DE102008007976A1 - Device to neutralize acid combustion condensates, has common box-shaped container containing neutralizing agent, a sensor with transmitter and receiver for controlling a condensate pump, vibration exciter, and injection devices - Google Patents

Abstract

The device comprises a common box-shaped container (1), which contains a neutralizing agent, has an inlet (9) and an outlet (10) for an acid combustion condensate and is lockable by a lid (7), a sensor intended for controlling a condensate pump and having a transmitter and a receiver, a vibration exciter attached in and/or at the container, and devices for injecting air or gas. The neutralizing agent is incorporated into the container in the form of wall surfaces. The container is sub-divided into neutralizing chamber sections sequentially separated from each other by a separating wall. The device comprises a common box-shaped container (1), which contains a neutralizing agent, has an inlet (9) and an outlet (10) for an acid combustion condensate and is lockable by a lid (7), a sensor intended for controlling a condensate pump and having a transmitter and a receiver, a vibration exciter attached in and/or at the container, and devices for injecting air or gas. The neutralizing agent is incorporated into the container in the form of wall surfaces. The container is sub-divided into neutralizing chamber sections sequentially separated from each other by a separating wall with a wall surface and/or surface containing the neutralizing agent, so that the condensate partially flows through the container in a meander-like manner. The condensate flows along at the wall surface. The neutralizing chamber sections are limited by longitudinal walls, which run parallel to each other and to the flow direction of the condensate, lie at a distance from one another, extend themselves between the oppositely-lying sidewalls of the container and have same height as the sidewalls, and by transverse walls, which are aligned vertical to the flow direction of the condensate and extend themselves between the longitudinal walls. The transverse walls forming a first group are arranged above the sieve bottoms and their upper edges lie below the upper edges of the longitudinal walls. The transverse walls forming a second group extend themselves up to a height from the base of the chamber section over the sieve bottoms, where the height lies below the height of the transverse wall of the first group. The transverse walls are alternatively arranged to each other. The longitudinal walls are provided with openings and/or recesses at the container sidewall or the end turned to the container sidewall at the upper side and at the lower side. The openings and/or recesses present at the upper side of the longitudinal walls form overflows, which lie in same height as the upper edges of the transverse walls of the first group. The chamber sections are combined to a rectangular block in a module-like manner. The rectangular block has two oppositely-lying sidewalls. A condensate outlet chamber having the condensate outlet follows to the last chamber section in the flow direction. The condensate outlet chamber is separated from the last chamber section by a partition wall, which has opening connected to the chamber section with the condensate outlet chamber in its upper region, where the opening is in the form of overflow weirs. A liquid inlet flows into a solid particle-settling chamber. A filter chamber (13) receiving an activated charcoal filter follows to the solid particle-settling chamber and is upstream to the chamber sections. A separating wall is arranged between the settling chamber and the filter chamber with an overflow weir present at its upper side. A separating wall is upstream to the first chamber section with an overflow present at the upper side of the separating wall, where a channel follows to the separating wall and guides to a liquid inlet opening lying below the sieve bottoms of the first chamber section. The device has a chamber upstream to the condensate outlet, where the chamber is sub-divided into an upper chamber section forming the condensate outlet chamber for receiving the wet-running rotor including pump wheels of a centrifugal pump and into a lower chamber section for receiving the stator of the centrifugal pump. A separator is present between the upper and the lower chamber sections and has a bottom section, which lies above the level of the container base. The bottom section has a bearing element on its upper side for bearing the rotor including the pump wheels and is provided with a recess for receiving and bearing the wet-running rotor and the pump wheels. The upper chamber section has a holder for fastening a floating device equipped with a transmitter. The lower chamber has an upwardly directed chamber extension. The stator in the upper chamber section and the rotor in the lower chamber section are attached to the condensate pump. A conveying pipe of the condensate pump is connected to the condensate outlet. The condensate pump is a ball rotor pump, whose wet-current part is attached in the upper chamber section consisting of rotor and pump wheels during the stator presents itself in the area of the lower chamber section. The transmitter is fixed in the area of the upper chamber section and is fastened at a floater movable along a guide. The receiver is fixed in the area of the lower chamber section. The wall surfaces containing the neutralizing agent are formed by plates from neutralizing agent and are formed by insert bodies of any shape. The wall surfaces containing the neutralizing agent are applied as coating material on base bodies and/or base plates, have a roughened and/or structured surface and are exchangeable inserted into the container. The coating material is present in the form of foils and is sprayed. Inserts mountable into the container have plate-shaped or column-shaped structures with surfaces, which contain the neutralizing agent. The wall surfaces include lower, neutralizing agent-free wall surface sections. The insert bodies have column shape and consist of neutralizing agent and/or are coated with the neutralizing agent over a part of its height. The separating walls are provided with vertical slots for replacing transverse walls by the inserts.

