EP2492335A1 - Method and device for homogenising a mixture of solid fuel in a liquid - Google Patents

Abstract

The method comprises premixing a feed mixture, producing the feed mixture comprising a solid fuel in a liquid towards a cross-sectional constriction (12), increasing a pressure of the feed mixture in production of the feed mixture towards the cross-sectional constriction, releasing the feed mixture in a passage through the cross-sectional constriction under formation of an initial mixture. Materials comprise a hydrocarbon, a solvent, which forms a water-azeotropic mixture, and water. The feed mixture has an input particle size distribution. The method comprises premixing a feed mixture, producing the feed mixture comprising a solid fuel in a liquid towards a cross-sectional constriction (12), increasing a pressure of the feed mixture in production of the feed mixture towards the cross-sectional constriction, releasing the feed mixture in a passage through the cross-sectional constriction under formation of an initial mixture. Materials comprise a hydrocarbon, a solvent, which forms a water-azeotropic mixture, and water. The feed mixture has an input particle size distribution, and the initial mixture has an output particle size distribution extending in factors that differ an expected value of the particle size distribution, a layer of a maximum value of the grain size distribution, and a breadth with half-height of the grain size distribution. A flow direction of the mixture changes at 30[deg] . Parameters are adjustable with a size of the cross-sectional constriction, and the pressure of the feed mixture, which is achieved in the increasing step. The cross-sectional constriction is formed by a poppet valve. The feed mixture has a solid content of >= 50 wt.%. An independent claim is included for a device for homogenizing a mixture of solid fuel in a liquid.

Description

The subject of the present invention is a method and an apparatus for homogenizing a mixture of solid fuel in a liquid. The process is particularly preferably used in the homogenization and dispersion of carbon particles in hydrocarbons, such as, for example, a light fuel oil.

Liquid hydrocarbons such as light fuel oil are widely used in combustion processes. For example, light fuel oil is often used in homes for heating and heat supply in industry and commerce. Even in the power plant area, light fuel oil is used as ignition or support fuel. There is a need to change the fuels, especially with regard to cost aspects. For example, coal, especially lignite, mixed with fuel oil could be used as fuel for heat production in industry and commerce. However, in this combination it is necessary to prevent segregation of solid fuel and fuel oil. Such could lead to damage to the fire equipment or even not possible combustion.

From the DE 10 2007 034 253 A1 For example, a method is known in which a carbonaceous solid is dispersed in a liquid by exposing it to an ultrasonic field. Whether this method can be used on an industrial scale is questionable. The necessary energy expenditure is considerable in this process.

The object of the present invention is to at least partially overcome the disadvantages known from the prior art and in particular to provide a method and a device, with which a mixture of a solid fuel in a liquid can be produced, which achieves a high homogeneity with respect to the distribution of the solid particles in the liquid and with respect to the grain size distribution of the solid fuel and with which it is possible to use a non-decombining mixture of solid fuel in To produce liquids.

These objects are achieved by the features of the independent claims. The respective dependent claims are directed to advantageous developments.

The features listed individually in the claims can be combined with each other in any technologically meaningful manner and can be supplemented by explanatory facts from the description, with further embodiments of the invention being shown.

1. a. Förderung einer Eingangsmischung umfassend Festbrennstoff in einer Flüssigkeit in Richtung mindestens einer Querschnittsverengung;
2. b. Erhöhung des Drucks der Eingangsmischung bei Förderung der Eingangsmischung in Richtung der mindestens einen Querschnittsverengung; und
3. c. Entspannung der Eingangsmischung beim Durchtreten durch die mindestens eine Querschnittsverengung unter Bildung einer Ausgangsmischung.

The present invention relates to a process for homogenizing a mixture of solid fuel in a liquid, characterized by the following steps:

1. a. Conveying an input mixture comprising solid fuel in a liquid in the direction of at least one cross-sectional constriction;
2. b. Increasing the pressure of the input mixture while conveying the input mixture in the direction of the at least one cross-sectional constriction; and
3. c. Relaxation of the input mixture when passing through the at least one cross-sectional constriction to form a starting mixture.

