CONDENSERS FOR COMPRESSED GAS SYSTEMS

Abstract: A condenser for a compressed air braking system has a check valve (13) in its output connection and a dump valve (22) which is signaled by a fluid pressure signal or an electrical sig­ nal for dumpinng the fluid pressure contained in the condenser where the air pressure at the output connection attains a set valve.

Description: Condensers for Compressed Gas Systems. This invention relates to condensers for compressed gas systems and relates more especially to condensers for condensing moisture from air on its way from an air compressor to a reservoir. In compressed air systems it is usual to connect a condenser between a reciprocating piston compressor and a reservoir to be charged. Such a condenser serves to cool the air which is warmed by the compression process and thereby condenses moisture therein before the air passes to the reservoir. A condenser also has the advantage of removing oil carried over from the compressor and thereby preventing it reaching the compressed air system which is supplied from the reservoir. Moisture and oil is removed from the condenser itself either by a manuly operable drain cock or by an automatic drain valve. Although an automatic drain valve is preferred it has the disadvantage of being relatively low capacity and may become clogged with emulsified oily water and carbon. This is particularly disadvantageous in applications such as compressed air braking systems where it is most important that such contaminants do not reach complex system valves to cause sticking or corrosion thereof. According to the invention, there is provided a condenser for a compressed gas system including a housing of thermally conducting material with an input port at an upper end and a baffle for directing flow of gas over the interior surface of the wall of the housing to an interior region which communicates with an output port, said output port being provided with a check valve for preventing reverse flow from a reservoir connected thereto and a drain-off port of the chamber being provided with a fluid pressure operable electrically operable dump valve which is intermittently operable to dump the air pressure from the said chamber. In order that the invention may be more clearly understood and readily carried into effect, the same will be further described by way of example with reference to the accompanying drawings the single figure of which, Fig. 1 illustrates one example of the condenser according to the Invention and Fig. 2 illustrates part of a compressed air system using the condensor of Fig. 1. Referring to Fig. 1 of the drawings, a cylindrical thermally conducting housing 1 has an upper open end which seals onto a downwardly projecting spigot 2 of an upper casting 3 the spigot 2 being provided with an '0' ring II the cylinder being retained in position on the upper casting by means of bolts which are now shown. The upper casting has ç compressed air input port 6 communicating with the outer surface of an invested cup-shaped baffle 7 which serves to direct compressed air from a compressor around the interior surface of the cylinder. The baffle 7 is retained, together with a cylindrical filter element 8 pressure input port 25 which communicates with the upper surface of piston 24 and can be provided with a control signal from the compressor unloader or the system governor. The output side of the valve 22 communicates with a simple rubber disc vent 26 of known form attached to the casting by screws such as 28. The casting is retained in contact with the-end of the cylinder by three retaining bolts such. as 27. In operation of the condenser, compressed air is supplied by the compressor to the port 6 and by virtue of the baffle 7 is caused to flow downwardly around the cooling interior surface of the cylindrical wall of the cylinder and emerges at the lower end into the inner region ?9. Condensed gravity water and oil droplets can flow-under/down the interior wall of the cylinder and run through scuppers 20 into the central part of the lower casting defined by the upstanding rim 19. Air in the inner chamber 29 thence flows radially inwardly through the cylindrical filter element 8, into the chamber 17 from whence it can flow out via check valve 13 to charge a reservoir connected at output port 14. The compressor will normally be provided with a governor either for controlling an unloader mechanism on the compresso itself or to provide operation of an unloader valve whereby the compressor continues to operate off-load and thereby ceases temporarily to supply further air to the reservoir once the reservoir pressure has attained a level set for the system. In use of the present condenser according to the invention, the unloader signal is connected disc valve member 30 and a spring 31 by means of a disc 9 and a retaining bolt 10 screwed into an internally threaded spigot 11. A suitable rubber gasket 12 is positioned between the baffle and the housing to normally prevent communication between the outside of the baffle and the interior of the region between the filter and an outlet port 14 other than round the lower edge of the baff and via the filter 8. Disc valve member 30 is spring loaded by the spring 31 to normally close off a filter bypass path via apertures 32 in disc 9 from the interior region 29 to the output region 17 but in the event of the filter becoming clogged the disc-valve may resiliently deflect to partially bypass the filter. The region 17 is connected to output port 14 which via a one-way check valve 13 which prevents the return flow of air from an air pressure reservoir when connected at 14. The lower end of the cylindrical housing 1 is provided with a closure casting 15 which bolted into an aperture 16 is sealed against the interior of the end of the cylinder by an '0' ring 18. The casting has an upwardly extending rim 19 provided with scuppers such as 20 for permitting condensed moisture and deposited oil to flow to the interi of the casting from where it can pass out via a drain passage 21. Threaded into the outward end of the casting 15 there is provided a dump valve assembly which consists of a normally closed valve member 22 spring loaded by a spring 23 and openable by the application of sufficient air pressure to the upper surface of a control piston 24. The casting is provided with a control to the port 25 whereby the piston 24 of the dump valve 22 is moved downwards to unseat the dump valve 22 and thereby permit substantial dumping of air pressure from the chamber 29 to drive out any condensed moisture, oily water or carbon mixture which has been deposited in the central part of the lower casting. By virtue of the check valve 13, no discharge of the reservoir takes place as a result of this dumping action. By the provision of a dump valve such as 22 in the lower end of. the cylinder of the condenser, an efficient clearing action is provided and problems such as may be encountered with a normal automatic drain valve are avoided. Furthermore, by designing the dump valve 22 to have a suitable capacity it can also operation in the system as an unloader valve for the compressor so that the need for a separate or integral unloader valve in the compressor cylinder head can be avoided. Such a system is shown in Fig. 2, having an air compressor 41, which for a vehicle compressed air system is driven by the engine of the vehicle. The output of the compressor is connected via a pipe 42 to the input port 6 of the condenser with check valve 13, the output 14 being connect by a branbh connector 43 to a multi-circuit protection valve for charging a plurality of reservoirs or circuit connected at pipes 44, 45, 46 and 47. A governor valve 48 of known form is connected between the branch connector 113 and the control input 25 of the dump valve of the condenser. In an alternative embodiment, the valve 22 may be an electrically operable valve, such as a magnet valve signalled electrically via a pressure operable switch provided in a governor such as 48 of Fig. 2.

Claims: CLAIMS 1. A condenser for a compressed gas system including a housing (1) of a thermally conducting material with an input port (6) at an upper end and a baffle (7) for directing the flow of incoming gas over the interior surface of the wall of the housing (1) to an interior region (29) which communicates with an output port (14), and with a drain valve (22) situated at the lower end of the housing for receiving condensed moisture characterised by the output port 14 of the condenser having a check valve 13 and by the drain valve (22) being part of a fluid pressure operable or electrically operable dump valve for dumping the pressure in said housing. 2. A condenser as claimed in claim 1 for a compressed air system characterised by the dump valve being of sufficient capacity to act as an unloader valve for a compressor connected to the input port. 3. A condenser for a compressed gas system sub stantiallyr-as described herein with reference to the accompanying drawings. 4. A compressed gas system characterised by a condenser (1) connected in a charging path (42, 14) between a com pressor 4 and a reservoir and including a governor (48) connected to sense the changed pressure of the reservoir to operate the dump valve.

Inventors: NEAL, BRIAN PATRICK, THOMAS, RICHARD, WALDRON, WILLIAM THOMAS
Applicants: BENDIX LIMITED
Application year: 1984
Main classification: B01D53
IPC codes: B01D53, B01D5