Description

The The invention relates to a device for the neutralization of acidic Combustion condensates consisting of a neutralizing agent containing Container having an inlet and a drain for has the condensate.

The Cool exhaust gases from gas or oil powered heating systems Turn off in the boiler and in the chimney. By the cooling creates a condensate in the acid and combustion residues are included. Before these combustion condensates z. B. in one Channel connection must be routed they are cleaned and neutralized.

At one in the EP 0 174 349 B1 As described apparatus, the Kondensatzulauf takes place laterally through the bottom in a cylindrical neutralization chamber to flow through in the neutralization chamber befindliches granular neutralizing agent from bottom to top. The operational capability of the device is very quickly called into question when blockages occur in the region of the neutralization chamber, for example as a result of sludge formation, flocculations or the like. The same applies to a neutralizing agent receiving, horizontal neutralization chamber whose end walls have the inlets and outflows for the condensate.

One in the DE 35 40 164 A1 described apparatus for neutralizing acidic condensates from exhaust gases of heating systems contains a closed container by means of a lid, in which a neutralization chamber is used to receive a granular neutralizing agent. The bottom of this neutralization chamber is provided with screen openings, such that at the top of the container incoming combustion condensate after passing through the neutralizing agent from top to bottom through the sieve bottom and can flow through a arranged in the region of the container bottom drain.

One in the DE 93 11 083 U1 treated neutralization device consists of several successively connected neutralization tanks, which are provided in the lower part, each with a sieve bottom for storage of granular neutralizing agent and flow through the condensate meandering, first from top to bottom in the first container, then from bottom to top in The following container, then again from top to bottom in the following container, etc. .. Also in this neutralization occur on the above-described Verschlammungs- and constipation problems, which also lead to the neutralizing agent used only insufficient or in certain parts in the neutralization of the Condensate can not be effective at all.

In Dependence on the chemical compositions of the combustion condensate and the granular neutralizing agent consists, as already mentioned, the risk of flocculation with the time can cause the granular Neutralizing agent cakes into a relatively compact cake, so that the condensate may no longer be trouble-free can flow through the device. To this disadvantage to remedy, devices have already been proposed in those above the bottom of the container at a distance a sieve tray on which the granular neutralizing agent stores, is arranged, and that in the container walls are used, the meandering flow of the Condensate caused by the container. The walls are inserted in the container so that clogged up Form zones or areas immediate bypass flows which allows considerably larger Operating times can be achieved than at the above described known neutralization devices.

Of the Invention is based on the object, one also opposite the last described, to the same assignee and inventor receding neutralization device improved device to accomplish.

to Solution to this problem is proposed according to the invention, that the neutralizing agent in the container in the form is absorbed by wall surfaces, where the condensate preferably meandering in the horizontal direction flows past. Emerging flocculation can then settle on the bottom of the container without them, like when using granulated on a sieve bottom, granular Neutralizing agent is the case, cake to blockage areas can.

advantageous Embodiments of the invention are treated in subclaims.

In Depending on local circumstances it may be necessary, the neutralization device according to the invention Assign a pump to the purified within the neutralizer or neutralized condensate to a higher level.

As a preparatory measure for this, according to another invention, the neutralization device or the container of the neutralization device is adjacent to a last in the flow direction neutralization chamber section limiting Dividing wall divided into an upper, a condensate drain chamber forming chamber portion for receiving the wet-running rotor including pump impeller of a centrifugal pump and in a lower. Chamber section for receiving the stator of the centrifugal pump, so that it is possible without major circumstances, in the neutralization a condensate pump, preferably in the form of a ball rotor pump to integrate or install, the delivery line of this pump can be connected, for example by means of a hose to the condensate drain ,

According to one Another preferred embodiment provides that in the neutralization device or in the container the neutralization device already installed a condensate pump It must be ensured that this condensate pump has a in the condensate drainage chamber integrated wet-running part and a relative to this wet area isolated electrical Part in the form of a stator and related having electrical elements.