The input mixture comprises solid fuel particles dispersed in a liquid. By the method according to the invention it is possible to finely disperse these fuel particles, wherein the middle Particle diameter is significantly reduced and the distribution of solid fuel particles in the liquid is made uniform. In this case, preference is given to a process procedure in which, in process step 1.c, the pressure of the mixture is reduced by a factor of up to 200, particularly preferably up to 400 and in particular even up to 500. This means that the quotient of the pressure of the inlet mixture before the cross-sectional constriction to the pressure of the starting mixture downstream of the cross-sectional constriction is in the range of 150 and 500. Preferred is a process control with a pressure of 2000 bar absolute upstream of the cross-sectional constriction and from 5 to 10 bar absolute downstream of the cross-sectional constriction. Preferably, the cross-sectional constriction is designed so that the flow velocity in the gap is more than 100 m / s [meters per second].

The sudden relaxation accelerates the mixture as it passes through the cross-sectional constriction, it comes to collisions of the solid fuel particles together and on the walls or boundaries in the delivery area. By this, the solid fuel particles are crushed. The term cross-sectional constriction is understood to mean that the mixture before it enters the cross-sectional constriction can flow through a cross-section through which is larger than the cross-section through which the cross-sectional constriction can flow. In particular, the cross-sectional constriction is understood as meaning a gap through which the mixture must flow. Preferred is an embodiment in which the cross-sectional constriction has a gap of a gap height of less than 1 mm [millimeter], preferably less than 0.5 mm, in particular less than 0.2 mm. Preference is given to a process control in which the freely flow-through cross section upstream of the cross-sectional constriction, the size of the cross-sectional constriction, ie the freely flow-through cross-section of the cross-sectional constriction and the freely flowable cross-section downstream of the cross-sectional constriction are chosen so that a pressure drop of about 200 to 400 bar absolute upstream of the cross-sectional constriction to 1 to 6 bar absolute downstream of the cross-sectional constriction takes place. Preferably, the cross-sectional constriction is designed so that the flow of the mixture is directed during or after passage of the cross-sectional constriction against at least one baffle.

Preferably, the flow paths of the mixture are designed so that the mixture, after flowing through the cross-sectional constriction, strikes a baffle element, which further leads to a reduction of the particle diameter. At the same time, the turbulent flow which arises when passing through the cross-sectional constriction breaks up any laminar or pseudo-laminar flow profiles that may be present, mixing the mixture, thereby equalizing the particle distribution in the liquid and equalizing the particle size distribution.

A solid fuel is understood in particular to mean a carbonaceous solid fuel. The solid fuel is preferably coal, such as lignite, hard coal or charcoal, in particular lignite, preferably in the form of lignite dust or lignite coke. Other possible solid fuels are bitumen, asphalt, tar, peat, xylitol and lignite coke.

1. a. mindestens einen Kohlenwasserstoff;
2. b. ein Lösungsmittel, welches mit Wasser ein azeotropes Gemisch bildet; und
3. c. Wasser.

According to an advantageous embodiment of the method according to the invention, the liquid comprises at least one of the following substances:

1. a. at least one hydrocarbon;
2. b. a solvent which forms an azeotropic mixture with water; and
3. c. Water.

By a hydrocarbon is meant compounds comprising carbon and hydrogen, especially carbon and hydrogen exist. Advantageously, the inventive method in a liquid comprising a plurality of hydrocarbons of different chain lengths. Such liquids occur regularly at certain distillation stages in petroleum refining. The process according to the invention for homogenizing solid fuel, in particular brown coal in so-called light fuel oil, has proved to be particularly advantageous. Preferably, this is light fuel oil according to the German industrial standard DIN 51603. This may include one or more additives in addition to hydrocarbons.

A solvent which forms an azeotropic mixture with water is, for example, toluene. By an azeotropic mixture is meant a mixture which can not be separated by ordinary distillation. Solvents which form an azeotropic mixture with water can be used for dewatering coal, as these water bound in the coal can be dissolved out. This is equally possible with other solid fuels. An example of such a solvent is toluene.

Furthermore, it is possible that the liquid also contains water, preferably water. By the homogenization of solid fuel particles, in particular of carbon particles in water, foreign components can be dissolved out of the coal in an advantageous manner, which are harmful in the further process for secondary products. For example, alkali metals such as sodium, which are soluble in water, can be dissolved out of the solid fuel particles. Since the inventive method causes an increase in the total surface area of the solid fuel particles by reducing the diameter and a more uniform distribution of the solid fuel particles in the water, the amount of extraneous foreign matter dissolved significantly improved. Thus, the inventive method as a precursor for a demineralization can be used, as described for example in DE 10 2004 038 235 A1.

