Johnston VM502, Руководство по обслуживанию

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V Range 502
l
652
l
802 Maintenance Manual
MA4:2
Chapter - Water System
General Description
The water systems can be categorised into three systems.
Low pressure:- For dust suppression and lubrication of consumable components.
High pressure:- (Supawash) For surface cleaning.
Re-circulation:- For reducing the overall usage of water and extended on station work time
Low Pressure Water
Pressure for the water supply is provided by a twin diaphragm pump hydraulically driven from the
auxiliary engine. Pressure regulation is by a relief valve situated at the rear of the machine. Filtration is
by two filters, one mounted within the water tank and a second in-line type located at the right hand rear
of the machine. An isolator valve is built into the in-line filter for ease of element servicing. All sweeping
spray jets are controlled by simple solenoid valves, manifold mounted within the systems locker.
Control of the Washdown hose and Wanderhose water injection is by manual valves at the rear of the
machine subframe.
Supawash
This optional equipment comprises a hydraulically driven high pressure water pump mounted within the
subframe, and a hand lance with a 15 metre hose wound onto a recoiling reel.
Front and nozzle spraybars are available as additional options.
Recriculating Water
This option enables the water held within the body to be drained to the suction nozzle, enabling it to be
re-used for lubrication and dust suppression.
Supawash Unloader Valve - Pressure Setting
1. Ensure that the hydraulic relief valve has been set as outlined in section 8.
2. Fit a hydraulic test gauge to the Supawash manifold (T13).
3. Disconnect the 3/8” bypass pipe at the unloader valve and plug the hose end.
4. Turn on the front spraybar tap.
5. Activate the Supawash and increase the engine speed to 2000 rpm. Check to see if any water
is leaking from the bypass port on the unloader, if not loosen the retaining nut on the top of the
unloader and unscrew anticlockwise until water dribbles from the bypass port. Gently turn the
adjuster clockwise until water stops dribbling, then turn the adjuster 1/2 turn clockwise and lock
off the retaining nut. The operational pressure at the manifold should be 100 bar nominal. If the
pressure is higher check again for blocked jets. If the pump operates at a pressure in excess of
100 bar there is a problem that will effect the life of the pump and invalidate any warranty.
NB - Do not turn off the front Supawash spraybar or water will be ejected from the bypass valve
where the hose has been removed.
6. Stop the engine and reconnect the bypass hose.
Circuit Pressures
Two test points are provided for checking the water pressures.
Test Point No. Function
W-1Z2 Dust Suppression Sweep System
W-12Z2 Supawash System
WATER SYSTEM - INTRODUCTION