The Invention will become more apparent in the following with reference to the drawings described.

1 shows a schematic representation of a plan view of the device according to the invention with the container lid removed;

2 also schematically shows a view in the direction of arrows II-II in 1 ;

3 shows a schematic representation of a view in the direction of the arrows III-III;

4 shows in isometric view a plan view of the arranged in a partially illustrated neutralization neutralization structure with associated partitions;

5 shows accordingly 4 a neutralization structure usable as a module in a neutralization tank;

6 shows in exploded view a plurality of individual elements of the neutralization unit according to the 4 and 5 ,

7 shows a schematic representation of a system for optional extension of the device by a pump;

8th to 10 schematically show preferred arrangements of neutralizer structures.

The in the 1 to 3 illustrated inventive device has a substantially cuboid container 1 with a floor 2 , two longitudinal walls 3 and 4 , two end walls 5 and 6 and a lid 7 , The container 1 is by means of a extending over a part of the container length partition 8th extending from the container bottom 2 to the container lid 6 extends, divided into adjacent container sections. The condensate inlet 9 and the condensate drain 10 are located in the area of the front wall 6 of the container 1 ,

The 1 to 3 show the container 1 without the in the 4 to 6 and 8th and 9 illustrated neutralizer structures.

The condensate inlet 9 flows into a through a partition 12 limited particulate settling chamber 11 to which a filter chamber 13 follows, in which an activated carbon filter 14 can be accommodated. On the filter chamber 13 follows a Kondensatumlenkkammer through a front wall 15 and a back wall 20 is limited and followed by the actual neutralization area. The top of the partition 12 has an opening, preferably in the form of an overflow weir, between the settling chamber 11 and the filter chamber 13 ; the front wall 15 in turn forms an overflow weir between the filter chamber 13 and the condensate deflecting chamber.

The neutralization area is on the inlet side through the partition wall 20 limited, whose lower edge above the ground 2 lies, in such a way that over the upper edge of the front wall 15 flowing condensate deflected and down into the Kondensatzulaufkammer 20a flows. A condensate drain 10 upstream condensate drainage chamber 22 is through a partition 21 from the neutralization area 20a demarcated. In the area of the top of the partition 21 there is an opening, z. B. in the form of an overflow weir, for the neutralization chamber leaving condensate.

In 4 is part of a part of the container 1 with the container bottom 2 and the two container longitudinal walls 3 and 4 shown. Between the container longitudinal walls 3 and 4 and the partition 8th are parallel with each other at a lateral distance, in 1 Dashed lines indicated longitudinal walls 50 arranged from the tank bottom 2 up to the container top and thus up to the in 4 not shown container lid. These longitudinal walls 50 are each on either the container longitudinal wall 3 or the container longitudinal wall 4 facing end at the top or at the bottom with openings or recesses 50.1 respectively. 50.2 Mistake.

Between adjacent longitudinal walls 50 are vertically aligned transverse walls 52 and 53 appropriate. The first group forming transverse walls 53 are at a distance above the ground 2 and ends at a relatively short distance from the top edge of the longitudinal walls 50 , The second group forming transverse walls 52 extend from the container bottom 2 up to a height below the top of the transverse walls 53 the first group lies. The upper edges of the transverse walls 53 lie substantially in the same height as the openings or through the recesses 50.1 formed overflow weirs.

In 6 showing in exploded view a plurality of successive assemblies I, II, III and IV, each consisting of longitudinal walls 50 as well as transverse walls 52 and 53 In the region of the assemblies III and IV, the flow pattern of the condensate is represented by the arrows in the event that there are no obstructions or blockages in the region of the individual neutralization chamber sections bounded by the longitudinal walls and transverse walls. The flow from the assembly III in the region of the assembly IV is perpendicular to the longitudinal wall 50 through which in the lower floor area of this longitudinal wall 50 located recess 50.2 ,

In 6 is the case in the region of the assembly I, the case that in the bottom region of the two middle chamber sections a blockage has occurred, so that the condensate can then not flow smoothly from the first, right-lying chamber section in the subsequent chamber section. The flow then accumulates in the area of the higher transverse wall 53 and follows the arrow in the chamber section shown on the left in the region of the assembly I, from which it then passes through the lower opening 50.2 flows into the region of the assembly II. Should there be a blockage in the region of the left-hand chamber section of the first module I or a subsequent module, then the flow would be via the overflow weirs 50.1 take place from the one module in the next module.

