DE10010250A1 - Device to produce a salt mist used in salt testing chambers for testing the corrosion resistance of automobile prototypes comprises a pressurized air feed line, a suction line, an atomizing nozzle, and a moistening unit - Google Patents

Abstract

Device to produce a salt mist comprises a pressurized air feed line (23); a suction line (16) connected to a salt water vessel (14); an atomizing nozzle connected to the outlet (18) of the pressurized air feed line; and a moistening unit (24) arranged in the pressurized air line. Independent claims are also included for: (a) salt testing chambers; and (b) a process for producing a salt mist. Preferred Features: The moistening unit additionally contains devices for heating the pressurized air introduced.

Description

The invention relates to a device for generating salt spray for a Salt test chamber, such a salt test chamber and a method for producing Salt spray.

In order to be able to test the corrosion resistance of automotive prototypes this for a specified period of a defined salt spray atmosphere exposed. If necessary, elevated temperatures can also be set become. To maintain a salt spray atmosphere of the desired Composition you need devices for generating such salt spray, which in the salt test chamber, in which the entire corrosion protection test is to be installed.

The object of the present invention was to be as simple as possible and at the same time reliable device and a method for generating salt spray for a To provide salt test chamber.

This object is achieved by a device according to claim 1, which contains the following elements:

• a) a compressed air supply line, via which the device compressed air or generally a suitable gas under atmospheric pressure increased pressure can be supplied;
• b) a suction line, the entrance of which is connected to a salt water vessel, so that, if the salt water container is filled with salt water and a vacuum in the Suction line prevails, salt water is sucked out of the salt water vessel;
• c) at least one atomizer nozzle, which is connected to the outlet of the compressed air supply line and is connected to the output of the suction line and in which via  Compressed air salt water is sucked out of the salt water container and atomized can;
• d) a humidification unit, which is arranged in the compressed air line, so that compressed air conducted through the compressed air line can be enriched with moisture can.

With the device mentioned, a salt spray atmosphere can be efficiently produced generated by salt water stored in the salt water vessel with the aid of the Compressed air is divided into microscopic droplets through the atomizing nozzle. Since the Distribution process of the salt water is done with the help of compressed air, it is does not require the salt water to rise in the temperature range Bring evaporation temperature. It is also advantageous that the atomization Compressed air used in the humidification unit can be moistened so that it not like with untreated compressed air to a drying effect during the expansion of the Compressed air comes in the atomizing nozzle. This ensures that Salt water is essentially broken down into microscopic droplets of fog, which the have preset salt concentration. So it doesn't come because of one uncontrolled drying effect for a partial withdrawal of water molecules and a corresponding concentration of the salt in the remaining ones Drops of fog.

The humidification unit can, according to claim 2, additionally have means for heating the contained compressed air. With these, the temperature of the compressed air can be increased a desired value can be set. In particular, this can be the value which one should be maintained in the salt test chamber or which one defined amount is above this temperature. This can ensure that the compressed air introduced into the salt test chamber is the same after its expansion Temperature as the prevailing atmosphere there, so that it does not interfere of the temperature level in the chamber.

In a special embodiment of the humidification unit according to claim 3 this consists of a bubble column with an inlet for compressed air at the lower end and one Outlet for compressed air at the top. Such a bubble column can be filled with liquid such as deionized water, so that the passed through  Compressed air is split into bubbles and on its way from the bottom to the top End of the bladder column absorbs liquid. Through a transparent construction of the Bladder column can be visual control at the same time, which Faults in the flow of compressed air or in the filling of the humidification unit immediately reveals.

It can be according to claim 4, the bladder column with a level controller for Filling liquid to be connected, which ensures that a predetermined desired Level in the bladder column is maintained. The amount of liquid filling in The bubble column determines the length of the path that the compressed air takes through the Must put liquid back. It is therefore also decisive for the amount of Liquid that can be absorbed in this way. To defined and to be able to maintain reproducible conditions in the salt test chamber therefore, maintaining a constant level in the bladder column is important. This applies to more so than by absorbing liquid through the compressed air of the bladder column fluid is constantly withdrawn.

Furthermore, according to claim 5, the bubble column can contain a regulated heating. Such a heating makes it possible to fill the bubble column with a filling liquid maintain certain temperature. In the bladder column, in addition to Humidification also take place a heating of the passed compressed air. Farther the heating supports the evaporation of the filling liquid, i.e. the Enrichment of the compressed air with moisture.

