements is that grains of different sizes, between the wing and the respective scraper edge at the end of the inlet or outlet openings, can deflect on several sides. If the grains dodge inwards, they collect in the step-shaped section of the respective wing. The excess mass accumulating there is basically pressed to the circumference of the rotor and is carried there by the scraper into the outlet channel. The mass within the step is exchanged with the appropriate design of the transitions during the next conveying process, so that there is always soft mortar or concrete ready for picking up stripped grains.

The design according to claim 2 focuses the step on the area of greatest risk of blocking and ensures that no grains can be positively clamped in front of the scraper edge of the outlet opening.

The positioning of the cam track and the section of the step-shaped recess of the wing according to claim 3 enables mortar that accumulates and compresses between the curve, wing and scraper edge to escape to both sides and into the step-shaped recess.

With the embodiment according to claim 4 it is also ensured that mortar or concrete located there, when larger grains are pushed into the space of the step, is pressed into the space where the scraper is effective.

The design according to claim 5 is proposed for relatively coarse-grained concrete mixtures. The large number of large grains are only pushed into the outlet channel in the same cycle in the rarest of cases. If these grains are not carried away by the concrete to be subsequently conveyed, this option remains the only form of cleaning the step. This type of return can be combined with an appropriate design of the return channel with the pressure relief on the inside of the wing.

An expedient and simple design of the return duct is obtained if it is located in at least one of the front-side boundaries of the rotor housing.

It is sufficient if this return channel is formed by recesses open on one side in a removable cover or a disc that can be exposed. If the one-sided openings of the return channels face the end faces of the rotor, edges of the blades can support the conveying of the concrete in these channels.

It is particularly advantageous with regard to low wear if the return channels in disks consist of a stable, elastic material (e.g. polyurethane).

If necessary, the pump housing and the channels can be easily cleaned while the pump is in operation and by introducing water instead of the medium to be conveyed.

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawings:

1 shows a section through the pump housing transverse to the rotor axis;

2 shows a section through the cover, approximately along line II-II, of the pump housing with part of the rotor, the guide curves and a disk provided with channels; 3 shows a section analogous to FIG. 1 of a modified rotor and blade design;

4 shows an enlarged illustration of a cut wing in the stepped section immediately in front of the scraper of the outlet opening and

5 shows a section along the line V-V in Fig. 4th

The vane pump consists of a pump housing 1 with a bearing for the rotor 2.

The movement space for the rotor 2 and the vanes 21, 22; 23, 24 is delimited on the one hand by a cylindrical conveyor section 11 with a large diameter in relation to the rotor axis 25 and a second cylindrical return section 12 with a small radius, likewise in relation to the rotor axis 25.

These two sections 11, 12 are diametrically opposed to one another and - measured via the rotor axis 25 - are always at the same distance from one another. The wings 21,22; 23, 24, which are diametrically opposed to one another, are separated from one another, but - apart from small tolerances - have such a dimension that they can be guided between the cylindrical surfaces of the sections 11, 12 in an almost form-fitting manner.

In the area of the inlet 13 and the outlet opening 14 of the pump housing 1, the radial guidance of the vanes 21, 22; 23.24 accomplished by curves that the wings 21.22; 23, 24 according to laws of motion that are as free of jolts and jerks as possible with controllable Accelerations and decelerations lead from the larger radius to the smaller radius in the area of the outlet opening 14 and from the smaller radius to the larger radius in the area of the inlet opening 13.

Here too, the principle is chosen that the distance between the current guide surfaces 213 of the wings 21, 22; 23.24 - measured over the rotor axis 25 - always remains the same.

The principle of the inevitable curve control with the aid of a curve of constant effective diameter is used.

The number of wing pairs 21, 22 and 23.24 is advantageously 2. Depending on the size of the pump and the required delivery rate, more wing pairs can also be used.

In some places, this pump has been specially designed for use as a pump for conveying concrete or mortar.

The wings 21,22; 23, 24 in the embodiment according to FIG. 1 have a clearly stepped recess on their front side in the direction of movement and on the outside.

This recess serves to ensure that when one of the wings 21, 22; 23, 24 and the scraper edge 142 at the end of the outlet opening 14 grain-like structures are positioned, the possibility exists that they can be pressed both upwards into the outlet opening 14 and downwards into the area of the step. Blocking of the rotor 2 is prevented. The space created by the step is regularly full of mortar or concrete. The grains or mortar parts additionally pressed into this space by the scraper 142 make it necessary for other, preferably flowable, masses to be able to escape there. As a rule, these evasive mass parts are pressed in the direction of the outlet opening 14 and stripped off.

