PRINCIPLES OF OPERATION 1
AQUATECH OPERATIONS, SERVICE AND PARTS MANUAL
A Product of Hi-Vac Corporation
PRINCIPLES OF OPERATION
POSITIVE DISPLACEMENT EXHAUSTER AND WATER PUMP UNITS
This machine is a combination vacuum and high pressure water unit for excavation of soil.
The vacuum pump is a rotary lobe, positive displacement exhauster. During operation of the
vacuum system, material is picked up at the end of the suction line and pneumatically conveyed
through the intake tubes, the boom hose, and to the debris tank. As the material enters the larger
area of the debris tank the velocity of the air flow is reduced and the material drops out of the air
stream, settling at the bottom of the tank. The spent air flows through the ball check valve, and
through a metal screen in the centrifugal scrubber externally located at the front of the body and
though a final screen at the blower inlet. At this point the filtered air flow enters the exhauster
and is expelled through a silencer/muffler to the atmosphere.
A positive displacement triplex plunger water pump provides the water pressure and water flow to
the hydro excavation nozzle attached to the end of the handgun or lance.
In the water system, the water flows from the water tanks, mounted outboard of the debris
tank, through a crossover manifold, through the water pump feed line, into the suction side of
the pump. The pressurized water is then pumped forward to the water control valve and routed,
depending on the position of the valve, either to the hose reel for hydro excavation, or by return
lines to the water tank. The vacuum and water system can be used simultaneously when excavat
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ing soil. This allows conveyance of flushed out materials and water into the debris tank.
CONTROLS AND GAUGES
It is important for the operator to fully familiarize him/herself with the location, appearance and
function of the various controls and gauges on any new X-VAC Hydro Excavator. Please read this
section carefully, and refer to it whenever any section of the manual describes a control which you
cannot identify.
Several controls are mounted in the chassis cab itself. These controls allow the operator to engage and
disengage the water pump, exhauster, and hydraulic system. In addition, a main power
indicator light and switch, and a low water warning light and switch are among the standard controls in
the chassis cab. The water pump and exhauster are engaged and disengaged by electro-pneumatic
solenoid valves. These solenoids are operated by electric toggle switches in the cab. Because each
manufacturer will have a different cab layout, even among models of the same manufacturer, our
description of their location is general. In addition there is a switch that controls the “ON/OFF”
function of the water heater and compartment heater.
POWER DECK SYSTEMS ENGAGEMENT
Before engaging any of the power systems on this vehicle, you must first determine that there is at
least 120 psi in the air brake system. Check the air pressure gauges on the dashboard to confirm this.
The PTO is actuated by means of electro-pneumatic solenoid valves. While engaging PTO systems using
the switches described in the following paragraphs, the vehicle transmission must be put into neutral
and the parking brakes set. For vehicles with standard transmissions, the clutch must be depressed as
well.
Caution!
The transmission should never be operated in a gear range greater than indicated on
either the dashboard label or unit identification sheet.
Failure to heed this caution may result in severe damage to the water pump or
exhauster.
Please consult with the factory if the vehicle gear range is not specified.
