WO2011069710A1 - Ventilation element for a storage tank - Google Patents

Abstract

The invention relates to a storage tank (10) for receiving a medium (12) that can be frozen, in particular a reducing agent, comprising a ventilation unit (34, 36; 72) and a crucible-shaped container (22) introduced in the storage tank (10). An air chamber (50) in the crucible-shaped container (22) is connected via a ventilation line (60) or an overflow opening (40) to an air chamber (48) of the storage tank (10), which is ventilated via a ventilation unit (34, 36; 72).

Description

 description

title

 Entlüftunqselement for storage tank prior art

In the case of motor vehicles with internal combustion engines, it is necessary, inter alia, to reduce the pollutant in NOx because of the stricter exhaust gas legislation which will be forthcoming in the next few years. One method to reduce this pollutant, and which is already in use, is the SCR (Selective Catalytic Reaction) process, according to which the pollutant NOx is reduced to N ₂ and H ₂ O with the aid of liquid reducing agent. The reducing agent is conveyed in a line from the storage tank storing the reducing agent to the metering module. Depending on the antifreeze added, the reducing agents used today usually freeze between -1 1 ° C and -40 ° C.

In order to ensure fast thawing of the frozen medium, an electric heater is installed in the storage tank within an open-bottomed pot. Thus, the heat given off by the heater is first used to thaw the contents of the pot. About a likewise heated trained suction lance, the liquid thawed around the heater is sucked through the suction lances and entered into the exhaust. The conveyor regulates a constant system pressure via the pump motor speed, the pressure sensor and a return flow restrictor. The Rückströmmenge is usually returned via a return line back into the heating pot.

Due to the outgoing from the storage tank and this incoming liquid quantities of the tank interior to the environment to vent or vent. Presentation of the invention

According to the invention it is proposed to vent the air space in the cup-shaped container via a hose into the air space of the storage tank for receiving the reducing medium. The air space of the storage tank is connected via a venting element with the environment, whereby a pressure equalization taking into account the hose line of both the air space in the pot and the air space above the tank can be carried into the environment. The venting path thus arises from the bottom of the pot via an adjusting during heating of the return line air path between the lateral surface of the return and the inside of the reducing agent present in the form of ice in the upper air space in the pot, from there via the vent line into the air space at the Top of the tank next to the cup-shaped container and from there via the venting element into the environment.

The vent line, which extends from the air space in the upper region of the cup-shaped container into the air space of the storage tank, is preferably made of a reducing agent-resistant material, such as e.g. Made of EPDM or PA12 or the like. The vent line is pushed onto both the lid of the cup-shaped container and the tank lid on appropriately trained preferably molded pins made of plastic material and, for. fastened by means of a profiled heel (Christmas tree profile).

To illustrate the wading capability of the proposed system according to the invention, therefore, only the hose connection of the venting element fastened to the upper side is to be lengthened and connected into a space permanently filled with air. This hose connection is all the more advantageous if the storage tank can be designed as a plastic injection molded component or the tank lid of the storage tank made of plastic material by way of injection molding. In this case, the connection as well as the pins for attaching the vent line can all be sprayed on the top of the tank lid directly in one operation, without the need of expensive post-processing steps.

The proposed solution according to the invention offers a simplification of the design and thus a higher robustness with lower production costs due to the omission of a number of parts. Furthermore, in the case of the invention beaten storage tank a significant simplification of assembly due to the reduced number of components and thus a considerable reduction in manufacturing costs can be achieved. In terms of watertight systems, only one hose connection is required, which also results in a great deal of simplification.

In a further advantageous embodiment of the solution on which the invention is based, an air space which extends above a frozen contents of a tank and an air space which is located above the frozen contents of a pot, which is embedded in the tank via a respective separate vent in the environment be vented. In the connection piece of a lid which closes the pot and in a connection piece for a ventilation line of the tank above an air space, in this embodiment variant of the solution proposed according to the invention, in each case tablet-shaped ventilation elements can be inserted. By provided in this embodiment, two separate vents a venting of the tank as well as a venting of the pot is possible.