But it can also happen that the concrete cannot escape to the outside. Thin liquid components are therefore pressed through gaps between wings 21 ... 24 and wing guides 211 ... 241.

Due to this circumstance, a pressure and also a concrete layer builds up under the wings 21... 24, which can considerably impede the functioning of the pump.

To avoid this deficiency, in the example according to FIG. 1 in the area of the base body 20 of the rotor 2 near the tapping edge 142 of the outlet opening 14, an access 411 to a return channel 41 is provided, which receives the pressed-out concrete mixture and into the open or better through the opening 413 leads back into the inlet opening 13 of the pump.

This return channel 41 is expediently designed as a groove-shaped recess in the disk 4, which delimits the end region of the rotor 2. The fact that each time a wing 21.22; 23,24 concrete mix is pressed into the step-shaped recess, the concrete is continuously moved in this return channel and cannot dry in it.

In practice, even with the measure described, it is unavoidable that between the radially inner surface of the wings 21, 22; 23, 24 and the surface of the rotor base body 20 opposite this likewise also accumulates concrete. It is therefore expedient that, especially where this space is the smallest, a lateral access 412 to the return duct 41, which could also be referred to as a pressure relief duct, is provided. This can ensure that the concrete that collects there does not get stuck and harden.

A somewhat different variant of the vane pump is shown in FIG. 3, which is specified by the detailed representations in FIGS. 4 and 5.

In the area of the outlet opening 14, the cam track 141 'for controlling the blades 21', 22 ', 23', 24 'is arranged approximately in the middle of the rotor 2 (FIG. 5).

The cam track 141 'is designed in such a way that the front edge of the wing 21', 22 ', 23 •, 24' has already reached the outer diameter of the rotor base body 20 before the largest grains can get caught between it and the scraper edge .

This is certainly the case when this point is reached about three to eight mm before the scraper ante.

The arrangement of a step-shaped recess 23a on the wings 21 ', 22 •, 23', 24 'is only necessary in this case in the region of the cam track 141'. The scraper edge 142 is missing here.

The granular concrete stripped from the curved path 141 'by the wing 21', 22 ', 23', 24 'cannot escape upwards into the outlet opening 14 and inevitably leads to blockages.

This is where the step-shaped design 23a of the wings 21 ', 22', 23 ^• , 24 'helps, at least in the region of the curved track 141'. The problem of reducing the excess pressure in the area of the step-shaped recess 23a is overcome on the one hand by the recess 23a being wider than the curved path 141 '. Mortar can also escape to the outside.

In addition, the arrangement of a lateral return channel 41 'in the sense described above is sufficient for reducing the pressure and the mortar from the area of the wing guide.

The design of the return duct 41 'in the form shown in Fig. 3 has proven to be useful.

The wide, ring-shaped free space, which should be tightly closed on the inside towards the bearings and on the outside towards the delivery chamber, dissipates pressure and concrete without problems and avoids excessive friction losses and wear zones.

It is advantageous if the sealing surface between the rotor 20 and end wall 4 towards the delivery chamber is kept somewhat wider in the region of the highest pressure.

The return channels 41 can be provided on both plane sides of the rotor 2.

In the case of vane pumps with small and medium delivery rates, however, it is sufficient to incorporate this channel in the cover 3 to cover the pump housing 1.

For cleaning purposes, only the cover 3 needs to be loosened and the concrete can be washed out with a water jet.

For reasons of wear in the area of the cover 3 and the easy removal of any hardened concrete residues, the part of the cover 3 into which the return channels 41 are incorporated is designed as a separate disk 4. This disc 4 is preferably made of an elastic but stable material, hard rubber or polyurethane.

The vane cell pump is cleaned after its use has ended simply by interrupting the supply of concrete and supplying water in its place. After a very short time, all cavities of the pump are freed of concrete residues and the pump can be shut down until the following use.

Before the following use, however, the cover 3 of the pump housing 1 should be removed from time to time in order to check that no residues have been preserved and hardened in the return channels 41 in which the water flow is somewhat lower.

The situation at the scraper edge 132 of the inlet opening 13 is similar to that at the scraper edge 142 of the outlet opening 14.

It must also be ensured here that the between the apexes of the scraper edge 132 there and the front edge of the respective wing 21, 22; 23, 24 clamped grains can dodge on both sides.

The space above the wing 21,22; 23, 24 - in this position - has therefore been expanded and the end of the inlet opening is literally designed as a scraper edge 132 (FIG. 1).