In another development of the device according to the invention according to claim 6 this contains at least one distribution line into which the outlet of the Atomizer nozzle (or the outlet of the atomizer nozzle) opens. The distribution line ensures that the salt spray generated by the atomizer nozzle on one desired and optimal location in the salt test chamber is given. In particular can be ensured with the distribution line that the release of the salt spray distributed over a larger area and thus does not take place in a punctiform manner, such as it would be the case if it emerged directly from the atomizer nozzle. That way ensures that the salt spray atmosphere in the salt test chamber is as large as possible is homogeneous.  

In order to protect the atomizer nozzle from contamination according to claim 7 in the Suction line a filter can be arranged.

For the salt water vessel there is the possibility according to claim 8, this as Form columnar vessel, which via circulation lines with a storage tank connected is. By arranging such a column vessel in the Salt test chamber can ensure that the salt water in it Ambient temperature of the salt test chamber assumes. Furthermore, can Circulation pipes take a constant pumping over the salt water, so that this has the desired salt concentration homogeneously. This salt concentration can be checked centrally in a storage tank where the removed one is Amount of salt water can be refilled.

The invention further relates to a salt test chamber according to claim 9, which at least one, but preferably six to eight devices of the above contains described type for the production of salt spray. Such Salt test chamber allows for a relatively low installation effort Maintaining a defined salt spray atmosphere. By arranging one corresponding number of devices for generating salt spray can Suitable power levels must be installed for each salt test chamber size.

In the salt test chamber according to claim 10, the salt water vessels Atomizing devices by substantially vertically aligned and in essentially formed tubes extending over the wall height of the salt test chamber. Such pipes have the advantage that a salt water column forms in which the salt water can essentially come to rest and in the heavier Can sell components. Furthermore, the large surface of the pipes ensures that the temperature of the salt water in the pipes of the Adjusts the ambient temperature in the salt test chamber.

Preferably, the salt test chamber according to claim 11 contains horizontally Pipes running along the ceiling with outlet slots, which serve as distribution lines for the salt spray generated by the atomizers. Such pipes ensure that the salt spray from the highest point of the salt test chamber over a larger one Line or area are distributed. A punctual delivery  with corresponding inhomogeneities in the resulting salt concentration avoided.

The salt test chamber may further include underfloor heating. With this, the temperature in the salt test chamber can be safely and efficiently on one maintain the desired level.

The invention further relates to a method according to claim 13 for generating Salt mist, in which compressed air is passed through an atomizing nozzle and thereby Salt water is sucked in and atomized, the process being the Compressed air is moistened before being introduced into the atomizer nozzle. Through the Humidification of the compressed air can be prevented when the compressed air expands a drying effect occurs, which leads to uncontrolled changes in the Salt concentration of the resulting salt spray would lead.

Furthermore, according to claim 14, the compressed air is preferably introduced into the Atomizer nozzle warmed up. In particular, it can depend on the temperature of the Salt test chamber are brought up to a value above, so that they after its expansion has the temperature of the salt test chamber. Uncontrolled Changes in temperature caused by the introduction of compressed air are avoided.

The temperature of the heated compressed air and / or the atomized salt water to 15 ° C to 30 ° C, preferably set to 20 ° C.

The atomized salt water preferably contains a concentration according to claim 16 of 5 weight percent sodium chloride (NaCl).

The salt spray is preferably dispensed according to claim 17 so that it with a Speed of 0.1 mm / h to 20 mm / h, preferably 0.3 mm / h to 10 mm / h, falls particularly preferably with 1 mm / h to 2 mm / h.

The invention further relates to a method according to claim 18 for carrying out a Salt spray tests on automobiles, which is characterized in that the salt spray can be generated with a method of the type explained above. According to  Claim 19 preferably devices of the type mentioned above for generating the Salt spray used.

Furthermore, in the method according to the invention according to claim 20 advantageously a negative pressure in the interior of the vehicle to be tested the atmosphere in the salt test chamber, which causes the salt spray the ambient atmosphere also in hidden cavities of the vehicle can penetrate. The advantages of this vacuum process can of course also be used if the salt spray in a way other than the one described above be generated.

In the following the invention is explained by way of example with the aid of the figures. Show it:

Figure 1 is a perspective view of a salt test chamber with the supply systems for the production of salt spray.

