Pneumatic System; Fluid System; Temperature Control - Hartridge CRi-PC Operating And Servicing Manual

HARTRIDGE LIMITED
3.3

Pneumatic System

Refer to the Pneumatic Circuit diagram A129A702 at the end of this section.
The pneumatic circuit performs 4 functions:
1. Clamping the injector to be tested into the fixture. This uses the same principle as the
2. Metering unit return pressure. Air is supplied to the metering unit to create a
3. High pressure safety dump valve. Air is supplied through a separate regulator that is
3.4

Fluid System

Refer to the Hydraulic Circuit diagram A129A701 at the end of this section.
Test fluid is contained in a tank (nominal capacity 40 litres) in the base of the machine. The
tank contains an electric heater element controlled by the test stand computer and a level
switch to prevent a low fluid level exposing the heater element and causing a fire hazard. A
pump moves oil through a filter to the 'clean' tank (nominal capacity 3 litres). Test fluid is
sucked from the clean tank to the high pressure pump and the surplus returns to the main
tank. The clean tank contains a temperature sensor to measure and control the test fluid
temperature and another level switch to ensure the high pressure pump is not starved of test
fluid.
The Siemens high pressure pump is directly driven by a fixed speed electric motor, the
pressure to the rail and injector is set by a VCV (volume control valve) and a PCV (pressure
control valve) integral to the pump and controlled by the test stand control system.
By-pass flow from the high pressure pump passes through a water-to-oil plate heat exchanger
and cooled test fluid returns to the main tank. (Water flow is controlled by solenoid valve
when required).
NOTE Test fluid is only cooled when the high pressure pump is running.
The high pressure test fluid circuit is protected by a high pressure dump valve. A pressure
transducer measures the system pressure. The air pressure to the dump valve is set such
that if the pressure rises above 2100bar the valve is opened and high pressure test fluid is
dumped to the main tank. If the injector access door is opened a solenoid switches off the air
supply to the valve and the high pressure system is made safe for an operator to enter the
test area.
Injected test fluid passes from the injector, past a piezo transducer used to measure response
time to the delivery metering unit. The delivery metering unit is water cooled.
3.5

Temperature Control

The main temperature control system comprises a heater element and a water-to-oil heat
exchanger (on the pump spill flow) controlled by computer software via relays. The software
monitors the temperature via a sensor in the 'clean' tank connected to the CR pump control
board. The software switches on or off the heater and cooler by controlling relays on a
Programmable Logic Controller (PLC) to maintain the fluid temperature at the desired
setpoint.
NOTE:
HL037 (EN), Issue 13, AT714, 05/14
THIS IS AN UNCONTROLLED DOCUMENT downloaded by Lukas Matuska on 16 Feb 2016
Any technical intervention requires certified Hartridge training. Contact Hartridge Ltd for details.
4 line system in HB378 & HF900. A double solenoid valve controls the airflow to a
double acting cylinder. The clamp load is controlled by spacers and conical springs.
backpressure on the piston to drain oil from the unit and provide a backpressure for
the oil.
set and locked at Hartridge. This controls the maximum pressure in the high pressure
hydraulic circuit. The regulator setting must not be adjusted or the machine
safety will be compromised. If the injector access door is opened the solenoid
valve is de-energised and the high pressure is dumped.
The normal operating temperature is set to 40°C and should not need to be altered.
CRi-PC Operating and Servicing Manual
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