In the 4 and 6 is in the region of the first module I, the front longitudinal wall for reasons of clarity not shown.

As it is in 6 is shown in the region of the assembly II, form the located between two successive chamber sections in the flow direction transverse walls 52 ; 53 Overflow weirs, which have alternately different height positions, and that the walls 52 with the lower level weir weirs extend to the bottoms of the neutralization chamber sections.

Instead of Of the illustrated four modules, the inventive Device any other number of consecutive modules contain.

5 shows a structure in which the individual longitudinal walls 50 with their ends on sidewalls 54 and 55 connected, whereby a module-like assembly A is formed, which in their dimensions so to the base container 1 is adapted that this modular assembly A in any number as a unit in the container 1 can be used.

The upper areas of the partitions 50 and the transverse walls 52 consist of neutralizing agent or have a coating of neutralizing agent, while the lower sections 50 ' respectively. 52 ' have no neutralizing agent.

The Distances between the longitudinal walls and the transverse walls can be changed, as well like the number of longitudinal and transverse walls.

According to 7 is the on the partition 21 following section of the container 1 divided into an upper, the condensate drainage chamber 22b forming chamber section for receiving the wet-running rotor 43 including pump impeller of a centrifugal pump and a lower chamber section 22a for receiving the stator 44 the centrifugal pump. The support line 48 the condensate pump is according to line 48a to the condensate drain 10 connected.

Between the lower and upper chamber sections 22a . 22b There are partitions that form a floor section 2a included above the level of the tank bottom 2 lies. The bottom section 2a is on its top with bearing elements for supporting the rotor 43 including the pump impeller. So contains the bottom section 2a a dent 2a ' for receiving and supporting the rotor 43 and Pumpenlaufrades preferably a spherical motor pump, which is designed according to the principle of a so-called canned pump to ensure a strict separation between the wet area of the pump on the one hand and the electric range of the pump on the other.

The stator 44 located on one in the lower chamber section 22a used and common electrical connections and control systems comprehensive board 41 , For controlling the pump, a sensor is provided, consisting of a within the chamber section 22b located transmitter 46 and a receiver 42 directed upwards into a chamber section 22c protrudes, with the chamber section 22a communicating at one along a guide 45 movable float 46.1 is attached.

8th shows a partition 50 with adjoining transverse walls 52 . 53 and an accumulation of neutralizing agent or neutralizing agent coated rods 60 which may be inserted into one or more neutralization chamber sections.

9 shows a partition 50a with vertical grooves 50a ' is provided in the transverse walls 52a respectively. 53a are inserted.

1 shows several on a plate 61 fortified neutralizing agent or neutralizing agent coated columns 62 , This structure serves to make the pillars 62 from above to mount in one or more neutralization chamber sections.

In order to avoid possible blockages or possibly dissolve is in or on the container 1 a in 1 schematized vibration generator 34 attached, the z. B. in one on the end wall 5 arranged bag 33 is used, which is preferably accessible from the outside. The power supply of both the vibration exciter 34 as well as the centrifugal pump via lines shown only indicated 35 respectively. 80 ,

According to another invention is provided, the container 1 or to associate blowing means with the individual neutralization chamber portions to inject air or gas into the apparatus during operation of the apparatus to prevent deposits from settling to the bottoms of the neutralization chamber portions. In this way it can be achieved that any flocculation or other interfering media are transported with the condensate flowing through the device to the condensate outlet.

Around as fast as possible and without much effort Check neutralization effect and check to be in the range of individual neutralization chamber sections are preferred externally accessible measuring points not shown intended for the attachment of measuring probes.

