EP1131558B1 - Method for conveying damp gases by means of a conveyor device and conveyor device for carrying out said method - Google Patents

Abstract

The invention relates to a process for conveying damp gases by means of a conveyor device (1) and also relates to a conveyor device (1) for carrying out the process. The conveyor device (1) has at least one feed pump (2) with an oscillating reciprocating piston (3) in a delivery chamber (7). In order to dry the conveyor device (1) effectively in the region of the delivery chamber (7), the delivery chamber (7) of at least one feed pump (2) is intermittently ventilated at various intervals in time using an ventilation device (15) while the conveyor device (1) is in operation.

Description

The invention relates to a method for conveying moist gases by means of a delivery device, the at least one delivery pump with a displacer oscillating in a delivery chamber. The invention also relates to a conveyor, in particular to carry out the method mentioned at the beginning, with at least one feed pump, one in a feed chamber has oscillating displacers and their delivery space a Inlet with at least one suction valve and an outlet with has at least one exhaust valve, at least one Feed pump of the conveyor with a ventilation device has a ventilation duct that opens into the area of the delivery chamber and wherein a ventilation valve is interposed in the ventilation duct is, if necessary and independent of the Stroke position of the displacer can be actuated.

A conveyor device is already known from DE 296 18 911 U1 of the type mentioned with a diaphragm pump, which Conveyor especially for the evacuation of the Completion of dentures or dental prostheses needed Kilns serves. In order to start this conveyor easily to enable even with already generated negative pressure the known conveyor has a ventilation valve for the pump work space of the diaphragm pump. This vent valve is in the flow direction behind the inlet valve connected to the pump workspace so that the suction pipe the diaphragm pump are kept clear of the ventilation valve and the ventilation valve has no influence on the passage cross-section for the pumped medium.

The ventilation valve in the previously known from DE 296 18 911 U1 Conveyor is solely intended to be inexpensive Way also a trouble-free start of the pump arrangement existing vacuum in the intake line and at the same time to ensure high pump performance at low cost. The conveyor device known from DE 296 18 911 U1 however neither suitable nor intended to convey moist gases, such as during the operation of an autoclave attack.

Medical instruments and other medical commodities are sterilized in autoclaves, the one have air-tight lockable sterilization chamber. there the instruments in the sterilization chamber before the sterilization process, a so-called fractionated backing vacuum, in which by repeated Evacuation of the air alternating with the periodic inflow a particularly good air removal from steam, also from narrow spaces Instruments is achieved. During the sterilization process the instruments in the sterilization chamber are under pressure exposed to hot steam. To the instruments after Sterilize quickly and residue-free to dry Sterilization chamber then a so-called Post vacuum creates the drying time of the items to be sterilized shorten and optimize the drying process.

The sterilization chamber is more well known for evacuating Steam sterilization devices on a conveyor connected, which has a vacuum pump. Because of the So far, the vacuum pump has been exposed to water vapor only water ring pumps or diaphragm pumps are used. Because of the Size and the disadvantages of a water ring pump come in the for example, smaller ones intended for the doctor's office Steam sterilization devices mostly only apply to membrane pumps.

However, when using conventional diaphragm gas pumps the risk that those occurring when conveying moist gases Liquid droplets for sticking the gas valves and thus for Interruption of the evacuation process. About that in addition, when drilling out the flow channels in End cover of the pump head pockets that are hard to avoid also lead to an accumulation of fluid, causing further evacuation is made even more difficult.

To achieve evaporation of the water droplets and around you trouble-free operation of the known conveyor systems To ensure the pump heads are specially designed membrane pumps used in steam sterilizers heated to approx. 100 ° C. With the evaporation of the in the production gas However, the liquid contained is a considerable increase in volume of the pumped medium, which leads to an increase the evacuation time. In addition, hot act Pump heads negatively affect the life of the used Membranes, valves, bearings and other components. This negative effects are exacerbated by the already high Ambient temperature intensified in the housing of such Steam sterilizers through steam generation arises.

In addition, those required to heat the pump heads are required Cartridge cartridges are relatively expensive because they are additional a control device for these heating cartridges Temperature sensor for regulating the evaporation temperature must be used, and because these heating cartridges mostly need at least as much electrical power as that Drive motor of the associated feed pump.