1. a. dem Erwartungswert der Korngrößenverteilung;
2. b. der Lage des Maximalwerts der Korngrößenverteilung; und
3. c. der Breite bei halber Höhe der Korngrößenverteilung.

According to a further advantageous embodiment of the method according to the invention, the input mixture has an input particle size distribution and the output mixture has an output particle size distribution which differs in at least one of the following factors:

1. a. the expected value of the particle size distribution;
2. b. the location of the maximum value of the particle size distribution; and
3. c. the width at half height of the particle size distribution.

The grain size distribution is the probability distribution that indicates the probability of the occurrence of a specific grain size. The expectation value is the value of the grain size, which usually results from frequent sampling. The position of the maximum value of the particle size distribution is understood to be that particle size for which the highest probability is present. The width at half grain size distribution is understood to mean the width of the grain size distribution at half the maximum value of the grain size distribution.

According to the method according to the invention, in particular the pressure difference across the cross-sectional constriction, ie the difference of the pressure upstream and downstream of the cross-sectional constriction can be set so that the expected value and / or the position of the maximum value of the grain size distribution shift towards smaller grain sizes, ie the input mixture an expectation and / or has a position of the maximum value of the particle size distribution which is smaller than the corresponding value of the output particle size distribution. In addition, the difference in pressure becomes a downstream position as compared with a position upstream of the cross-sectional constriction the cross-sectional constriction and / or the size of the cross-sectional constriction set so that the width decreases at half the height of the particle size distribution. In this case, preference is given to a process control in which the quotient of the width at half the height of the input particle size distribution to the width at half the height of the output particle size distribution is in the range from 20 to 100, preferably this quotient is at least 10.

According to a further advantageous embodiment of the method according to the invention, in step 1.c the flow direction of the mixture changes at least once by at least 30 °.

It has been shown that it is advantageous to design the flow path which the mixture covers in the method according to the invention in such a way that at least a significant deflection of the flow direction takes place, preferably even two or more changes in the flow direction. Particular preference is given to changes in the flow direction approximately at right angles or more. The corresponding collisions during the deflection result in a further reduction in the particle size of the solid fuel particles and in the formation of turbulent flows, which promote further mixing of the mixture.

Furthermore, sharp changes in the direction of the flow cause a break-up of any laminar or quasi-laminar flows or edge flows. As a result, a further homogenization of the distribution of the particles in the liquid is achieved because turbulent flows are generated, which lead to a mixing of the liquid.

• a. die Größe der mindestens einen Querschnittsverengung; und
• b. der Druck der Eingangsmischung, der in Schritt 1.b erreicht wird.

According to a further advantageous embodiment of the method, at least one of the following parameters is adjustable:

• a. the size of the at least one cross-sectional constriction; and
• b. the pressure of the input mixture, which is reached in step 1.b.

Alternatively or additionally, the pressure increase or the degree of pressure increase in the promotion in step 1.b is adjustable, for example by appropriate selection and control of the funding. By adjusting the size of the cross-sectional constriction and / or the pressure build-up before flowing through the cross-sectional constriction can be adjusted advantageously the particle size distribution of the output particle size distribution of the starting mixture. That is, by adjusting the size of the cross-sectional constriction and / or the pressure, the average grain size and / or the width of the grain size distribution of the starting mixture can be variably adjusted. Furthermore, it is thus possible to achieve a distribution of the solid fuel particles in the liquid that corresponds to a specification. It is thus also the homogeneity of the distribution of the particles in the liquid adjustable.

According to a further preferred embodiment of the method, the cross-sectional constriction is formed by at least one seat valve.

The use of a poppet valve allows, by adjusting the gap size of the valve opening, so the gap between the valve body and the valve seat, a variation of the size of the cross-sectional constriction. This can be achieved by appropriate measures such as a change in the bias of a spring, with which the valve body is pressed against the valve seat or under variation of a back pressure, with which the valve body is pressed against the valve seat. By changing these parameters, the size of the cross-sectional constriction can be set to predefinable values.

According to a further advantageous embodiment of the method according to the invention, the solids content of the input mixture is 50 wt .-% and more.

