Electronics

Power Amplifiers for Pumps

Electronic module for control of a continuous volume flow adjustment with position transducer in axial piston pumps of the PV series.

Flow current can be given by an externally supplied command signal and internal limitation and ramp potentiometers. In this case, the command signals can be generated for example by a PLC.

Features include:

• Flow current adjustment in closed loop control by feedback of the pivoting angle setting.
• Differential input stages for voltage or current signals.
• Ramp generators.
• Min/max adjustment for maintaining the working range to the command value range.
• Adjustable control gain.
• Diagnosis LED for indicating under voltage or position transducer cable breakage.
• Module housing for support rail as per EN 500222.
• Disconnectable terminals.

Power Amplifiers for Valves

Electronic module for the control of pilot operated proportional directional valves with transducer. The flow direction at the valve spool is set by the sign of the set-value voltage. The spool stroke and its rate of change are set by means of potentiometers. The movement profile of the valve spool is controlled by a closed loop feedback circuit in the module.

Flow Valves

Cartridge Type Needle Valves

Needle valve with steel body as screw-in valve for block insertion, optionally with a 30° taper, V notch or rectangular slot. The form of the metering opening influences the fineness of the volume-flow adjustment, which is of course pressure and viscosity dependent. The needle is made of stainless steel and fits into a ring gap in the valve cartridge.

Throttle Check Valves

The throttle check valves of series F allow the adjustment of the flow rate for a defined flow direction. The medium can flow back in the opposite direction via the built-in check valve with little flow resistance.

A two-stage needle allows for very exact setting of smaller flow rates with the first three rotations of the adjustment knob. After 3 more rotations, the valve is completely open. The valve setting can be locked using a locking screw.

Flow Control Valves

2 way flow control valves for pressure compensated regulation of the flow rate. As a consequence of pressure changes, the set value can vary by +/- 5% within the tolerance range. Changes in viscosity and in temperature have the same effect and are to be observed.

Proportional Throttle Valves

The 2-way proportional throttle valves of the TDA series are used to control large oil flows. These valves are designed with 3 stages. The valve poppet is pilot-operated by a sequence spool with seat construction. A magnetic, infinitely variable, adjustable valve with force feedback controls the position of the sequence spool, thus the position of the poppet cannot be affected by different pressure.

Accumulator Discharge Valves

Accumulator discharge valves are preferably used in hydraulic systems where high volume flow rates are discharged from hydraulic accumulators over a short operating period (in the range of milliseconds).

Typical applications are, for example, injection moulding and die casting machines as well as pressing machines of all types.

Manifolds

Manifolds are used to save space when connecting several directional control valves to a common pressure and return line.

Diverse switching arrangements are possible when used in combination with intermediate plate devices and directional control valves. Plugs without designations must not be removed.

Because of the large drilling diameters the pressure drop through the manifold is very low. P and T ports are located on both front faces. All connection ports are designated.

Gauge Isolator Valves

The gauge isolator valve protects the gauge against damage from pressure surges. As soon as the button is released, the valve automatically bypasses the fluid to the reservoir. This maintains the pressure gauge accuracy and prolongs its life expectancy.

Pressure Switches

Electro-hydraulic pressure switches provide an electric signal when sensed pressure rises above or falls below the selected setting.

The spring loaded piston is hydraulically dampened, the pressure difference cannot be set, but is given by the switch hysteresis.

The required operating pressure is adjusted by a set-screw. Unauthorised adjustments may be prevented by fitting a cylinder lock. The electric element is a micro switch with snap-action contact. Three terminals permit application as “on”, “off” or “changeover” switch. The electrical connection is made with a 3-pole plug-in connector to DIN43650 with ground. The plug-in connector is also available with an indicator light.

Pressure Intensifiers

Pressure intensifiers are used wherever a particular section of a hydraulic system has to be pressurised to a substantially higher pressure than the available primary pressure allows (clamping functions). With an intensification ratio of 1 : 4 (1 : 2) it enables a cost-effective system solution especially in clamping applications, with primary pressures up to 125 bar. A pilot operated check valve can be flanged underneath the pressure intensifier for a quick filling and decompression of the high pressure section.

Pressure Valves

Series EVSA and VSA are direct controlled, dampened poppet valves with adjustable spring loading. Three pressure stages with selectable maximum adjustment pressures of 64, 160 and 315 bar are available. The integrated damping spool prevents pressure fluctuations in the transition region. The pressure is set using an adjusting screw, which is locked with a clamping screw. The setting can be secured by means of a cylinder lock if required.

Direct Operated Pressure Valves

Series VS and VB are direct operated pressure valves with manual adjustment, they are spool type valves, manifold mounting. They have 5 pressure stages at NG6, 3 pressure stages at NG10 and 2 adjustment modes. The VS type pressure relief valve is a direct grated spool valve for sub-plate mounting with internal drain to Port T. The connection function is according to DIN 24340-C6-2, whereas the sequence valve VB is a direct operated spool valve with external drain. The sequence valve also allows the application as a pressure relief valve.

Pilot Operated Pressure Relief Valves

The pressure relief valve Series RS* consists of a manual adjusted pilot stage with directional valve for electrically controlled unloading and a cartridge main part, its features are Pilot operated with manual adjustment, 2 interfaces (sub-plate and slip-in, mounting hole), 4 pressure stages, 2 switching types, 2 adjustment modes (screw with lock nut or DIN lock) and remote control via port X.

Proportional Pressure Relief Valves

The pressure relief valve series RE*T have a proportional solenoid operated pilot stage with integral electronics and a cartridge main stage. They have on-board electronics, min/max option, ramp adjustment, very low pressure adjustment of pmin, 4 pressure stages and 2 interfaces.

Direct Operated Pressure Reducing Valves

The pressure reducing valve VM is a direct controlled spring loaded 3 way pressure reducing valve that is open in the neutral position. The valve closes the connection fro P to A (NG06) or B (BG10) when the pre-set pressure is exceeded.

Proportional Directional Control Valves

Direct Operated Proportional DC Valve Series D1FT

The D1FT directional control valve of the nominal size NG6 (CETOP 3) is a proportional valve providing variable flow rates.

This valve is used with integrated control electronics. Typical applications are; soft switching via adjustable ramps for the reduction of hydraulic and mechanical shocks, electrically adjustable flow rates/speeds for automating machine functions.

Pilot Operated Proportional DC Valve

The D*1FW or D*1FT pilot-operated DC valves are available in NG 10 (CETOP5), NG16 (CETOP7 and NG25 (CETOP8).

These valves (*1FW) are controlled electrically with external power amplifiers or used as valves with integrated electronics (D*1FT).

Typical applications include reproducible control actuator speed in rapid/slow speed profiling and smooth acceleration and deceleration performance.