Brief description of the drawings

With reference to the drawings, the invention will be described in more detail below. It shows:

1 shows a variant of a storage tank for receiving a reducing agent with a tank ventilation and a vent for a cup-shaped container in the storage tank,

FIG. 2 a representation of the attachment of a venting element in the lid of the cup-shaped container,

FIG. 3 shows a variant of the solution proposed according to the invention,

Figure 4 shows a variant of the sealing of a vent line and

Figure 5 shows a watertiges system with a vent line extending through a wet room in a drying room. Ausführunqsvarianten

FIG. 1 shows that a storage tank 10 receives a reducing agent supply 12. At low outside temperatures below -1 1 ° C, the stored in the storage tank 10 reducing agent 12 begins to freeze and it turns a solid ice-phase 14 and a liquid phase 16 in the storage tank 10 a. Depending on the additives which are mixed with the reducing agent supply 12, the reducing agent supply 12 freezes in the storage tank 10 at outside temperatures between -1 1 ° C and -40 ° C.

The storage tank 10 comprises a tank lid 18 and a tank bottom 20 and a cup-shaped container 22, which is embedded in the interior of the storage tank 10 at the top of the storage tank 10. The cup-shaped container 22 in turn is closed by a lid 32. A heatable suction lance 24 extends through the pot-shaped container 22 or the lid 32, which closes the cup-shaped container 22. Furthermore, a heater 26, which is generally operated electrically, is accommodated in the lower region of the cup-shaped container 22. Reference numeral 28 denotes the fill level of the reducing agent supply 12 in the pot-shaped container 22 as well as in the interior of the storage tank 10. On the underside of the cup-shaped container 22 is an opening 30, via which reducing agent flows continuously into the cup-shaped container 22. The lid 32 of the cup-shaped container is attached to a thread 34 by a cover screw 54. The thread 34 is formed on a correspondingly configured nozzle element of the tank cap 18, to which the cover screw 54 is screwed for fixing the lid 32 of the cup-shaped container 22.

From the illustration according to FIG. 1, it can be seen that both the storage tank 10 and the cup-shaped container 22 are aerated or vented via a respective tank vent 36 and a pot vent 38. In order to ensure an overflow of air between an air space 48 in the storage tank 10 and an air space 50 above the level 28 of the reducing agent in the cup-shaped container 22, located in the wall of the cup-shaped container 22 has an opening 40. As is apparent from the illustration in FIG However, this opening 40 is closed during freezing, since the solid phase 14 of the reducing agent 12 due to the expansion of the reducing agent by about 10% during the phase transition liquid / solid expands. Ice attaches to the underside of the tank cap 18 and an overflow of air from the air space 48 into the air space 50 is no longer possible. For this reason, the Air space 48 vented through the tank vent 36, while the air space 50 in the upper region of the cup-shaped container 22, which is closed by the lid 32, via the pot vent 38 separately vented to the outside.

As can be seen from the illustration according to FIG. 1, there is a venting element 42 both in the tank vent 36 and in the pot vent 38, which is generally tablet-shaped.

FIG. 2 shows an illustration of the attachment of the tablet-shaped venting element in the venting socket of the pot-shaped container as shown in FIG. 1.

As Figure 2 shows, the venting element 42 is employed in the neck of the tank vent 36 against a collar 44. In order to ensure the safe reception of the tablet-shaped venting element 42 below the collar 44, a hot caulking 46 may be provided which engages under the lower plan side of the tablet-shaped venting element 42 and thus reliably fixes it below the opening of the nozzle of the pot venting 38. In this way, the tablet-shaped venting element 42 is fixed on the Warmverstemmung 46 below the pot vent 38. In the embodiment shown in Figure 1, two separate vents, namely the tank vent 36 and the pot vent 38 are shown due to the forming at freezing seal between the air spaces 48 and 50.

The illustration according to FIG. 3 shows a further embodiment of the solution proposed according to the invention.

As Figure 3 shows, is located in the storage tank 10 for receiving the reducing agent supply 12 of the cup-shaped container 22. At low outside temperatures between - 1 1 ° C and -40 ° C - depending on the addition of antifreeze to the reducing agent supply - arises both within the storage tank 10th as well as within the cup-shaped container 22, a phase separation of the reducing agent supply 12 in the solid egg-shaped phase 14 and in the liquid phase 16 a. As a result, the above-mentioned air spaces 48 and 50 arise above the fill level 28 both in the cup-shaped container 22 and in the storage tank 10. While the cup-shaped container 22 is closed by the lid 32, the air space 48 of the tank is replaced by the tank cap 18. concluded. The two air spaces 48 and 50 are separated from one another by a sealing point 68, against which the solid, ice-like phase 14 of the reducing agent supply 12 rests against the underside of the tank lid 18, so that the two air spaces 48 and 50 are cut off from each other and no air exchange takes place between them can.