There is therefore the task of a method and a device of the type mentioned at the beginning, with which a simple and trouble-free conveyance of moist gases is possible without thus an increased use of electrical energy and an increased Wear of the feed pumps used would be connected.

The inventive solution to this problem consists in the Process of the type mentioned in particular in that the Delivery space of at least one feed pump during the operation of the Conveyor as required and regardless of the stroke position of the displacer oscillating in the delivery chamber once or several times is ventilated intermittently.

A device is already known from US-A-2 812 893 as a combination of a suction pump and a compressor is trained. The known device works with Downstroke of the piston as a suction pump, while on the upstroke serves as a compressor. The piston opens during the Downward stroke on the cylinder circumference provided valve openings, so additional air into the displacement under atmospheric pressure from outside flow in and are compressed in the subsequent upward stroke can, because the air sucked in through the inlet valve to the Compression alone may not be enough.

The device known from US-A-2 812 893 has compression spring loaded Intake and exhaust valves at a defined Open the pressure difference temporarily. Opens the exhaust valve of the previously known device, for example, at an overpressure of 10 bar, so the compressed during the upward stroke and 10 bar Excess air is expelled through the exhaust valve. in the The upper dead space then only remains below this pressure limit is the amount of air. Because this is harmful Air volume still has a gas pressure of 10 bar, it would normally push the plunger down so that the previously known device does not function as a downward stroke Suction pump can take over. The previously known device shows in her pump head therefore a vent valve, which means an actuating rod arranged on the piston at top dead center is opened. The actuation of the in the known device Vent valve used is therefore cyclical and in Dependence on the stroke position of the piston.

In the method according to the invention, the delivery space is at least a feed pump, on the other hand, if necessary and independent of the stroke position of the displacer once or at time intervals ventilated several times. This will be in the funding room any remaining liquid droplets from the conveyor blown out. The pumping room can be ventilated during the operation of the feed pump once or several times for example after certain condensation times or at different pressure levels in one by means of the conveyor chamber to be evacuated. Since in the invention Process a quick and targeted pump drying the moisture contained in the fluid handled condensed, the delivery chamber cooled and accordingly on energy-consuming heating of the pump head can be dispensed with. This is a preferred further development according to the invention before that the feed pump in the area of their delivery space under the evaporation or existing at a given evacuation pressure Boiling temperature is cooled. By cooling the damp The medium is also the volume of the original vaporous medium during the condensation on Fraction of the original volume reduced. Through this Volume reduction occurs in the area of the conveyor Condensation pump effect, which increases the delivery rate of the Conveyor determines or at least supports. Since the Feed pump under the existing at a given evacuation pressure Evaporation or boiling temperature is cooled, a Regasification of the already condensed medium in the area the feed pump is definitely excluded. Because in particular in a steam sterilization device in the medium contained water vapor cooled and in its liquid state is transferred, the feed pump has only a smaller one Pump out the volume of the pumped medium, resulting in the required Pump operating time significantly reduced. The for Cooling of the pumped medium in the area of the pumping room required Cooling the feed pump also causes at the same time a cool run of the conveyor, which is a long Lifetime of the feed pump and long service intervals favored.

The ventilation of the delivery chamber according to the inventive method can also be done manually. However, to the effort and the The solution according to the invention is to facilitate handling in the conveyor of the type mentioned in particular in that the ventilation valve with a control device in Control connection is, and that the control device Has timer and / or a pressure sensor, for a one-time or repeated intermittent actuation of the ventilation valve in Depending on the condensation time and / or depending predetermined pressure levels in a by means of the conveyor chamber to be evacuated.

Around the liquid droplets that may remain in the feed pump Blow out from all areas of the delivery room if possible to be able to see a preferred embodiment according to the Invention before that the delivery chamber with the suction valve on a Suction channel is connected and that the ventilation channel in the suction channel preferably opens directly in the area of the suction valve, If the suction and / or outlet valves of the ventilation device having feed pump as usual depending on the pressure prevailing in the delivery chamber can be actuated when opening the ventilation valve and when venting the The suction valve of the feed pump is suddenly closed, which also serves as a check valve acts against the chamber to be evacuated by the pumped medium. This ensures that when the ventilation valve is actuated a targeted flow with a sufficiently high flow velocity is built up to the liquid droplets that have remained in the delivery chamber so far entrain.

