GB2103954A - An air drying arrangement - Google Patents

Abstract

An air drying arrangement for pneumatic systems, particularly compressed-air brake systems of motor vehicles, has two treatment chambers (31, 32) which contain drying medium. Inducted air is passed through the two treatment chambers alternatively to a service line of the pneumatic system for the delivery of dried air thereto and a portion of the dried air is diverted alternatively through the two treatment chambers for the purpose of regenerating the drying medium. In order to achieve a compact type of construction which requires only a small amount of installation space and in order to simplify maintainance and replacement, the two treatment chambers (31, 32) are disposed in a single container (1), and only a single cartridge (4) is used. The container (1) and the cartridge (4) are longitudinally divided into two parts by a multi-part partition (16, 30). <IMAGE>

Description

SPECIFICATION An air drying arrangement The invention relates to an air drying arrangement for pneumatic systems, and more particularly for motor vehicle compressed air brake systems.

A known air drying system, described in German published patent specification No.

2520307 has two containers which are disposed preferably parallel and adjacent to one another.

Each container is equipped with a cartridge which has to be exchanged after a time owing to ageing or soiling. For this reason, and as a result of any repairs which become necessary in the meantime, the containers have to be opened, an operation which involves considerable expenditure on labour. In addition to this, the known device is very bulky and takes up a large amount of installation space. Finally, it is complicated and expensive.

According to the present invention there is provided an air drying arrangement for a pneumatic system, the drying arrangement comprising a single container having two treatment chambers disposed therein which contain a regenerative drying medium for drying inducted air and which are alternately connectible to a service line of the pneumatic system for the delivery of dried air thereto, a portion of the dried flow of air being directed from the main flow of air alternately through the two treatment chambers for the purpose of regenerating the drying medium and then being exhausted to the atmospheric air.

In contrast to the prior art, the air drying arrangement of the present invention has the advantage that it is of very compact construction, so that it takes up only a small amount of installation space. Finally, it is advantageous that only a single container has to be put into operation during mounting or dismantling, and that only a single cartridge has to be changed, thus considerably facilitating manipulation and maintenance.

The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a sectioned side elevation of an air drier, Figure 2 is a cross section taken along the line Il-IlofFigure 1, and Figures 3 and 4 are two diagrams showing the flow paths in an air drying arrangement incorporating the air dryer of Figures 1 and 2.

An air drier has a cylindrical container 1 of hatshaped construction. A flat base plate 2 is fitted in the bottom edge of the container and is secured in the bottom edge in a manner which is not illustrated. A cylindrical cartridge 4 is clamped between the base plate 2 and an upper portion 3 of the container 1 to leave a cylindrical annular chamber 7, 7' between the outer surface 5 of the cartridge and an interior wall 6 of the container.

An annular seal 9 is fitted in an annular groove 8 in the inner side of the base plate 2. The base plate 2 is provided with two line connection ports 10 and 11 within the annular seal 9, a respective connection bush 12 or 13 being inserted into each of the ports 10 and 11. Furthermore, the base plate 2 has two further line connection ports 14 and 15 which lead to the annular chamber 7, 7'.

A diametrically extending transverse wall portion 16 is provided on the upper portion 3 of the container 1 in the interior thereof, a sealing strip 17 being fitted in the transverse wall portion 16. Furthermore, two springs 18 and 19 are provided on the upper portion 3. Finally, two axially parallel, diametrically opposite transverse wall portions 20 and 21 are provided in the interior of the container 1, sealing strips 22 and 23 also being fitted in the transverse wall portions 20 and 21 respectively (Figure 2). Alternatively, however, it is possible to injection mould the sealing strips 1 7, 22 and 23 onto the cartridge 4.

The cartridge 4 has a cylindrical outer wall made from plastics material which is impermeable to air. The cartridge 4 is filled with an absorbent drying agent 25 and is sealed towards the outside by a cover 26 which is permeable to air and a base 27 which is also permeable to air. A circular linttype filter 28 or 29 respectively is provided on the inside of the cover 26 and on the inside of the base 27.

The cartridge 4 has a partition 30 by which the cartridge is divided longitudinally into two cylinder halves. The partition 30 is a wall portion which, together with the transverse wall portion 1 6 and the transverse wall portions 20 and 21 and the sealing strips 17, 22 and 23, form a longitudinally extending partition 16, 20, 21, 30 which divides the container 1 and the cartridge 4 into two half annular chambers 7 and 7' and into two treatment chambers 31 and 32, the two annular chamber halves 7 and 7' and the treatment chambers 31 and 32 being disposed parallel and adjacent to one another.