It has proven to be expedient to arrange the inlet opening 13 at the top of the pump, because under these circumstances the concrete that accumulates there is repeatedly classified into the process by the action of gravity and thus cannot harden. If this position of the pump cannot be realized, it is expedient to provide a vibrating element (not shown) at this point, which regularly congests the concrete stowed in this throat for the purpose of conveying it into the effective area of the wings 21, 22; 23.24 pushes.

In FIG. 3, an additional, elastic wiper 133 is provided in front of the normal wiper edge 132.

This additional scraper 133 can avoid coarser grains with its scraper edge and then pushes them into the movement space of the wings.

The power consumption of such a vane pump is only insignificantly influenced by the friction coefficients on the pump caused by technology.

The design of your drive can therefore be limited to the actual delivery rate, which depends on the delivery rate per unit of time, the specific weight of the medium to be pumped, the delivery head and the friction conditions in the piping system and within the medium.

The design of the interior of the vane pump may well differ from the example described.

It is crucial that the conditions described are ensured in the area of the scraper edges, that a return channel is provided in the manner described and that the guide surfaces of the blades are not brought into an acute angle to the guide surfaces in the pump housing if the concrete contains grains in these areas can collect mixture. List of the reference symbols used

Pump housing delivery section return section

Inlet opening 1 curved track 2 wipers, edge with an angle smaller than 90 ° 3 wipers, elastic

Outlet opening 1, 141 'cam track 2 wipers

rotor

Basic rotor body, 22, 23, 24 F2 blades ', 22', 23 ', 24' blades a recess, step-shaped

1,221,231,241 sash guide 3 rotor axis guide surface

cover

disc

Boundary surface, 41 'return channel 1 access 2 access 3 opening

Claims

claims

1. Vane pump, especially for viscous media, e.g. Example concrete, consisting of a pump housing, which holds a rotor with radially movable blades,

with a return section between the outlet opening and the inlet opening, in which the vanes are largely recessed in the vane guides in the base body of the rotor and the diameter of the return section of the pump housing in this area corresponds approximately to the outer diameter of the rotor base body, and

with cam tracks in the area of the inlet and outlet opening, for guiding the wings from the conveying section to the return section and vice versa, characterized in that

that the blades (21 to 24 and 21 'to 24') in their head area, on the front side in the direction of movement opposite their blade guide (211, 221, 231, 241) in the rotor base body (20) are at least partially stepped and

that the boundary edges of the inlet (13) and outlet opening (14) directed against the direction of movement of the rotor (2) are formed as an edge with an angle of less than 90 ° (132, 142).

2. Vane pump according to claim 1, characterized gekenn¬ characterized in that the vanes (21, 22, 23, 24) are stepped at least in the effective area of the cam track (141, 141 ') effective in the area of the outlet opening (14) and that the cam track (141, 141 ') is designed such that the front edge of the vanes (21, 22, 23, 24) is positioned at least at a distance from the step depth in front of the scraper (142) close to and within the outer diameter of the basic rotor body (20).

3. Vane pump according to claim 1 and 2, characterized in that the cam track (141 ') at least in the region of the outlet opening (14), together with the associated step-shaped section of the wing (21,22, 23,24) axially approximately in the center of the rotor (20) is arranged.

4. Vane pump according to claim 1 to 3, characterized in that the cam track (141, 141 ') is narrower than the step-shaped section associated with it

Wing (21,22,23,24).

5. Vane pump according to claim 1 to 4, characterized in that the step-shaped sections of the wing (21,22,

23, 24) extend at least to one of the end faces of the rotor (2) and that on at least one of the end faces of the rotor (2),

- on one of the fixed boundary surfaces (40),

- Within the outer diameter of the basic rotor body (20),

- Near and in front of the scraper (142) of the outlet opening (14) access (411) to a return channel (41) is provided.

6. Vane pump according to one of claims 1 to 5, characterized in that the vane guides (211,221,231,241) in the rotor (2) are laterally open in a manner known per se and that in the radially inner region of the laterally open vane guides (211,221,231,241) accesses (412) a return duct (41, 41 ') are provided.

7. Vane pump according to claim 5 and 6, characterized in that the return channel (41) is designed as a groove open on one side in the cover (3).

8. Vane pump according to claim 5 to 7, characterized in that the return channel (41) with its accesses (411,

412) in a disc (4) made of stable, elastic

Material is arranged.

9. Vane pump according to claim 1 to 8, characterized in that the stripper (132) of the inlet opening (13) in

Distance an elastic wiper he (133) is arranged.