DE102009010037A1 - Arrangement for reducing pressure - Google Patents

Abstract

The invention relates to an arrangement for reducing the pressure during delivery of a pulp suspension (S) by means of a turbine (5, 6), which comprises at least one impeller (22) through which the pulp suspension (S) flows and which is mounted on a rotatable shaft (21). has. In this case, pressure pulsations in the pulp suspension (S) should be reduced in that the turbine (5, 6) is designed as an axial turbine, wherein the impeller (22) is flowed through parallel to the shaft (21).

Description

The The invention relates to an arrangement for reducing the pressure at the promotion of a pulp suspension by means of a Turbine, which flows through at least one of the pulp suspension and has impeller mounted on a rotatable shaft.

The Pulp suspension is usually through a closed system, in particular through pipelines and apparatus. It may be necessary to print at certain points to reduce.

Usually this is done via throttling regulatory organs, in particular Valves or valves.

there the pressure energy at the throttle point becomes useless heat implemented. Furthermore, this can lead to pressure pulsations in the stream the pulp suspension come, which negatively on the other Process, in particular the production of a fibrous web affects.

In the DE 10 2007 001 848 Therefore, a turbine is proposed for energy.

The The object of the invention is the pressure pulsations in the pulp suspension to minimize when using a turbine.

According to the invention was solved the problem by the fact that the turbine as axial turbine is executed, wherein the impeller flows parallel to the shaft becomes. Axial turbines dampen pressure fluctuations considerably Extent and reduce the pressure in a relatively narrow tolerance range regardless of whether the impeller is running or blocked is.

Around to impede the propagation of pressure fluctuations through the turbine and the emergence of new pressure fluctuations through the axial turbine especially in terms of their strength should minimize the impeller at least eight, preferably at least ten rotor blades have.

This can be further improved by the fact that the impeller at least 12, preferably has at least 14 rotor blades.

to Use of the pressure energy of the pulp suspension should be the shaft be coupled to a generator, preferably an asynchronous generator.

The usual The generator that feeds into a power grid is not just used to generate energy but also to compensate for hydraulic instabilities.

about The mains frequency of the power grid is the asynchronous generators Speed of the impeller kept substantially constant.

at higher pressure of the pulp suspension becomes more energy generated and fed into the power grid. If the pressure falls from, then the fed-in energy decreases accordingly.

in the The result is an improved damping of pressure pulsations in the pulp suspension stream.

Because of the sensitivity of the system is beneficial when the turbine preferably in the field of treatment of the pulp suspension or in the constant part of a machine for producing a paper, Carton, tissue or another fibrous web is arranged.

Special There are advantages when the pulp suspension from a Headbox of a machine for producing a paper, cardboard, Tissue or other fibrous web or if the pulp suspension in the form of the reject of a Drucksortierers is passed to the turbine.

following the invention should be closer to two embodiments be explained. In the attached drawing shows:

1 : a plant scheme;

2 a schematic cross section through an axial turbine and

3 : a schematic cross section through another axial turbine.

According to the in 1 shown constant part of a machine for producing a paper-paperboard tissue or another fibrous web is a pulp suspension S in the usual way by mixing a thick stock suspension 4 produced with a dilution liquid and then has substantially the same for the operation of the headbox 1 the paper or board machine 2 desired consistency at this point.

It is known that headbox consistencies range between 0.5 and 2%, usually around 1%. The dilution liquid that is at a mixing point 3 is supplied, comes in the example shown here mainly from the first white water 15 So in the Formierbereich the paper or board machine 2 accumulated water. It is often referred to as white water I (SWI) in difference to the later on the paper machine resulting white water, which contains much less fines.

It is known that such white water 15 Inter alia, with a considerable proportion of air and possibly other gases is mixed. The white water 15 is collected below the paper machine sieve and drained sideways. In the open channels used for this purpose, a large part of the air contained can already escape. Nevertheless, it is often useful to take other measures known per se and not shown here for venting.

After mixing thick matter suspension 4 and dilution liquid, the pulp suspension S via a fuel pump 9 here in a closed system (ie without open containers or laid paper) to the headbox 1 guided. In this case, the remainder of remaining impurities in the usual way by a Cleaneranlage 13 and a sorting unit 11 excreted.

To the pressure in the cleaner system 13 not to be too high, can be between the acceptance line 18 the cleaner system 13 and the inlet to the sorting unit 11 to increase the pressure of another fuel pump 10 be installed. Of course, the effort that must be done for these hydrocyclones and sorters will depend on the raw materials as well as the quality requirements of the paper produced.

If z. B. the thick matter suspension 4 made of waste paper, there may still be sand and small plastic parts. The fuel pump 10 can be designed so that gas is sucked out in its central inlet region.

