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Related Manuals for WEBTEC DHT 2 Series
Summary of Contents for WEBTEC DHT 2 Series
- Page 1 Webtec Products Limited Digital Hydraulic Testers DHT Series 2 DHCR Series 2 www.webtec.co.uk...
- Page 3 Introduction DH Series Digital Portable Hydraulic Testers have been designed for easy connection to a hydraulic circuit so that flow, pressure and temperature can be readily checked. To facilitate easy operation all common engineering units can be selected and the display update time can be varied.
- Page 4 5.0; 5.2 Do not use with Water The standard Webtec Hydraulic Testers are designed for use with mineral oil having reasonable lubrication properties. They are not suitable for use with water or fluids with a high water content. If a tester is used with water it should be flushed immediately after use with white or methylated spirit or similar and then flushed with mineral oil to minimise any internal corrosion.
- Page 5 Operation Models: DHT and DHCR Temperature The thermistor type temperature transducer is in contact with the oil flow and temperature is displayed on the left hand side of the digital display. Temperature from the internal transducer is displayed in the INT and TACH position; temperature from a remote turbine is displayed in the EXT position.
- Page 6 ON Button The unit is designed to turn off automatically after approximately 15 minutes to conserve power. When this occurs user programmed values are retained in the memory. The unit is restarted by pressing the “ON” button. Bi-Directional Loading Valve The reverse flow valve gives positive shut-off and pressure control in both directions of flow.
- Page 7 Programming Models DHT and DHCR The DHT and specified DHCR Testers are pre-programmed with the calibration number (PPL) as follows: INTERNAL meter factor to suit the tester turbine, EXTERNAL meter has a standard calibration number and the actual calibration number from the turbine must be loaded into the unit.
- Page 8 Instructions for using the portable Hydraulic Tester Models - DHT and DHCR 0.0 The Tester is designed to measure flow, pressure, temperature and rpm. It can take full system pressure up to 420 bar (depending on model) and measure flow in both directions for motor and cylinder testing.
- Page 9 2.0 Standard Test Conditions Position the Hydraulic Test Unit as described in paragraph 3.0 or 4.0. Open loading valve. (Rotate counter-clockwise) and select high flow range. Start pump momentarily to ensure that oil flows freely through the hydraulic system, then run pump at normal maximum speed. Do not change pump speed while using the loading valve.
- Page 10 Pump flow at rated pressure can now be checked against the pump manufacturer’s specifications. The decrease in flow from the minimum pressure to maximum pressure determines the pump condition. Typically a worn or damaged pump will lose 20 - 30 percent. A pump that delivers low flow at both minimum and maximum pressure indicates suction problems.
- Page 11 It is not unusual for a relief valve to start cracking open below the maximum pressure setting causing considerable leakage and loss of machine performance. The cracking pressure can be checked by increasing the pressure slowly and noting the pressure at which the flow starts falling rapidly to zero.
- Page 12 5.0 Directional Control Valve ‘In-Line’ Test (See drawing B.1) using DHT or DHCR 5.01 To check the relief valve pressure setting where relief valves are integral with control valve, install flow meter in the cylinder line as shown in drawing B1,ensuring that loading valve is open (turn anti-clockwise).
- Page 13 Alternative Cylinder and Motor Test 5.31 Both motors and cylinders may also be tested as shown in drawing B.2. Disconnect the two lines from the motor and connect the tester into these lines. Fully open the loading valve, start the pump and bias the directional valve to allow flow to the inlet port of the tester.
- Page 14 Photo Tachometer 6.0 General Description The photo tachometer consists of the coaxial photo tach head, reflective tape and built-in connecting cable. RPM is displayed in the right hand side of the digital display when TACH is selected on the rotary switch. Pressing the units button switches to RPM or RPM/N. RPM assumes the sensor provides one pulse per revolution of the shaft.
- Page 15 Ensure the plug on the flow block is correctly connected. WARNING: Care should be taken while removing the turbine assembly. Damage to the bearing will cause a loss of accuracy and the tester could malfunction. For recalibration contact Webtec Products Ltd or your local sales office.
- Page 16 Loading Valve DHCR Testers up to 125 lpm 30 gpm with HV100 Loading Valve If the handle becomes difficult to turn under pressure or will not close, remove the handle assembly with a 7/8“ AF spanner. Check for worn valve spindle and seat, damaged seals or contamination.
- Page 17 Loading Valve DHT & DHCR Testers 300 & 400 lpm Models If the loading valve becomes difficult to turn under pressure or will not close, remove the 4 socket screws. Check for worn valve seat, damaged or leaking seals and contamination. Note: If the pressure does not increase progressively when the loading valve is operated, check if the safety discs have been ruptured.
- Page 18 Loading Valve DHT & DHCR Testers 500 lpm & above If the loading valve becomes difficult to turn under pressure or will not close, remove the 4 bolts. Check for worn valve seat, damaged or leaking seals and contamination. Note: If the pressure does not increase progressively when the loading valve is operated, check if the safety discs have been ruptured.
- Page 20 Tel: +33 (0) 3 27 82 94 56 Fax: 02 31 97 59 710 Fax: +33 (0) 3 27 82 94 55 e-mail: sales@webtec.co.uk e-mail: ventes@webtec.fr http//:www.webtec.co.uk http//:www.webtec.fr Webtec Products Limited reserve the right to make improvements and changes to the specification without notice.