EP0633998A1

EP0633998A1 - Method and device for percussive cleaning of objects.

Info

Publication number: EP0633998A1
Application number: EP94907510A
Authority: EP
Inventors: Gustav Thoenes; Ulrich Rottlaender
Original assignee: L&C Steinmueller GmbH
Current assignee: Hitachi Zosen Inova Steinmueller GmbH
Priority date: 1993-02-06
Filing date: 1994-02-07
Publication date: 1995-01-18
Anticipated expiration: 2014-02-07
Also published as: US5597417A; DE4303484C2; EP0633998B1; DE59402491D1; WO1994018518A1; DE4303484A1

Abstract

Method and device for percussive cleaning of objects (1) arranged in a zone subjected to a processing pressure, in which an elongate percussive element (6) is held under and against the object to be cleaned, and percussive energy is applied by means of an accelerated elongate striker (9, 10). In order to achieve easier balancing of the pressure, at least during the acceleration of the striker, the two ends of the latter are maintained at the same pressure, which essentially corresponds to the pressure in the process zone.

Description

description

Method and device for tapping objects

The invention relates to a method and a device of the type mentioned in the preambles of claim 1 and claim 4, respectively.

Such a procedure and such a device are known from DE-PS 31 27 734. The plunger referred to there as the transmission element is provided with an equalizing channel connecting the space under process pressure and the pressure space accommodating a compression spring. The plunger is also provided with a ring collar. Instead of the pressure compensation channel, the compensation space receiving the spring can be connected to an externally operated gas pressure compensation device. In both embodiments of the known knocking device, the pressure equalization takes place in the area of the tappet, so that the tappet must have a relatively complicated design.

In the embodiment with a compensating channel to the space under process pressure, there is a risk that, in the presence of dust-containing gases in the process space, contaminants will be introduced into the spring receiving space. In both embodiments, the free space delimited by one end of the knocking element and by the percussion drive is connected to the atmosphere. The striking element protrudes on one side from the mechanically, pneumatically or hydraulically operated impact device.

It is therefore the object of the present invention to specify a method of the type mentioned above, in which the pressure equalization takes place in a simple manner.

This object is achieved in that, at least during the acceleration of the striking element, the two ends of the striking element are kept under one and the same pressure, which essentially corresponds to the pressure in the process space.

In this way, the required pressure equalization is no longer carried out in the area of the knocking element, but in the area of the mechanically, pneumatically or hydraulically operated impact device, so that no contamination is introduced into the spring chamber via a free equalization channel, which could very quickly lead to malfunctions; a simpler design of the tapping element is also possible. The tapping element can be held under spring elastic prestress by at least one spring or by pneumatic action.

Further subclaims are directed to advantageous refinements of the method.

The invention is also directed to a tapping device for the tapping cleaning of objects arranged in a pressurized process space, with a housing, an elongated tapping element which engages through the wall of the process space and is acted upon by a pretensioning device and is guided in the housing in a sealed manner with a percussion drive including an elongated percussion element aligned with the tapping element, one end of the tapping element and the associated end of the Percussion element protrude into a Freiravun of the housing such that when the percussion drive is at rest, the two ends are at a distance which is dependent on the available percussion energy.

This device is according to the invention characterized in that the knocking element is essentially straight cylindrical and that the end of the impact element which is outstanding from the percussion drive is not surrounded by a compensating space which is connected to the free space in the housing and is connected to an essentially the Process pressure corresponding pressure is applied.

The connection of the free space to the compensation space can be achieved via a connecting line located outside the housing or through at least one compensation channel which is led through the impact element.

When the tapping element is preferably acted upon by a spring, the spring is arranged in the free space, so that the free space serves both to accommodate the spring and to provide the acceleration path required for actuating the device.

Furthermore, it is provided that, viewed in the knocking direction, an annular space which can be acted upon by a sealing gas brought up through the housing is provided behind a seal assigned to the spring-loaded end of the knocking element. The barrier gas can be the same gas, e.g. Nitrogen, as it is used to act on the free space and the compensation space.

This sealing gas can be held in the annular space by a further seal arranged behind the annular space as seen in the knocking direction and / or can flow out through a gas-permeable filter in the direction of the knocking end of the knocking element. Furthermore, it is expedient that the housing at its end facing the object is provided with a guide collar surrounding the knocking element at a distance, the free end of which guides the knocking element still at a distance from the wall delimiting the process space.

The free space and the compensation space are preferably subjected to a lower pressure than the annular space. However, it is also possible to apply the same pressure to the free space, compensation space and annular space if this is somewhat greater than the process pressure. In this connection it should be pointed out that the claims and the description speak of the fact that the compensating pressure which acts on the striking element should essentially correspond to the process pressure. This means that the compensating pressure should not deviate to a large extent from the process pressure, since otherwise the striking element, which is held operationally under the influence of the spring on the object to be cleaned, is subjected to an additional force.