In particular, the solid fuel is coal, such as lignite or hard coal, and particularly preferably lignite. The Applicant has found that despite the abrasive properties of the coal and the relative hardness of the solid fuel particles with the process of the invention, a good reduction in grain size and good homogenization have been achieved. The solids content of the initial mixture and thus also of the starting mixture is preferably in the range from 50% by weight to 80% by weight, particularly preferably in the range from 50% by weight to 70% by weight.

According to a further advantageous embodiment of the method according to the invention, the input mixture is before or during step 1.a. premixed.

This can be done in particular by a static mixer or a mixer with stirrer. By premixing, it can be achieved that the homogenization of the starting mixture is further improved, as it has been shown that the mixing efficiency as well as the efficiency of the reduction process of the solid fuel particles in the liquid is higher when the input mixture is premixed.

• a. mindestens ein Fördermittel zur Fördern und Erhöhen des Drucks einer Eingangsmischung aus Festbrennstoff in einer Flüssigkeit hin zu mindestens einer Querschnittsverengung; und
• b. Umlenkmittel zum mindestens einmaligen Umlenken der Mischung beim Durchtreten durch die mindestens eine Querschnittsverengung unter Bildung einer Ausgangsmischung.

According to another aspect of the present invention, there is provided an apparatus for homogenizing a mixture of solid fuel in a liquid comprising:

• a. at least one conveying means for conveying and increasing the pressure of an input mixture of solid fuel in a liquid towards at least one cross-sectional constriction; and
• b. Deflection means for deflecting the mixture at least once when passing through the at least one cross-sectional constriction to form a starting mixture.

Under the funding is in particular a pump understood, preferably a piston pump. The use of a piston pump has the advantage over other pumps that the delivery rate of the pump is independent of the pressure. By using appropriate piston pumps, pressures of up to 2,000 bar can be achieved before the cross-sectional constriction. Advantageous are conveying means in which the pressure before the cross-sectional constriction can be increased to 500 bar and more, preferably to 1000 bar and more, and more preferably to 1500 bar and more.

According to an advantageous embodiment of the device according to the invention, the size of the cross-sectional constriction is adjustable by a valve, in particular a seat valve.

By a valve and in particular a poppet valve, it is possible to make the size of the cross-sectional constriction easily adjustable and to keep variable in certain areas. In particular, a seat valve has been found to be preferred, since there is the cross-sectional constriction through the gap, which results in open valve between the valve seat and valve body, which can thus be adjusted by changing the bias or the opening of the poppet valve necessary force.

Fig. 1:

ein Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung im Schnitt;

Fig. 2:

ein Ausführungsbeispiel der vorliegenden Erfindung mit Zusatzaggregaten;

Fig. 3:

einen Teil einer erfindungsgemäßen Vorrichtung zur Illustration des Verfahrensprinzips; und

Fig. 4

eine erläuternde Ansicht der Korngrößenverteilung der Eingangs- und der Ausgangsmischung.

The details and advantages disclosed in the document for the method according to the invention can be transferred to the device according to the invention and applied, and vice versa. In the following, the invention will be explained in more detail with reference to the attached figures, without being limited to the details and exemplary embodiments shown there. They show schematically:

Fig. 1:

an embodiment of a device according to the invention in section;

Fig. 2:

an embodiment of the present invention with additional units;

3:

a part of a device according to the invention for illustrating the method principle; and

Fig. 4

an explanatory view of the grain size distribution of the input and the output mixture.

Fig. 1 schematically shows an embodiment of an apparatus 1 for homogenizing solid fuel in a liquid. The device 1 comprises a conveying means 2, in the present embodiment a piston pump with a piston 3. The piston 3 is linearly movable in a first direction of movement 4 in a guide channel 5. Due to the movement of the piston 3, a positive or negative pressure is generated in a delivery chamber 6, depending on the direction of movement 4. As a result, an input mixture can be conveyed through an inlet 7 into the delivery chamber 6. The input 7 can be reversibly closed by a valve 8. From the delivery chamber 6, the mixture can be conveyed through a delivery chamber outlet 9. Also, the delivery chamber outlet 9 can be reversibly closed by a corresponding valve 10. Thus, by a corresponding movement of the piston 3 in the first direction of movement 4 and a corresponding control of the valves 8, 10, the input mixture from the inlet 7 to the delivery chamber outlet 9 are promoted and thereby put under pressure.