Since the suction valve also opens when the ventilation valve is opened abruptly closes, the ventilation or Take drying gas one way only and from the pump inlet side directly through the delivery chamber to the pump outlet side stream. This measure ensures effective pump drying favored.

To make a multi-stage conveyor practically complete to be able to ventilate and dry it, it is advantageous if the the feed pump having the ventilation device is the first Pump stage of the multi-stage conveyor forms.

It is advantageous if the pump stages of the conveyor are connected via a flow channel, the Channel cross-section is selected so that the flow force is greater as an adhesive force and in particular that is an atmospheric Volume flow of the conveyor an average flow rate greater than 10 m / sec. generated. This flow rate creates a frictional force at the boundary layer between ventilation gas and adhesive liquid that is larger than the adhesive force between the liquid and that in the delivery chamber provided flow surfaces. This ensures that the liquid droplets remaining in the delivery chamber detach from the flow surfaces of the delivery chamber and with the Ventilation or drying gas are entrained.

The drying of the pumping room is additionally supported, if the conveyor device, at least in some areas, preferably at least in the area of the pump head of the feed pump (s) Low-adhesion and especially non-metallic flow surfaces which has very low adhesive binding forces to liquids exhibit. It can be particularly advantageous if the Flow surfaces of the conveyor at least in one Part of a plastic coating, preferably one Teflon coating.

To collect even the smallest liquid droplets in the area to complicate the funding area, it is useful if the Pump head of the feed pump (s) at least in the area of a End cover as a die-cast part, preferably with molded blind hole-free flow channels is formed. Because with this Pump design the flow channels in the die-cast part trained pump head are molded, the at Drilling the flow channels so far unavoidable Pockets and blind holes avoided, in which the Could collect liquid.

After further training according to the invention of its own It is envisaged that the pump head of the Feed pump (s) is forced cooled and that at the pump head Delivery pump (s) on the outside preferably cooling fins for forced air cooling are provided. Because the pump head at this is further cooled embodiment, the Head temperature also below the given evacuation pressure Existing evaporation or boiling temperature are cooled. This further development according to the invention ensures that the water vapor contained in the medium condense and cannot evaporate again. A re-evaporation of the Condensate would have an undesirable increase in volume of the medium and a corresponding extension of the necessary operating times of the conveyor result.

A preferred embodiment according to the invention provides that between the pump head and a crankcase Feed pump (s) an intermediate cover or an intermediate plate is arranged, in which the between the delivery room and the Valves provided flow channels are provided and that the intermediate cover is designed as a plastic part. Because due of the ventilation valve provided according to the invention Heating up the pump head can be avoided and because of that subject of the present invention a condensation in Fluid contained is preferred, the can Intermediate cover, for example as an injection molded part from one Plastic are made. Such a plastic part and in particular a plastic injection molded part has a very smooth, water-repellent surface, which creates the adhesive effect even more can also be reduced. It also trains Plastic-made intermediate cover a bad one Thermal conductor that provides effective thermal insulation between the hot Pump head and the pump housing forms. Because the plastic manufactured intermediate cover compared to, for example pump head made of aluminum remains relatively cool a condensation of the moisture contained in the medium and a rapid removal of the moisture droplets in the area this intermediate cover favors. In addition, one can Plastic and especially as a plastic injection molded part manufactured intermediate cover can be produced very inexpensively.

A preferred embodiment according to the invention provides that the feed pump (s) of the conveyor, in particular the the ventilation device pointing to the feed pump, as a reciprocating piston pump or is preferably designed as a diaphragm pump.

If the conveyor device has a flow guide with at least has a tubular channel section, an optimization the flow guidance can be achieved when this channel section at the end with an adjacent section of the flow guide by means of a sealing ring made of elastic material in the is essentially seamlessly connected. Thus, also in this Avoiding joints and other dead spaces in the area of flow guidance in which the condensate could otherwise collect.

Further features of the invention result from the following Description of exemplary embodiments according to the invention in connection with the claims as well as the drawing. The individual characteristics can be used individually or in groups in one embodiment be realized according to the invention.

Fig. 1

eine als Membranpumpe ausgebildete Förderpumpe mit einer Belüftungseinrichtung, deren Belüftungskanal im Bereich des Förderraums der Pumpe mündet, und

Fig. 2

eine zweistufige Fördereinrichtung, die zwei Förderpumpen hat, von denen die erste Pumpstufe eine Belüftungseinrichtung aufweist.