In the lid 62 of the pot-shaped container 22, a first port 62 is formed in the form of a pin, which serves to receive a vent line 60. The vent line 60 extends from the first port 62 at the top of the lid 32, which closes the cup-shaped container 22, to a second port 64, which may be injection-molded, for example, to the top of the tank cap 18 in spigot shape. The vent line 60 is preferably made of a reducing agent-resistant material, preferably made of a flexible elastomeric material or thermoplastic. Through the vent line 60, the air space 50 is connected above the level 28 of reducing agent 12 in the cup-shaped container 22 with the air space 48 in the storage tank 10 below the tank cap 18, i. vented into these. The air space 48 in turn is at the top of the tank lid 18, a vent or vent line 72, which is formed nozzle-shaped, assigned and closed by a spider 74. The ventilation line 72 comprises a tablet-shaped venting element 42, which is enclosed by the third pin 70 fixed in this, and which is made of a water-repellent material having hydrophobic properties.

The illustration according to FIG. 3 shows that, starting from the lower region within the pot-shaped container 22, in which the heater 26 is located, the following air path 66 is set: owing to the fact that the suction lance 24 extending through the cup-shaped container 22 extends, is a heatable suction lance, an adjusting by heating air gap between the outside of the heated suction lance 24 and this enclosing solid cis-shaped phase 14 of the reducing agent supply 12 is formed. Thus, the liquid phase 16, which surrounds the heating element 26 and the air space 50 above the level 28 of the cup-shaped container 22 in a pressure equalization enabling connection with each other. According to the air path 66, the air space 50 is now connected to the air space 48 of the storage tank 10 below the tank cap 18, so that a joint ventilation of both air spaces, ie the air space 48 and the air space 50 via one and the same loading or Vent line 72, the In the embodiment according to FIG. 3, the storage tank 10 or its air space 48 is assigned.

Preferably, the lid 32, with which the cup-shaped container 22 is closed, made as a plastic injection molded component, so that advantageously both an opening for a return line 52 and the first port 62 can be molded onto this. The lid 32 for closing the pot-shaped container 22 is fastened by means of a cover screw 54 on an external thread 34 of the tank cap 18, which can also be represented in a simple manner when manufacturing the storage tank 10 as a plastic injection molded component.

A seal of the vent line 60 after plugging onto the first port 62 and the second port 64 of the tank cap 18 may e.g. be realized by a Christmas tree profiling of the first terminal 62 and the second terminal 64, as shown in Figure 4.

In a production of the storage tank 10 as an injection molding or in the blow molding of plastic material, the second port 64 and the third port 70, which serves to receive the nozzle 72 for ventilation or venting, can be molded onto the latter, which reduces the production costs favorably influenced and a large degree of freedom with respect to the tank geometry of the storage tank 10 allows.

Illustratively not shown in FIG. 3, it is possible to provide a watertight storage tank 10 by attaching to the third port 70 of the ventilation line 72 at the top of the tank cap 18 a hose of flexible material, e.g. Plastic material is connected, which extends into a permanent air space, so that at all times a ventilation of the air spaces 48, 50, which communicate with each other via the vent line 60, is ensured in the permanent air space. This possibility also exists in the embodiment variant according to FIG. 1 in that plastic hoses are in each case pushed onto the tank vent 36 and the pot vent 38 and thus a watertight system is created.

In the embodiment according to FIG. 3, a simplified design of the storage tank 10 results, be it capable of being watered, if it is designed for a non-watertight system. The venting element of the pot venting 38 is always designed to be smaller than the venting element 42 of the tank vent 36 or 72 for reasons of installation space and the volume to be vented. In the venting element 42, which is used in the tank vent 38 takes place a dimensioning on a larger air flow at ventilation.

Figure 4 shows a variant for the sealing of the ventilation / vent line.

To realize an effective seal between the vent line 60 and the ventilation and exhaust 72 between the terminals 62, 64 or a separate third port 70 on the cover of the storage tank 10, 70 sealing profiles 76 can be attached to the terminals 62, 64 and third terminal be, for example are designed as Christmas tree profiles. Three or more in the circumferential direction around the end of the terminals 62, 64 and 70 respectively extending annular sections engage in the material of the vent line 60 and a vent hose 60 or the ventilation or venting line 72 extending from the storage tank 10 in the vertical direction extends, a.