Especially with modern headboxes 1 For their operation a strong overpressure is needed, which can be up to 10 bar or even higher. This requirement results from the fact that the pulp suspension S at the exit from the headbox 1 through the nozzle 17 to be brought to a relatively high speed and from the fact that turbulence increasing internals in and at the headbox 1 can produce a significant pressure loss.

For various reasons, it has been found that the operation of a headbox 1 and the related paper or board machine deduction of a subset 19 from the headbox 1 required.

In the operating state, this subset 19 quite about 10% of the headbox 1 correspond to supplied amount of suspension. This subset 19 is practically under the same pressure as in the supply line 16 to the headbox 1 , When using the method according to the invention, this subset 19 in a turbine 5 passed, in which the pressure is reduced.

This mechanical power is generated, which, as in the example shown here via a clutch or a transmission 8th to the fuel pump 10 passed on or via a generator 7 can be used for power generation.

To the interaction of pump 10 and turbine 5 to coordinate with each other, for example with different subsets 19 , the turbine can 5 be provided with adjustable vanes.

The sorting unit 11 here includes a pressure sorter 12 where a partial flow 20 is derived as a reject.

As is known, the reject flow of a pressure sorter 12 formed by a partial flow, which has not passed the sieve. At the point where the pressure sorter 12 installed in this system, this causes the pressure of this partial flow 20 also very high, possibly even higher than in the headbox 1 can be. Should this partial flow 20 (Reject) in a secondary stage, ie in another pressure sorter 14 be guided, so here again a turbine 6 recover the mechanical power generated by the pressure reduction.

In the 2 illustrated turbine 6 is from a canal wall 24 formed, through which the pulp suspension S flows.

In the channel of the turbine 6 is a generator 7 housed, whose rotatable shaft 21 extends parallel to and against the flow direction of the pulp suspension S.

On the wave 21 can be multiple or but like here only one impeller 22 with attached rotor blades 23 be stored. The rotor blades 23 are inclined to the flow direction and thus cause a rotation of the shaft 21 , Depending on your needs, the rotor blades 23 be realized straight or curved, stiff or adjustable.

Because that's essentially from the rotor blades 23 formed impeller 22 parallel to the shaft 21 is traversed by the pulp suspension S, called this turbine 6 as axial turbine.

For simplicity, here are only a few rotor blades 23 shown. However, in order to produce any additional pressure pulses in the flowing pulp suspension S, the impeller should 22 as much as possible, at least more than 8 rotor blades 23 have.

Furthermore, the generator 7 designed as an asynchronous generator. This contributes because of the relatively constant speed, as already described, in turn to improve the hydraulic stability.

Even with a blockage of the impeller 22 take the turbine 5 . 6 still mechanical power and thus reduces the pressure. The mechanical power is converted in this case into heat and sound.

In contrast, there is the generator 7 in the execution according to 3 outside of the flowed through by the pulp suspension S channel. For this purpose, the rotating shaft 21 from the wheel 22 through the canal wall 24 to the generator 7 guided. To make this possible, the channel runs in the area of the shaft 21 curved.

The generator is an example 7 in the flow direction behind the impeller 22 , Furthermore, in 3 indicated that the channel cross section in the direction of the impeller 22 diminished and then increased again.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102007001848 [0005]

Claims (7)

Arrangement for reducing the pressure during the transport of a pulp suspension (S) by means of a turbine ( 5 . 6 ), which flows through at least one of the pulp suspension (S) and on a rotatable shaft ( 21 ) stored impeller ( 22 ), characterized in that the turbine ( 5 . 6 ) is designed as an axial turbine, wherein the impeller ( 22 ) parallel to the shaft ( 21 ) is flowed through. Arrangement according to claim 1, characterized in that the impeller ( 22 ) at least eight, preferably at least ten rotor blades ( 23 ) owns. Arrangement according to claim 1 or 2, characterized in that the impeller ( 22 ) at least 12, preferably at least 14 rotor blades ( 23 ) owns. Arrangement according to one of the preceding claims, characterized in that the shaft ( 21 ) with a generator ( 7 ), preferably coupled to an asynchronous generator. Arrangement according to one of the preceding claims, characterized in that the pulp suspension (S) from a headbox ( 1 ) a machine for producing a paper, board, tissue or another fibrous web to the turbine ( 5 ) is derived. Arrangement according to one of claims 1 to 4, characterized in that the pulp suspension (S) in the form of the reject of a Drucksortierers ( 12 ) to the turbine ( 6 ). Arrangement according to one of the preceding claims, characterized in that the turbine ( 5 . 6 ) is arranged in the field of preparation of the pulp suspension (S) or in the constant part of a machine for producing a paper, board, tissue or another fibrous web.