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

• EP 0174349 B1 [0003]
• - DE 3540164 A1 [0004]
• - DE 9311083 U1 [0005]

Claims (31)

Apparatus for neutralizing acidic combustion condensates, comprising a container containing a neutralizing agent, having a feed and an outlet for the condensate, characterized in that the neutralizing agent is accommodated in the container in the form of wall surfaces along which the condensate flows. Device according to claim 1, characterized in that the container ( 1 ) is partitioned by partition walls with neutralizing agent containing wall or surfaces in separate neutralization chamber sections such that the condensate is the container ( 1 ) flows through at least partially meandering. Apparatus according to claim 2, characterized in that the successive neutralization chamber sections on the one hand by extending parallel to the flow direction of the condensate longitudinal walls ( 50 ) and on the other hand by substantially perpendicular to the flow direction of the condensate aligned transverse walls ( 52 . 52 ), that the transverse walls forming a first group ( 53 ) are arranged at a distance above the bottoms of the neutralization chamber sections and their upper edges below the upper edges of the longitudinal walls ( 50 ), and that the transverse walls forming a second group ( 52 ) extending from the bottoms of the neutralization chamber sections to a height below the top edges of the transverse walls ( 53 ) of the first group is, and that the transverse walls of both groups are each arranged alternately to each other. Apparatus according to claim 3, characterized in that the successive neutralization chamber sections in a substantially cuboid container ( 1 ) are housed and on the one hand by spaced apart and mutually parallel longitudinal walls ( 50 ), which are located between opposite side walls ( 3 . 4 ) of the container ( 1 ) preferably between these side walls and a partition ( 8th ) and have substantially the same height as these partition and side walls, and on the other hand by between these longitudinal walls ( 50 ) extending transverse walls ( 52 . 53 ), that the transverse walls forming a first group ( 53 ) at a distance above the ground ( 51 ) of the neutralization chamber sections are arranged and their upper edges below the upper edges of the longitudinal walls ( 50 ), and that the transverse walls forming a second group ( 52 ) extending from the bottoms of the neutralization chamber sections to a height below the top edges of the transverse walls ( 53 ) of the first group is that the transverse walls of both groups are each arranged alternately to each other, and that the longitudinal walls ( 50 ) on either the tank longitudinal wall ( 3 ) or the container longitudinal wall ( 4 ) facing end alternately at the top or at the bottom with openings or recesses ( 50.1 respectively. 50.2 ) are provided, which at the top of the longitudinal walls ( 50 ) located openings or recesses form overflows, which are substantially at the same height as the upper edges of the transverse walls ( 53 ) of the first group. Apparatus according to claim 2, characterized in that a plurality of neutralization chamber sections are combined in a modular manner into a substantially block-shaped block (A), which has two opposing side walls (A). 54 . 55 ), between which spaced apart and mutually parallel longitudinal walls ( 50 ) are arranged, which are substantially the same height as these side walls ( 54 . 55 ) and between which transverse walls ( 52 . 53 ) are arranged such that the transverse walls forming a first group ( 53 ) at a distance above the ground ( 51 ) of the neutralization chamber sections are arranged and their upper edges below the upper edges of the longitudinal walls ( 50 ) that the transverse walls forming a second group ( 52 ) starting from the bottoms of the neutralization chamber sections via the sieve trays ( 51 ) extend to a height below the upper edges of the transverse walls ( 53 ) of the first group is that the transverse walls of both groups are each arranged alternately to each other, and that the longitudinal walls ( 50 ) on either the side wall ( 54 ) or the side wall ( 55 ) facing end alternately at the top or at the bottom with openings or recesses ( 50.1 respectively. 50.2 ) are provided, which at the top of the longitudinal walls ( 50 ) located openings or recesses form overflows, which are located substantially at the same height as the upper edges of the transverse walls ( 53 ) of the first group. Device according to one of claims 2 to 5, whose container ( 1 ) by means of a lid ( 7 ) is closable, characterized in that on the flow direction last neutralization chamber section a the condensate drain ( 10 ) condensate drainage chamber ( 22 ; 22a ) separated from the last neutralization chamber section by a partition wall ( 21 ) is separated, which in its upper part a the neutralization chamber section with the condensate drain chamber ( 22 ; 22a ) connecting opening preferably. in the form of an overflow weir. Apparatus according to claim 