The illustration according to FIG. 5 shows a watertight system with a ventilation system which extends through a wet room into a drying room.

As is apparent from the illustration of Figure 5, the ventilation of the air space 50 in the cup-shaped container 22 via the vent line 60. This extends from the first port 62 above the air space 50 in the pot-shaped container 22 to the second port 64, which is connected to the air space 48 in the storage tank 10. From the air space 48 in the storage tank 10, the ventilation line 72 extends substantially in the vertical direction. As can be seen from the illustration according to FIG. 5, it is to be ensured in watermatable systems that the air space 48 in the storage tank 10 is always in communication with the environment. If the entire system is located in the wet space 80, ie below a reference level 84, then it must be ensured that the ventilation line 72 with the ventilation elements 42 held thereon safely extends into a drying space 82, so that there is always an air-conducting connection between the air space 48 is ensured in the storage tank 10 and the environment. Depending on the permissible wading depth of the vehicle, also from depends on other parameters, the length of the ventilation line 72 is interpreted.

The remaining components of the illustration according to FIG. 5 can essentially be taken from the embodiment variant according to FIG. In the embodiment variant shown in FIG. 5, the pot-shaped container 22 is embedded in the storage tank 10. However, it is also possible to design variants in which the cup-shaped container 22 is arranged spatially separated from the storage tank 10, wherein the cup-shaped container 22 and the storage tank 10 can be connected via the hose-shaped vent line 60 in conjunction. From the storage tank 10 then extends, as shown in the illustration of Figure 5, a ventilation line 72 in the drying room 82, depending on whether it is a watfähiges or a non-watertiges system. FIG. 5 also shows that the heater 26 is mounted at the lower end of the heated suction lance 24 above the tank bottom 20 of the storage tank 10. Due to the heated suction lance 24 forms around these the liquid phase 16, which in turn from the solid phase 14, i. the frozen reductant supply 12 is enclosed.

The air dream above the cup-shaped container 22 is indicated by reference numeral 50. Analogous to the illustration according to FIG. 3, the overflow opening 40 between the storage tank 10 and the cup-shaped container 22 is located in the wall of the cup-shaped container 22. The tank lid 18 is identified by reference numeral 18 analogously to the illustration in FIG.

Claims

claims 1 . Storage tank (10) for receiving a freezable medium (12), in particular a reducing agent, with at least one ventilation / venting line (34, 36, 72) and a cup-shaped container (22) embedded in the storage tank (10), characterized in that an air space (50) in the pot-shaped container (22) via a vent line (60) or an overflow opening (40) with an air space (48) of the storage tank (10) is in communication via the at least one ventilation / discharge line (34, 36, 72) is ventilated. 2. storage tank (10) for receiving a freezable medium, characterized in that in the cup-shaped container (22) has a heater (26) is received and surrounded by the reducing agent (12), heated suction lance (24) through the cup-shaped container (22 ). 3. storage tank (10) according to claim 1, characterized in that the vent line (60) is made of a reductant-resistant elastomer. 4. storage tank (10) according to claim 1, characterized in that the vent line (60) from a first port (62) of a lid (32) of the cup-shaped container (22) to a second port (64) of a tank cap (18) of the reservoir (10). 5. Storage tank (10) according to claim 4, characterized in that the first connection (62), the second connection (64) and a further connection (70) for receiving the ventilation / venting line (72) to the tank cover (18). or the storage tank (10) are molded. 6. storage tank (10) according to claim 4, characterized in that the vent line (60) at the terminals (62, 64) via sealing profiles (76), in particular Christmas tree profiles, is sealed. 7. storage tank (10) according to claim 1, characterized in that the air space (48) and the air space (50) via respective separate ventilation / discharge lines (34, 36) are aerated and vented. 8. storage tank (10) according to claim 1, characterized in that the storage tank (10) and the cup-shaped container (22) are arranged spatially separated from each other and the cup-shaped container (22) via the vent line (60) through the storage tank (10). ventilated. 9. storage tank (10) according to claim 7, characterized in that the loading or  Venting line (34, 36, 72) for representing the wetting capability comprises at least one flexible hose extending through a wet room (80) in a drying space (82). 10. storage tank (10) according to claim 1, characterized in that the ventilation / discharge lines (34, 36) each comprise a tablet-shaped venting element (42).