The corresponding streams are indicated by arrows 11. After passing through the delivery chamber outlet 9, the inlet mixture flows toward a cross-sectional constriction 12. This cross-sectional constriction 12 is formed by a seat valve 13, which comprises a valve body 14 and a valve seat 15. In this embodiment Thus, the cross-sectional constriction 12 represents an annular gap whose gap height is preferably less than 1 mm [millimeter], more preferably less than 0.5 mm, in particular less than 0.2 mm. In operation, the cross-sectional constriction 12 is present as an annular gap between the valve body 14 and the valve seat 15. Downstream of the cross-sectional constriction 12, the flow-through cross section widened again for the stream 11, it comes when flowing through the cross-sectional constriction 12 to an acceleration of the material flow 11 and a subsequent slowing down. As it flows through the cross-sectional constriction 12, the material flow 11 follows the flow path 16. This has two changes in the flow direction. As it flows through the flow path 16, the material flow 11 is pressed against baffles 17, which also act as deflection means 38. These are formed, on the one hand, from the side of the valve body 14 facing the flow and, on the other hand, by the regions of the valve outer body 18 lying next to the valve seat 15. After flowing through the flow path 16 of the material flow 11 is conveyed as output mixture from the output 19. The deflection means 38 thus cause a twice deflection of the flow by 90 °.

Fig. 2 1 schematically shows the apparatus 1 for homogenizing a mixture of solid fuel in a liquid in a larger context. Upstream of the device 1, a prefeed pump 20 and a premixer 21 are formed. In the pre-mixer 21 is a premix of solid fuel, such as lignite dust, with the liquid, such as light fuel oil. As a pre-mixer 21, a static mixer or a Zahnkranzdispergator or a mixing vessel with agitator can be used. The prefeed pump 20 conveys the premix as an input mixture from the premixer 21 to the device 1 according to the invention. The prefeed pump 20 may be, for example, a gear pump.

Fig. 3 schematically shows a section of a device 1, at which the operating principle and the process control according to the present invention will be explained in more detail. A mixture 22 of solid fuel particles 25 in a liquid 24 is conveyed from the delivery chamber 6 through the delivery chamber exit 9 in the direction of the cross-sectional constriction 12. As it flows through the cross-sectional constriction 12, the solid fuel particles 23 abut against the baffles 17 and are comminuted with each other there as well as with impacts. The cross-sectional constriction 12 is given by the gap between a valve seat 15 and a valve body 14 of a seat valve 13. By adjusting the valve pressure or the valve force 25, with which the valve body 14 is pressed in the direction of the valve seat 15, the size of the cross-sectional constriction 12 can be adjusted in conjunction with the delivery pressure 26. After flowing through the cross-sectional constriction 12, the mixture 22 has a discharge pressure 27, with which the mixture 22 flows through the outlet 19. As schematically shown, the solid fuel particles 23 have a smaller diameter after flowing through the cross-sectional constriction 12.

Fig. 4 shows schematically the particle size distribution of the mixture. Before passing through the cross-sectional constriction 12, the input particle size distribution 28 is present. After flowing through the cross-sectional constriction 12, the output particle size distribution 29 is present. Shown in each case is the probability P of the occurrence of a grain size d, both in each case given in relative units. The input grain size distribution 28 has a maximum value which is present at a position 31. The output grain size distribution has a maximum value 32 at a position 33. The layer 31 of the maximum value 30 of the input grain size distribution 28 differs from the layer 33 of the maximum value 32 of the input grain size distribution 28. The layer 33 is shifted towards smaller grain sizes compared to the layer 31.

The input grain size distribution 28 has a full width at half height 34 (full with half maximum). This is determined by taking a horizontal cut through the input grain size distribution 28 at half the maximum value 30 and looking at the width of this cut. Similarly, a full width at half height 35 of the output grain size distribution 29 may be formed. The full width at half height 34 of the input particle size distribution 28 is significantly greater than the full width at half height 35 of the output particle size distribution 29. The method according to the invention thus leads to smaller particle sizes of the solid fuel particles 23 and to a narrower output particle size distribution 29. Simultaneously, the formation of turbulent flows as it flows through the cross-sectional constriction 12, the particles are more evenly distributed. The expected value 36 of the input particle size distribution 28 is also at a different point than the expected value 37 of the output particle size distribution 29.