It shows in a schematic representation:

Fig. 1

a feed pump designed as a diaphragm pump with a ventilation device, the ventilation channel of which opens in the region of the delivery chamber of the pump, and

Fig. 2

a two-stage delivery device which has two delivery pumps, of which the first pump stage has a ventilation device.

1 shows a feed pump in a longitudinal section, which is designed here as a diaphragm pump 2. The diaphragm pump 2 has a thin elastic and serves as a displacer Shaped membrane 3, which is fixed between its circumference Pump head 4 and a pump housing 5 is clamped. The Formed diaphragm 3 of the diaphragm pump 2, which uses a connecting rod 6 is moved between them and the pump head 4 a funding room 7.

The pump head 4 of the diaphragm pump 2 is essentially in two parts formed and has an intermediate cover 8 and a End cover 9 on. In the pump head 4 of the diaphragm pump 2 in each case an inlet 10 with a suction valve 11 and an outlet 12 provided with an outlet valve 13. The suction valve 11 and that Outlet valve 13 of the feed pump 2 are dependent on the pressure prevailing in the delivery chamber 7 can be actuated. The valves For this purpose, 11, 13 have a valve body 14, which as one of a Elastomer existing valve disc is formed. This Valve disks can also be tongue-shaped or round, for example be trained.

The diaphragm pump 2 is otherwise not part of one conveyed device 1, which is used to convey moist Serves gases. Such funding facilities are, for example Evacuation of steam sterilization devices (so-called Autoclaves) or in the field of gas drying.

To avoid the moisture contained in the gaseous medium condense, reduce the delivery volume and for example time required to evacuate a steam sterilization chamber To keep it as small as possible, the pump head 4 is Feed pump 2 forced-cooled. The pump head 4 can do this For example, have a water cooling system, the cooling channels very close and parallel to those in the pump head Gas flow channels are arranged. However, one is preferred Embodiment in which the pump head 4 in particular its end cover 9 in addition to or instead of water cooling Cooling fins not shown here for forced air cooling having.

With the help of this forced cooling, the feed pump 2 becomes such forced-cooled so that it is below the existing evaporation or boiling temperature in the gaseous Liquid contained in the fluid is cooled, which in the evacuation pressure to be evacuated equivalent. Due to the cooling of the moist pumped medium at the same time the volume of the originally vaporous Fluid during the condensation to a fraction of the original volume reduced. Through this volume reduction a condensation pump effect occurs in the area of the conveyor, which is the conveying capacity of the conveying device 1 supported. Since the water vapor contained in the pumped medium Area of the feed pump 2 cooled and in its liquid The delivery pump has only one physical state pump out less volume of the pumped medium, resulting in the required pump operating time is significantly reduced. The for Cooling of the pumped medium in the area of the pumping room 7 necessary cooling of the feed pump 2 also causes a cool run of the conveyor 1, which is a long Lifetime of the feed pump and long service intervals favored.

In order for the suction valve 11 and the outlet valve 13 to stick together due to the liquid droplets contained in the medium avoid and to prevent rapid evacuation Accumulation of the liquid in any dead spaces of the To prevent feed pump 2, the delivery chamber 7 during the Operation of the feed pump 2 vented intermittently at time intervals. The time intervals can depend on those in the to be evacuated (steam sterilization) chamber Pressure levels and / or the condensation times can be controlled.

For this purpose, the diaphragm pump 2 has a ventilation device 15 a ventilation duct 16 which opens into the area of the delivery chamber. A ventilation valve 17 is interposed in the ventilation channel 16, which is in control connection with a control device stands. To set the ventilation device 15 in or to be able to operate preselectable time intervals, the Control device on a timer or the like timer. In addition or instead, the control device can also be used one, for example, in the steam sterilization chamber Autoclave pressure sensor connected if that Ventilation valve 17 in dependence on predetermined pressure levels of the chamber to be evacuated. By the intermittent ventilation of the delivery room 7 in the delivery room 7 any remaining liquid droplets from the conveyor 1 blown out. The ventilation of the delivery chamber 7 can staggered several times during the operation of the feed pump 2 for example after certain condensation times or Pressure levels take place. Since by means of the ventilation device 15 quick and targeted pump drying can be achieved, the moisture contained in the fluid can condense, the pumping room cooled and accordingly on an energy-consuming Heating up the pump head 4 can be dispensed with.