6, characterized in that the liquid feed ( 10 ) in a particulate settling chamber ( 11 ), to which an activated charcoal filter ( 14 ) receiving filter chamber ( 13 ), which precedes the neutralization chamber sections. Apparatus according to claim 7, characterized in that between the settling chamber ( 11 ) and the filter chamber ( 13 ) a partition wall ( 12 ) is arranged with an overflow weir located on its upper side. Device according to one of claims 3 to 8, characterized by a first neutralization chamber section upstream partition wall ( 20 ) with an overflow located on the top of the bulkhead, this channel being followed by a channel leading to a liquid inlet opening (below the bottom of the sieve of the first neutralization chamber section) (US Pat. 20a ) leads. Device according to one of claims 1 to 9, characterized in that it comprises a condensate discharge upstream chamber, which is divided into an upper, the condensate discharge chamber forming chamber portion ( 22b ) for receiving the wet-running rotor ( 43 ) including the pump impeller of a centrifugal pump and into a lower chamber section ( 22a ) for receiving the stator ( 44 ) of the centrifugal pump. Apparatus according to claim 10 characterized by a between the upper and lower chamber sections ( 22a ; 22b ), which has a bottom section ( 2a ), which above the level of the container bottom ( 2 ) lies. Apparatus according to claim 11, characterized in that the bottom portion ( 2a ) has on its upper side bearing elements for supporting the rotor including the pump impeller. Apparatus according to claim 10 or 11, characterized in that the bottom portion ( 2a ) with a recess ( 2a ' ) is provided for receiving and supporting the wet-running rotor and pump impeller of a spherical motor pump. Device according to one of claims 10 to 13, characterized in that the upper chamber portion ( 22a ) a holder ( 47 ) for attachment to a transmitter ( 46 ) ( 45 . 46 ) having. Device according to one of claims 10 to 14, characterized in that the lower chamber section ( 22b ) an upward chamber extension ( 22c ) having. Device according to one of claims 10 to 15, characterized in that in the lower chamber section ( 22a ) the stator ( 44 ) and in the upper chamber section ( 22b ) the rotor ( 43 ) including pump impeller of a condensate pump are housed, wherein the delivery line ( 48 ) of the condensate pump to the condensate drain ( 10 ) connected. Device according to one of claims 10 to 22, characterized in that the condensate pump is a ball-rotor pump whose wet-running part, consisting essentially of rotor and pump impeller in the upper chamber section ( 22b ), while the stator is located in the region of the lower chamber section ( 22a ) is located. Apparatus according to claim 16 or 17, characterized in that they are for controlling the condensate pump, a sensor ( 42 . 46 ), one in the region of the upper chamber portion ( 22b ) ( 46 ), one at the other along a guide ( 45 ) movable floats ( 50 ), and one in the region of the lower chamber portion ( 22a ) ( 42 ). Device according to one of claims 1 to 18, characterized by a in or on the container ( 1 ) vibration exciters ( 34 ). Device according to one of claims 1 to 19, characterized in that at least some of the neutralizing agents having wall surfaces by plates of neutralizing agent are formed. Device according to one of claims 1 to 20, characterized in that at least some wall surfaces are formed by insert body of any shape, the Neutralization agent included. Device according to one of claims 1 to 21, characterized in that the neutralizing agent-containing Wall surfaces as a coating material on base body or base plates are applied. Device according to claim 22, characterized in that that the coating material is in the form of films. Device according to claim 22, characterized in that that the coating material is sprayed on. Device according to one of claims 1 to 24, characterized in that the neutralizing agent-containing Wall surfaces a roughened or structured surface to have. Device according to one of claims 1 to 25, characterized in that the Neutralisati Onsmittel containing wall surfaces are interchangeably inserted into the container. Device according to one of claims 1 to 26, characterized by in the container ( 1 ) suspendable inserts having plate or columnar structures with surfaces containing neutralizing agents. Device according to one of claims 1 to 27, characterized in that the neutralizing agent having wall surfaces lower, neutralizing agent-free Connect wall sections. Device according to one of claims 1 to 28, characterized in that at least some insert body have the shape of columns that at least over a part of your height consist of neutralizing agent or coated therewith. Device according to one or more of the preceding claims, characterized in that it has partitions ( 50a ) provided with vertical slots ( 50a ' ) for the interchangeable insertion of transverse walls ( 53a ) are provided. Device according to one of claims 1 to 30, characterized in that they include means for blowing of air or gas.