Fig. 2 is a plan view of a device for generating salt spray with two atomizing nozzles.

A salt test chamber 20 is shown schematically in FIG. 1, in which corrosion tests of automobile prototypes can be carried out. For this purpose, a test vehicle (not shown) is introduced into the salt test chamber 20 for a certain period of time and there exposed to a salt spray atmosphere of a defined concentration and temperature. The salt mist is generated by devices 10 according to the invention, of which three devices are arranged on the long sides of the ceiling edges of the salt test chamber in the case shown.

A single device 10 for generating salt mists consists of a T-shaped construction, which is explained below with the aid of FIG. 2. First of all, the device has a pipe 14 , which runs vertically from the bottom of the salt test chamber to the ceiling, which can be, for example, a 3 "PVC pipe. In the vertical pipe 14 there is a salt water column during operation of the device, which is through an inlet 21 at the lower end An overflow 22 at the upper end of the tube directs excess salt water back to a storage and mixing tank 26 .

The end of a suction pipe 16 , which runs vertically upwards and opens into a T-connector 13 , dips into the salt water level. Via the T-connector, the suction line 16 is continued horizontally with lines in two opposite directions, which open into two atomizing nozzles 17 . At the lower end of the suction line 16 , a filter 15 is arranged, through which salt water sucked into the suction pipe is passed in order to be cleaned.

The atomizing nozzles 17 have a connection 18 for the supply of compressed air. With the help of this compressed air, which flows out of the nozzles, a negative pressure is generated in the suction line 16 , which leads to the suction of the salt water. The salt water thus entering the atomizing nozzle 17 is atomized there by the compressed air into fine mist droplets. Atomizer nozzles of this type are available, for example, from Atotech USA Inc., Strongsville, Ohio, USA.

The salt spray generated is sprayed horizontally on both sides by the two atomizing nozzles 17 . It arrives in a horizontal distributor pipe 11 on the right and left side of the device. The distributor pipes 11 together with the pipe 14 form a T-shaped construction. Like the pipe 14 , the distribution pipes 11 can be produced from a 3 "PVC pipe. Slots 12 of typically 19 × 600 mm are embedded in the distribution pipes, through which the salt spray is distributed over a large distance to the salt test chamber.

A total of six T-shaped devices 10 for generating the salt spray can be seen in FIG. 1, the distributor lines 11 running parallel to the upper edge of the ceiling of the salt test chamber 20 . It can also be seen that the salt water pipes 14 are connected at their lower end to a feed line 21 for fresh salt water. This feed line is filled with salt water from a mixing and storage tank 26 by means of a pump 27 . Furthermore, it can be seen that the salt water pipes 14 are connected at their upper end to a return line 22 for overflowing salt water, which leads back to the mixing and storage tank 26 . This creates a closed cycle in which salt water is constantly pumped around. The desired salt concentration, which is typically 5% by weight NaCl, is monitored and, if necessary, readjusted in the mixing and storage tank.

Furthermore, supply lines 23 for compressed air can be seen in FIG. 1, which lead to the T-shaped devices 10 with the atomizing nozzles 17 and supply the latter with compressed air. The compressed air lines 23 on the two sides of the salt test chamber are each guided separately through a humidification station 24 before they open into a common inlet 28 for compressed air. A compressed air line 29 is also branched off from the common inlet mentioned, which leads to the mixing and storage tank 26 and ensures movement and mixing of the filling liquid there.

The humidification stations are bubble columns 30 which are filled with deionized water. The compressed air introduced at the lower end of the bubble column rises in bubbles through the water and leaves the bubble column at the upper end again through the compressed air line 23 connected there. On its way through the water, the compressed air absorbs moisture and thus reaches the atomizing nozzles 17 moistened. Drying effects on the spray nozzles from untreated compressed air are therefore avoided. The bubble columns are made, for example, from a brass base plate, a cover from CPVC (chlorinated PVC) and a transparent 8 "PVC tube. The level control unit is made from a 14" PVC tube and 1¼ "end and middle plates.

The level of the water in the bubble columns is monitored by a level control unit. This is connected via lines to a reservoir 25 for deionized water, from which water can be removed and refilled if necessary.

The humidification stations also contain a heater with which the contained Water and thus the compressed air passed through can be heated. Typically a heating element with an output of approx. 1 kW is used for this.