The invention will now be explained in more detail with reference to the accompanying figures. Show it

FIG. 1 shows a section through the invention

Device in which the compensating pressure differs from the pressure of the sealing gas

FIG. 2 a device in which equalizing pressure is equal to the barrier pressure,

FIG. 3 an embodiment comparable to FIG. 1 and 2, whereby, however, the pressure equalization between the equalizing space and the free space does not take place through an external equalizing line, but through an equalizing channel in the impact element, and the end position of the impact element at activated percussion drive can be detected by a position sensor and

FIG. 4 is a partial representation of the arrangement according to FIG. 3 with a tapping element deformed at its tapping end and the percussion element in the striking position.

In FIG. 1 schematically shows, as the object to be cleaned, a heating surface 1 constructed from pipes, which is arranged in the pressure vessel 2 of a coal gasification plant. The heating surface is flowed at least from the outside by dust-laden gas G.

On the wall of the pressure vessel 2, a nozzle 3 with mounting flange 3a is provided for fastening the knocking device 4. The knocking device 4 has a housing 5 with a mounting flange 5a, via which it is screwed to the connecting piece. An essentially straight-cylindrical tapping element 6 is mounted in the housing 5 so as to be axially displaceable. The conically tapered knocking end 6a rests on the heating surface 1 under the action of a compression spring 7, which is supported on the other end 6b of the knocking element on the one hand and on a housing-side step 5a. The end 6b projects into a free space 8 provided in the housing, which also receives the spring.

With the housing 5, a striking device 9 is detachably connected, which in FIG. 1 is designed as a double-acting pneumatic piston cylinder drive. The piston rod 10 protrudes from the cylinder 11 with its two ends 10a and 10b. Knocking element 6 and piston rod 10 are aligned with one another and lie in the same axis. The end 10a of the piston rod 10 also projects into the free space 8. The other end 10b of the piston rod is surrounded by a pressure compensation housing 12 which delimits a compensation chamber 13. The free space 8 and the compensation space 13 are connected to one another via a line 14 connected to each other, which in turn is connected to a pressure source 16 via a pressure control valve 15, preferably ^ source.

A channel 17 is provided in the housing 5, which extends to an annular space 18 formed in the guide section 5c of the housing and is also connected to the pressure source 16 via a control valve 15 '. On the section of the tapping element 6 assigned to the end 6b, a multi-part seal 19 is provided in addition to the annular space 18. On the other side of the annular space 18, seen in the knock direction, a compact seal 20 and then a metal mesh ring 21 acting as a filter are provided. The sealing effect of the seals 19 and 20 is set so that the gas supplied via the channel 17 cannot flow out via the seal 19, but can specifically flow out via the components 20 and 21 into the space under process pressure P2.

The housing 5 is provided at its end facing the heating surface with a guide collar 5d which surrounds the tapping element 6 at a distance and at the free end of which a ring component 22 which surrounds the tapping element and guides it is arranged. To control the control valves 15 and 15 ', a control device 23 is provided, to which a control signal derived from the process pressure i ?? s is supplied via a measuring device 25. In the embodiment according to FIG. 1, the valve 15 is regulated so that a pressure corresponding to the process pressure P ₂ is set in the free space 8 and in the compensation space 13. The contact force of the knocking element 6 on the heating surface 1 is then essentially determined solely by the force of the spring 7. When the piston accelerates along the path from its in FIG. 1 shown rest position until it strikes the end face of the end 6b, a pressure equalization takes place between the rooms 8 and 13 via the line 14. The pressure prevailing in the annular space 18 is somewhat reduced by the control device 23 according to a pressure p via the control valve 15 ' set higher than the process pressure P ₂ .

In summary: P ₂ = Pg = and P ₁₈ slightly larger than P ₂ .

In the case of FIG. 2 embodiment shown, the channel 17 is connected directly to the connecting line 14, so that the control device 23 controls only the control valve 15. In this case the following applies: Pg = P ₁₃ = P ₁₈ and P ₂ slightly smaller than Pg.

In the embodiment according to FIG. 2 could be dispensed with the spring 7, because due to the Δ p to the pressure P _2, the knocking element 6 is brought into contact with the heating surface 1. Because of possible pressure fluctuations in the process space, however, a spring 7 should be present.

From the description of the figures it can be seen that the required pressure equalization to the tank pressure P2 is not achieved by a special application and design of the knocking element, but by a simple design and operation of the percussion drive. Through the targeted application of a sealing gas in the area of the tappet via the annular space 18, a directed leakage in the direction of the interior of the pressure vessel 2 is achieved, so that the entire knocking space is rendered inert. This has a corrosion-inhibiting effect. Furthermore, the seal provided for dust filtering is kept free by the leakage flow.