In this manner, it is possible to service the two chambers 31 and 32 simultaneously by exchanging the single cartridge 4.

The mode of operation of the air drier will now be described with reference to the diagrams of Figures 3 and 4.

The humid air, delivered into a compressed air system by a compressor 43, flows through the line connection port 14 into the air drier where it passes through one half 7 of the annular chamber 7, 7'.

A certain portion of the atmospheric moisture condenses. The air then flows into the left hand half of the cartridge 4 from above, that is to say, into the treatment chamber 31, passes through the lint-type filter 28 where oil carbon or the like is separated, and then through the drying agent 25 where the atmospheric moisture is absorbed.

Finally, the air flows through a further lint-type filter 29 which prevents the air from entraining dust or particles from the drying agent into the line system.

The dried air enters the line connection port 10 at the bottom end of the treatment chamber 31 and then flows into a conduit 33 which leads to a solenoid-operated multi-position valve 34. A line connection 35, leading to a brake system (not illustrated), is provided downstream of the valve 34. Approximately 10% of the quantity of dried air is diverted by way of a throttle 36 and is fed into a line 37 leading to the line connection port 11.

This component flow flows through the right hand treatment chamber 32, that is to say, the right hand half of the cartridge 4. Since this air has expanded to atmospheric pressure by way of the throttle 36, it regenerates, in the countenflow, the drying agent 25 charged with moisture in the preceding cycle.

The air enriched with moisture then flows out of the cartridge 4 at the top end of the right hand treatment chamber 32 and flows through the half annular chamber 7' to the line connection port 15 and then into a line 38 which leads to an exhaust 39 by way of the multi-position valve 34.

The change-over is performed by a timing element 40 by way of the valve 34 after a predetermined period of time (change-over time) which can lie between 30 seconds and 2 minutes and which depends upon the drop in the point of condensation required by the air drier, the quantity of drying agent and the quantity of regeneration air flowing off by way of the throttle 36.

After the change-over has been effected, the right hand treatment chamber 32 undertakes the air-drying operation, and the left hand treatment chamber 31 is regenerated (Figure 4), that is to say, the air flows into half annular chamber 7' by way of connection 15, through treatment chamber 32 and out through connection 11 and into the line system by way of the multi-position valve 34.

A component of the dry air is diverted through the throttle and into treatment chamber 31 , where the drying agent is regenerated, and the air exhausted by way of half annular chamber 7 and line 14 leading to exhaust. After a predetermined period of time, determined by timing element 40, the valve 34 is changed over, and the first stage of the cycle is repeated.

Claims (11)

1. An air drying arrangement for a pneumatic system, the drying arrangement comprising a single container having two treatment chambers disposed therein which contain a regenerative drying medium for drying inducted air and which are alternatively connectible to a service line of the pneumatic system for the delivery of dried air thereto, a portion of the dried flow of air being diverted from the main flow of air alternately through the two treatment chambers for the purpose of regenerating the drying medium and then being exhausted to the atmospheric air.

2. An air drying arrangement as claimed in claim 1, in which the two treatment chambers are disposed parallel and adjacent to one another in the container.

3. An air drying arrangement as claimed in claim 1 or 2, in which the single container has disposed therein only a single cartridge accommodating the drying agent, for the two treatment chambers.

4. An air drying arrangement as claimed in claim 3, in which both the containers are cylindrical.

5. An air drying arrangement as claimed in claims 3 or 4 in which the container and cartridge are divided longitudinally into two symmetrical halves by partition portions which are in alignment with one another.

6. An air drying arrangement as claimed in claim 4 in which the cartridge is divided by a longitudinally extending wall portion into two half cylinders.

7. An air drying arrangement as claimed in claim 5 or 6 in which two axially parallel, diametrically opposite wall portions, serving as partition portions are disposed within the container and carry respective sealing strips which co-operate sealingly with the cartridge to define two half annular chambers in the container.

8. An air drying arrangement as claimed in claim 5. 6 or 7 in which a diametrically extending transverse wall portion, serving as a partition portion, is provided internally on a cover of the container and carries a sealing strip.

9. An air drying arrangement as claimed in claim 8 when appendant to claim 6 in which the sealing strip of the diametrically extending wall portion co-operates with an axial end of the longitudinally extending wall portion of the cartridge.

10. An air drying arrangement as claimed in any one of claims 5 to 9, in which inlet and outlet connections are provided in pairs on the container for each half.

11. An air drying arrangement constructed and arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.