Due to the differences in the properties and the behavior of the individual substances of the solid fuel particles 23 present locally in the solid fuel particle, it can be achieved by a corresponding adjustment of delivery pressure 26, valve force 25 and size of the cross-sectional constriction 12 that only the solid carbon components disperse, while the ash formers are not dispersed in order to be able to separate these in a downstream separation step, for example with a multiphase decanter. Preferably, a process control is selected in which the resulting starting mixture is stable for a long time, that is not segregated. For this purpose, preference is given to choosing liquids 24 which have the same density as the solid fuel particles 23, whereby the use of additives for changing the density of the liquid 24 is possible and according to the invention. Preferably, such an additive is chosen so that the density of the liquid 24 is as close as possible to the density of the solid fuel particles 23.

The inventive method and the device 1 advantageously allow the formation of a homogeneously mixed starting mixture of solid fuel particles 23 in a liquid 24. This can be designed so that there is substantially no density difference between the solid fuel particles 23 and the liquid 24, in particular by Adding additives to the liquid 24. Thus, a non-segregating dispersion of solid fuel particles 23 in liquid 24 can be generated, which can be used without hesitation, for example, as a fuel, without the fireplaces compared to the combustion of pure liquid 24 must be designed significantly different.

LIST OF REFERENCE NUMBERS

1

Apparatus for homogenizing a mixture of solid fuel in a liquid

2

funding

3

piston

4

first direction of movement

5

guide channel

6

delivery chamber

7

entrance

8th

Valve

9

Conveying chamber output

10

Valve

11

material flow

12

Cross-sectional narrowing

13

poppet valve

14

valve body

15

valve seat

16

flow path

17

baffle

18

Valve outer body

19

output

20

prefeed

21

premixer

22

mixture

23

Solid fuel particles

24

liquid

25

valve power

26

delivery pressure

27

outflow pressure

28

Input grain size distribution

29

Initial particle size distribution

30

maximum value

31

location

32

maximum value

33

location

34

full width at half height

3 5

full width at half height

36

expected value

37

expected value

38

deflecting

Claims (10)

A method of homogenizing a mixture (22) of solid fuel (23) in a liquid (24) characterized by the following steps: a. Conveying an input mixture comprising solid fuel (23) in a liquid (24) in the direction of at least one cross-sectional constriction (12); b. Increasing the pressure of the inlet mixture while conveying the inlet mixture in the direction of the at least one cross-sectional constriction (12); and c. Relaxation of the input mixture when passing through the at least one cross-sectional constriction (12) to form a starting mixture. The method of claim 1, wherein the liquid (24) comprises at least one of the following: a. at least one hydrocarbon; b. a solvent which forms an azeotropic mixture with water; and c. Water. The method of any one of the preceding claims, wherein the input mixture has an input particle size distribution (28) and the output mixture has an output particle size distribution (29) that differs in at least one of the following factors: a. the expected value (36, 37) of the particle size distribution; b. the position (31, 33) of the maximum value (30, 32) of the particle size distribution; and c. the width at half height (34, 35) of the particle size distribution. Method according to one of the preceding claims, wherein in step 1.c the flow direction of the mixture changes at least once by at least 30 °. Method according to one of the preceding claims, in which at least one of the following parameters is adjustable: a. the size of the at least one cross-sectional constriction (12); and b. the pressure of the input mixture, which is reached in step 1.b. Method according to Claim 5, in which the cross-sectional constriction (12) is formed by at least one seat valve (13). A process according to any one of the preceding claims, wherein the solids content of the input mixture is 50% by weight or more. Method according to one of the preceding claims, wherein the input mixture is premixed before or during step 1.a. Apparatus (1) for homogenizing a mixture of solid fuel in a liquid, comprising: a. at least one conveying means (2) for conveying and increasing the pressure of an input mixture of solid fuel (23) in a liquid (24) towards at least one cross-sectional constriction (12); and b. Deflection means (38) for at least one time redirecting the mixture as it passes through the at least one cross-sectional constriction to form a starting mixture. Apparatus according to claim 9, wherein the size of the cross-sectional constriction (12) by a valve, in particular a seat valve (13) is adjustable.

Images