This invention relates to the air processing unit for the air brake system of a motor vehicle.
An air processing unit in which a condensate separator and a turbo cut-off valve are integrated is described. The condensate separator prevents contamination of the desiccant used for air drying, thereby prolonging its field life. When the compressor intake is from the turbo-charger of the vehicle, and the air processing unit is unloaded, the turbo cut-ff valve prevents loss of turbo-charged air to the atmosphere. This improves the efficiency of the engine.
Such air processing units with air drying function performed by a desiccant and system pressure control performed by an integrated pressure regulator are known to the art. The condensate separator works on the principle of centrifugal separation of fluid droplets and removes almost all the condensed water and oil particles.
When the compressor of the motor vehicle is charged with air from the turbocharger of the engine which is a common industry practice to increase the air delivery from the compressor, and the pressure regulator unloads the unit, turbocharged air can be lost to the atmosphere. Such loss of turbocharged air from the engine intake system can result in a loss of efficiency of the engine. A turbo cut-off valve is integrated into the air processing unit to prevent such loss of turbocharged air.
Centrifugal condensate separators are known to the art. However prior art devices are
separate devices which are fitted in the upstream of the air processing unit. This
increases the cost of the system.
In this invention, a highly efficient condensate separator has been integrated into the air
processing unit, resulting in a compact and cost effective product.
The integrated turbo cut off valve works in conjunction with the condensate separator
components in preventing the loss of turbo charged air to the engine during the
unloading phase.
This invention will now be described with reference to the accompanying drawings
which illustrate, by way of example, and not by way of limitation, an embodiment of this
invention,
Figure 1 showing the sectional view through the embodiment

Figure 2 showing a partial view of the embodiment with compressed air being charged
into the system
Figure 3 showing a partial view of the embodiment in the unloaded condition.
Referring to figure 1, the main aluminium body casting A houses the deslccant cartridge B, which is retained through the steel housing C, the spring D, seal E and retainer plate F. The main body A has two ports, inlet port from the compressor A1 and delivery port to the downstream devices A2. The baffle G with helical fins G'. the turbo cut-off piston H, inner housing I, upper housing J, lower housing M, the untoader plunger K, spring K' and the unloader valve L constitute the condensate separator attached to the main body A.
It will be seen from figure 1 that the condensate separator baffle, the turbo cut-off piston and the untoader valve are arranged in a co-axial direction. This leads to a compact construction of this device. The coaxial arrangement of the turbo cut-off and unloader plunger facilitates a common signal path to operate both of them simultaneously. This reduces the complexity of manufacturing of the body A.
In prior art devices, the condensate separator consisting of a baffle, body and a purge valve (equivalent to unloader plunger K, spring K' and unloader valve L of the present invention) is a separate unit installed outside the main air processing unit. This increases the cost of the system. In said prior art devices, the turbo cut-off piston is also not concentric with the unloading or purging valve and the signal pressure to operate the turbo cut-off and unloader valve is conveyed through orifices in different directions, rendering the manufacturing of the device more complex.
Main body A also houses the non-return valve N and the pressure regulator O. The signal passage from the delivery port to the pressure regulator O is P, the delivery from the pressure regulator Q feeds to the signal passage R in the inner housing I, which in turn connects to the signal volume S between H and K.
When compressed air from the compressor enters the port A1, with the device in the charging position (system pressure below the set cut-out pressure in the pressure regulator 0), the air takes the path shown by the full arrows. The air enters the baffle, takes a helical path through the fins G'. enters the desiccant cartridge through the annular passage between the housing C and cartridge B, passes through the desiccant,

opens the non-return valve N and is delivered to the delivery port A2. In this condition, the signal path P is closed by the pressure regulator O. Therefore there is no signal pressure In the paths Q and R and in the signal volume S. The pressure of the inlet air above the turbo cut-off piston H keeps the piston against the bottom stop thus keeping the air flow path from inlet to delivery open. The unloading plunger K is kept pushed up by spring K', keeping the valve L closed. This position of the relevant parts during charging is shown in figure 2.
Figure 3 shows the relevant parts in the unloading position (system pressure reaches cut-out pressure of the regulator 0). The signal path P is opened by the pressure regulator O, admitting air to the signal paths Q, R and signal volume S, indicated by the dashed arrows. The pressure in signal volume S causes the unloading plunger K to move down compressing the spring K', thus opening the valve L, thus depressurising the device. The condensate collected in the inner housing I is drained to the atmosphere. At the same time pressure also acts under the turbo cut-off piston H, causing it to lift up and close the air path in the baffle G. This prevents the inlet port A1 from being directly connected with the atmosphere. This prevents loss of turbocharged air from the compressor delivery to the atmosphere, where the compressor intake air comes from the engine turbocharger.
It will be appreciated that various other embodiments are possible without departing from the scope and ambit of this invention.

We claim:
1. Air processing unit for the air brake system of a motor vehicle, comprising a
body housing a desiccant cartridge, a condensate separator baffle with
unloader plunger and valve assembly, said baffle being provided with a
helical air flow path, a turbo cut-off piston, a pressure regulator, the signal
paths from the said pressure regulator being connected to both the turbo
cut-off piston and the unloader plunger wherein the condensate separator
baffle, the turbo cut-off piston and the unloader plunger and valve assembly
are arranged coaxially facilitating a common signal path to operate both of
them simultaneously, with the said baffle and unloader plunger and valve
assembly compactly housed in the said body.
2. Air processing unit for the air brake system of a motor vehicle substantially
as herein described with reference to. and as illustrated in, the
accompanying drawings.