Contracor BRS-5 [10/88] Mechanism

CONTRACOR

Version 2.0

2.3 Mechanism.

Compressed air is fed from the compressor to the pneumatic unit (1). Air is fed continuously

from the pneumatic unit (1) into the pressure vessel (8) and to the remote-control handle (2).

A solenoid pulse cut-off valve with a timer (9) is installed on the pressure vessel (8), which is

designed to feed air briey at regular time intervals to the lter (12) in the lter chamber (6)

in order to shake it and clear dust deposits. The remote-control handle (2) in its normal (not

pressed) state vents the air fed to it into the atmosphere, and in its pressed state feeds the air

rst to the solenoid safety valve and then to the proportioning valve of the pneumatic unit (1).

When the machine is switched on (by turning the knife switch and pressing the green button

on the panel of the electric box (13)), power is supplied to the solenoid safety valve and the

electric vacuum pump (3). The solenoid safety valve opens. The vacuum pump (3) creates

negative pressure in the lter chamber (6), cyclone separator (5) and in the working cavity of

the vacuum head (4).

The solenoid safety valve does not allow abrasive blast cleaning of a working surface while

the vacuum pump (3) is switched off.

When the button on the remote-control handle (2) (after turning on the apparatus) is pressed,

air enters the proportioning valve of the pneumatic unit (1), opening it and allowing a ow of

compressed air to pass from the compressor into the blast machine (7). Downstream of the

proportioning valve, air enters the discharge valve (10), opening it in the process.

Air supplied to the blast machine (7) (when the discharge valve is closed) causes its hermetic

sealing: the tank’s cut-off valve rises and cuts off the tank’s internal space from the internal

space of the cyclone. The tank pressure rises to the value set by the operator using the

pressure regulator and manometer on the electric box panel (13). Excess pressure in the

blast machine (7) causes the abrasive, lled beforehand into the tank through the door of the

cyclone separator (5), to pass together with the compressed air through the blast hose to the

vacuum head (4) nozzle.

In this way, a blast mixture of air and abrasive leaves the nozzle for treating the working

surface. Owing to the negative pressure, abrasive and dirt particles rebounding off the

surface enter the cyclone separator (5). In the cyclone separator (5), heavier particles lose

their kinetic energy and fall down through a screen (for separating out large dirt particles)

towards the cut-off valve of the blast machine (7) in order to enter the blast machine (7) again

when it is depressurised. In this way, the abrasive is used cyclically. Lighter particles pass

through the cyclone separator (5) into the lter chamber (6), where they are caught by the

lter (12). The heavier particles that have passed into the lter chamber fall downwards and

accumulate in the dust collector (11).

When the surface blasting is completed, the operator removes his/her hand from the remote-

control handle (2). The proportioning valve of the pneumatic unit (1) closes. The main ow of