1 shows, the delivery chamber 7 with the suction valve 11 is over a suction channel 18 connected. Around the delivery room 7 if possible To be able to blow out completely, the ventilation duct 16 opens the ventilation device 15 in the flow direction of the pump inlet 10 immediately behind the suction valve 11 in the suction channel 18th

When venting the delivery chamber 7, the suction valve 11 closes Diaphragm pump 2 suddenly. The ventilation or Take drying gas one way only and from the pump inlet side Flow over the delivery chamber 7 to the pump outlet side. The actuation of the ventilation device 15 causes that in the Feed pump 2 a targeted flow with a very high Flow rate is built up, which is the in the pumping chamber 7 entrained liquid droplets. The one in the gaseous Liquid contained in the pumped medium is after its condensation in the pump head 4 by clocking the ventilation device one or more times 15 specifically promoted from the feed pump 2. Will the Conveyor 1 for example for evacuating the steam sterilization chamber an autoclave or a vacuum drying cabinet used, the evacuation time with the help of Ventilation device 15 significantly shortened and the final vacuum be improved.

The ventilation valve 17, which is also a manually operated valve can be formed here is an electromagnetic valve trained and integrated directly into the intermediate cover 8. This Intermediate cover 8 is designed as a plastic injection molded part, which is characterized by a very smooth, liquid-repellent surface distinguished.

Because the plastic intermediate cover is inexpensive 8 forms a very poor heat conductor, it can be effective Thermal insulation between pump housing 5 and end cover 9 Act. The moisture contained in the gaseous medium can in the cooler compared to the cooled cover 9 Condense intermediate cover 8 well.

In the area of the force-cooled cover 9, on the other hand an intensive heat exchange is desired to the released Quickly dissipate the heat of condensation and cool the pump head to be able to. The end cover 9 is therefore a die-cast part preferably made of aluminum. In this die-cast aluminum part are those provided for the medium Gas flow channels formed without blind holes. This makes bags and largely avoided other dead spaces that would otherwise occur during subsequent drilling of such channels arise and in which the liquid can accumulate. To cling to the To prevent moisture in the pump inlet and pump outlet the pump head 4 is also non-metallic in the area of its end cover 9 Flow surfaces. These flow surfaces are designed in the area of die-cast aluminum End cover 9 by a plastic coating, in particular a Teflon coating.

As shown in Figure 2, the feed pump shown in Figure 1 can 2 can also be part of a multi-stage conveyor device 100. In the two-stage and formed from the diaphragm pumps 2, 2 ' The conveyor device 100 is the ventilation device 15 having diaphragm pump 2 provided as the first pump stage, the Pump outlet 12 via a tubular channel section 19 with the pump inlet 10 of the diaphragm pump 2 'is connected. This Channel section 19 is with its ends in connection openings 20 of the pumps 2, 2 'held, these ends of the Channel section 19 each with the adjacent portion of the Flow guidance by means of a sealing ring 21 joint and is seamlessly connected. Also in the channel section 19 two-stage conveyor 100 is the channel cross section of the Flow channel chosen so small that an atmospheric Volume flow of the equipped with the ventilation device 15 Feed pump 2 has an average flow rate greater than 10 m / Sec. generated.

In the conveyor devices 1, 100 shown here, the Pump heads 4 of the feed pumps 2, 2 'cooled in such a way that the Condensate moisture contained in the gaseous medium can. The condensation is carried out, for example, as air and / or Water cooling trained forced cooling of the pump heads 4 reached. Through flow-optimized and coated flow guides the condensate in the conveyors 1, 100 transported without liability. A condensation occurs drastic volume reduction, resulting in fast pumping times and achieve high pumping capacities. With the help of the Delivery pumps 2 provided ventilation device 15 can fast and targeted drying of the conveyor systems 1, 100 can be achieved, thereby shortening the evacuation time additionally favored and the achievable final vacuum can be significantly reduced. Since the ventilation duct 16 of Ventilation device 15 opens into the delivery chamber 7 of the delivery pump 2, can do this depending on the prevailing in the production area Pressure working suction valve 11 also serves as a check valve act, whereby a targeted drying of the Conveyors 1, 100 is reached.