The pressure within the bubble columns is adjusted to approximately 1.03 bar (15 psi). The temperature of the fill water is approx. 33 ° C (118 ° F). For safety reasons, pressure relief valves are installed on the columns 30 .

When performing corrosion tests on automobiles, it is important that in the Salt test chamber maintains a defined temperature of typically 20 ° C (95 ° F) is obtained. To ensure this, the salt test chamber is equipped with a Underfloor heating provided. Plastic tubes are used to protect against corrosion (19 mm diameter) laid in the floor. The heating is done with heating water a temperature of approx. 50 ° C to 60 ° C.  

REFERENCE SIGN LIST

10th

contraption

11

Distribution line

12th

Outlet slot

13

T-connector

14

Salt water container

15

filter

16

Suction line

17th

Atomizer nozzle

18th

output

20th

Salt test chamber

21

Intake

22

Overflow

23

Compressed air supply

24th

Bubble column

25th

Level control

26

Storage and mixing tank

27

pump

28

inlet

30th

Bubble column

Claims (20)

1. Device for generating salt mists for a salt test chamber ( 20 ) containing

• a) a compressed air supply line ( 23 ),
• b) a suction line ( 16 ), the input of which is connected to a salt water vessel ( 14 ),
• c) at least one atomizing nozzle ( 17 ) which is connected to the outlet ( 18 ) of the compressed air supply line and the outlet of the suction line and in which salt water can be sucked in and atomized from the salt water vessel via compressed air supplied,
• d) a humidification unit ( 24 ) which is arranged in the compressed air line.

2. Device according to claim 1, characterized in that the humidification unit ( 24 ) additionally contains means for heating the passed compressed air. 3. Device according to one of claims 1 or 2, characterized in that the humidification unit consists of a bubble column ( 24 ) with an inlet for compressed air at the lower end and an outlet for compressed air at the upper end. 4. The device according to claim 3, characterized in that the bubble column ( 24 ) is connected to a level controller ( 25 ) for the filling liquid. 5. The device according to claim 3 or 4, characterized in that the bubble column ( 24 ) contains a controlled heating. 6. Device according to one of claims 1 to 5, characterized in that it contains at least one distributor line ( 11 ) into which the outlet of the atomizer nozzle ( 17 ) opens. 7. Device according to one of claims 1 to 6, characterized in that a filter ( 15 ) is arranged in the suction line ( 16 ). 8. Device according to one of claims 1 to 7, characterized in that the salt water vessel is a column vessel ( 14 ) which is connected via circulation lines ( 21 , 22 ) to a storage tank ( 26 ). 9. salt test chamber ( 20 ), characterized in that it contains at least one, preferably four to eight devices according to one of claims 1 to 8. 10. Salt test chamber according to claim 9, characterized in that the salt water vessels are formed by tubes ( 14 ) extending substantially vertically over the wall height of the salt test chamber. 11. Salt test chamber according to claim 9 or 10, characterized in that it contains tubes ( 11 ) running horizontally in the ceiling area of the salt test chamber with outlet slots ( 12 ) as distribution lines. 12. Salt test chamber according to one of claims 9 to 11, characterized in that it contains underfloor heating. 13. A method for producing salt mist, in which compressed air is passed through an atomizing nozzle ( 17 ) and thereby sucks in and atomizes salt water, the compressed air being moistened beforehand. 14. The method according to claim 13, characterized in that the compressed air is warmed up. 15. The method according to claim 13 or 14, characterized in that the Temperature of the salt water and / or the heated compressed air 15 ° C to 25 ° C, is preferably 20 ° C. 16. The method according to any one of claims 13 to 15, characterized in that the salt water with 5 weight percent NaCl is used.   17. The method according to any one of claims 13 to 16, characterized in that the salt spray at a rate of 0.1 mm / h to 20 mm / h, preferably 0.3 mm / h to 10 mm / h, particularly preferably 1 mm / h to 2 mm / h. 18. A method for performing a salt spray test on an automobile, thereby characterized in that the salt spray with a method according to one of the Claims 13 to 17 are generated. 19. The method according to claim 18, characterized in that a device according to one of claims 1 to 12 is used to generate the salt spray. 20. The method according to claim 18 or 19, characterized in that inside a negative pressure is generated in the vehicle to be tested.