When in the FIG. 3 and 4 shown embodiment, the pressure equalization between the free space 8 in the housing 5 does not take place via the in the FIG. 1 and 2 branching off from the outlet of the valve 15 and leading to the pressure equalization space 13 of the line 14, but via a pressure equalization channel which leads from the end 10a of the piston rod 10 to the end 10b of the piston rod. This pressure compensation duct consists of radial bores 10d and the duct 10e which preferably extends axially in the middle through the piston rod 10. In FIG. 3, the piston rod 10 with its piston 10c is displaced into its right end position by the spring 7. When the piston-cylinder drive is activated, the piston rod is pressed against the knock element 6 in FIG. 3 accelerated to the left.

As shown in FIG. 4 can be seen in the course of operation as a result of frequent tapping movements, the working end of the tapping element 6 deform, d. H. the end position of the right end 10b shifts to FIG. 3 and 4 to the left accordingly.

A pressure transducer 24 is arranged on the pressure compensation housing 12 and can detect the shortening of the knocking element 6 by detecting the displacement of the end position of the piston rod of the actuated piston cylinder drive. This is shown schematically in FIG. 4 shown. Inductive or capacitive proximity sensors arranged from outside the housing 12 are suitable as measuring sensors. It is also conceivable to provide photoelectric arrangements within the pressure space 13. It is also possible to arrange a mechanical-electrical measuring pin as a limit switch within the pressure chamber.

If the output signal of the proximity initiator indicates that there is a deformation of the knocking element that is no longer acceptable for the knocking operation, the knocking element must be replaced.

(3 sheets of drawings)

Claims

A method for tapping cleaning of objects arranged in a process pressure space, in which an elongated tapping element is held in contact with the object to be cleaned and tapping energy is applied to the tapping element by means of an accelerated elongated striking element, characterized in that at least during acceleration of the striking element, the two ends of the striking element are kept under one and the same pressure, which essentially corresponds to the pressure in the process space.

A method according to claim 1, so that the pressure in the process space is detected and the pressure acting on the two ends of the striking element is set as a function of the measured process pressure.

A method according to claim 1 or 2, characterized in that, viewed in the knocking direction, a sealing gas is applied at a distance from the end of the knocking element acted upon by the impact element such that it can flow away at most in the direction of the knocking end of the knocking element.

4. The method according to at least one of claims 1-3, d a d u r c h g e k e n n z e i c h n e t that the knocking element is held under spring elastic bias.

5.Device for tapping cleaning of objects arranged in a process space under a process pressure with a housing, a gripping through the wall of the process space and under the action of a pretensioning device against the object and sealingly guided in the housing and guided by a percussion drive including one elongated striking element aligned with the knocking element, one end of the knocking element and the associated end of the striking element projecting into a free space of the housing in such a way that when the striking drive is at rest, the two ends are at a distance dependent on the available impact energy, characterized in that the knocking element ( 6) is essentially straight cylindrical and that the end (10b) of the percussion element (10) projecting from the percussion drive which is not facing the tapping element (6) is surrounded by a compensation space (13), de r with the free space (8) in the housing (5) in connection (14; 10 d, e) and a pressure (P13 _. Pg) corresponding to the process pressure (P) is applied to it.

6. The device according to claim 5, d a d u r c h g e k e n n z e i c h n e t that when the knocking element (6) is acted upon by a spring (7) this is arranged in the free space (8).

7. The device according to claim 5 or 6, characterized in that seen in the knocking direction behind one of the spring-loaded end (6b) of the knocking element associated seal (19) with an annular space (18) which can be acted upon by the housing (5) is provided.

8. The device according to at least one of claims 5-7, that a further seal (20) and / or a gas-permeable filter (21) are arranged behind the annular space (18) when viewed in the knocking direction.

9. The device according to at least one of claims 5-8, characterized in that the housing (5) at its end facing the object (1) is provided with a tapping element (6) surrounding the guide collar (5d) at a free end (22) the tapping element (6) is still guided at a distance from the wall delimiting in the process space (2).

10. The device according to at least one of claims 5-9, d a d u r c h g e k e n n z e i c h n e t that the free space (8) and the compensation space (13) with a lower pressure (^ P) than the annular space (18) are applied.

11. The device according to at least one of claims 5-9, characterized in that the free space (8) and the compensation space (13) and the annular space (18) are acted upon with the same pressure that is greater (AP) ^a *** - ^s the process pressure .

12. The device according to at least one of claims 5-11, d a d u r c h g e k e n n z e i c h n e t that in the compensation space (13) protruding end (10 b) of the striking element (10) one

Position detection device (25) is assigned such that changes in the position of the striking element (10) in its striking end position can be detected.