Claims (15)

1. Process for conveying damp gases by means of a conveyor apparatus (1, 100) which comprises at least one feed pump (2, 2') having a displacement device (3) oscillating in a feed chamber (7), characterised in that the feed chamber (7) of at least one feed pump (2) is ventilated spasmodically when necessary, once or a number of times, at intervals of time during the operation of the conveyor (1, 100) and independently of the stroke position of the displacement device.
2. Process according to claim 1, characterised in that the feed pump(s) (2, 2') is or are blower-cooled in the region of the pump head (4) thereof.
3. Process according to claim 2, characterised in that the feed pump(s) (2, 2') is or are cooled, in the region of the pump head (4) thereof, to below the vaporisation or boiling temperature which prevails at a given evacuation pressure.
4. Conveyor (1, 100), particularly for carrying out the process according to one of claims 1 to 3, with at least one feed pump (2, 2') which has a displacement device (3) oscillating in a feed chamber (7) and the feed chamber (7) of which has an inlet (10) with at least one intake valve (11) and an outlet (12) with at least one outlet valve (13), wherein at least one feed pump of the conveyor has a ventilation device (15) with a ventilating channel (16) which opens out in the region of the feed chamber (7), and wherein in the ventilation channel (16) a ventilating valve (17) is interposed which can be actuated as necessary independently of the stroke position of the displacement device, characterised in that the ventilating valve (17) of the conveyor intended to convey damp gases is under the control of a control device to which it is connected, and in that the control device has a timer and/or a pressure sensor, for spasmodically actuating the ventilation valve either once or repeatedly as a function of the condensation time and/or as a function of given pressure stages in a chamber which is to be evacuated by means of the conveyor (1, 100).
5. Conveyor according to claim 4, characterised in that the feed chamber (7) is connected to the intake valve (11) via an intake channel (18) and in that the ventilation channel (16) opens into the intake channel, preferably in the immediate vicinity of the intake valve (11) .
6. Conveyor according to claim 4 or 5, characterised in that the intake and/or outlet valves (11, 13) of at least the feed pump (2) having the ventilating device (15) can be actuated as a function of the pressure prevailing in the feed chamber (7).
7. Conveyor according to one of claims 4 to 6, characterised in that the feed pump (2) comprising the ventilating device (15) forms the first pumping stage of a multi-stage conveyor (100).
8. Conveyor according to one of claims 4 to 7, characterised in that the conveyor (1, 100) has flow channels the cross section of. which is designed so that an atmospheric flow volume of the feed device (2) produces an average rate of flow of more than 10 m/sec.
9. Conveyor according to one of claims 4 to 8, characterised in that the conveyor (1, 100) has non-metallic flow surfaces at least in certain areas, preferably at least in the region of the pump head (4) of the feed pump(s) (2, 2').
10. Conveyor according to one of claims 4 to 9, characterised in that the flow surfaces of the conveyor (1, 100) have a plastic coating, preferably a Teflon coating, at least in a partial area.
11. Conveyor according to one of claims 4 to 10, characterised in that the pump head (4) of the feed pump(s) (2, 2') is constructed, at least in the region of a closure cover (9), as a die-cast component, preferably with flow channels free from blind bores formed therein.
12. Conveyor according to one of claims 4 to 11, characterised in that the pump head (4) of the feed pump(s) (2, 2') is blower-cooled, and in that cooling fins for forced-air cooling are preferably provided on the outside of the pump head (4) of the feed pump(s) (2, 2').
13. Conveyor according to one of claims 4 to 12, characterised in that between the pump head (4) and a crank housing (5) of the feed pump(s) (2, 2'), there is an intermediate cover (8) in which are disposed the flow channels provided between the feed chamber (7) and the valves (11, 13), and in that the intermediate cover (8) is preferably constructed as a plastics component.
14. Conveyor according to one of claims 4 to 13, characterised in that the feed pump(s) (2, 2') of the conveyor (1, 100), particularly the feed pump (2) comprising the ventilating device (15), is constructed as a lifting cylinder pump or preferably as a diaphragm pump.
15. Conveyor according to one of claims 4 to 14, characterised in that the conveyor (100) has a flow guide with at least one tubular channel portion (19) and in that this channel portion (19) is attached substantially seamlessly at its end to an adjacent part of the flow guide by means of a sealing ring (21) made of elastic material.

Images