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DEMAC rangeRotary unions, slip ring assemblies and sensors
Go to GR, 9900, HD and HDAtex rotary unions or LR sensors. To replace a part integrated into a reel, also record the part number of the complete assembly.
Choose a rotary union or sensor
Rotary unions
GR-2
Family of rotary unions with two hydraulic lines.
View part numbersGR-4
Rotary union with four hydraulic lines.
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9900 series
BSP, JIC or mixed connections depending on part number.
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HD series
Multi-line rotary unions; select according to the drawing and circuits.
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HDAtex
Identification of the configuration and ATEX documents to be confirmed.
View part numbersTravel and inclination sensors
Identify the part and its installation position
Specify whether the enquiry concerns a part integrated into a reel or a component mounted separately on the machine.
Part integrated into a reel. First provide the part number of the complete assembly and a photograph of the fixed connection.
Mounting on a boom or articulated arm. Record the angle to cover, lines and available dimensions.
Mounting on a rotating tool. State the tool type, required rotation, circuits and connections.
External resemblance is not enough to confirm a replacement part number.
Compare rotation, lines and connections
Check the permitted angle, number of lines, pressure, connections and overall dimensions together. Limited rotation cannot replace continuous rotation.
This GR and 9900 selection comes from the general catalogue. The specialised rotary union catalogue presents other configurations, including multi-line HD units; these rows do not summarise the entire offering.
| Family | Lines | Rotation | Pressure | Fittings |
|---|---|---|---|---|
 GR 2 | 2 | 360° | 240 bar | 3/8″ and 1/2″ |
| GR 1 and GR 5 | 2 | 270° | 240 bar | 1/4″ to 3/4″ |
 GR 4 | 4 | 180° | 240 bar | 3/8″ and 1/2″ |
 9900 series | 2 | 180° | to be confirmed | BSP, JIC 37° or mixed |
The 180° limit applies to the GR-4 shown in this table, not every DEMAC four-line rotary union. For a different rotation, send the full requirement to identify a compatible design.
Compare the drawings for the part number: a GR-4 is listed between 230 and 264 mm, compared with 63,5 to 136 mm for a GR-2. These ranges do not provide a size ratio applicable to all variants.
9900 series: selection is based on threads
On the 9900 series, identify the inlet and outlet fittings precisely, then check the part-number specifications. Thread type alone does not determine permissible pressure.
Record fitting type, size and sealing surface: BSP and JIC 37° denote different connections.
Check both sides of the rotary union. Do not select an adaptor from apparent diameter alone: connection compatibility and the overall dimensions of the assembly must be checked.
A potential source of confusion: JIC 37° and JIC 74° denote the same fitting. 37 is the half-angle of the cone; 74 is the full angle.
Measuring rather than transmitting: sensors
To replace a sensor, record travel, output signal, any inclination measurement, connectors and mounting. Then compare the families in the table.
| Family | Travel | Linearity | Angle | Output |
|---|---|---|---|---|
 LR120 | 2 or 4 m | 0,15 % | no | 0 to 100 % |
 LR195 | 5 or 11 m | 0,15 % | optional inclinometer | 0 to 100 % |
 LR series | 10 to 50 m | 0,25 % | 0,4° or 0,01° | Volts, mA or CANbus |
Linearity and accuracy are not interchangeable. Check the specifications for the part number against the usable travel and required signal, without turning a single table value into an overall accuracy for the installation.
Output and interface. A CANbus variant does not directly replace an analogue variant: check the protocol, measurement specifications and compatibility with the PLC.
If the sensor is associated with a load limiter, include its part number and the input specifications expected by the system. See also the cranes and telescopic booms application.
ATEX
For an ATEX requirement, send the existing marking, location classification and required documents. Applicable variants and evidence must be checked by part number; see the ATEX.
What to send for a quotation
- For a replacement: full part number, photograph of the nameplate and views of the existing installation.
- Actual angle of rotation, including maximum travel, or continuous rotation.
- Number of lines, diameter and thread type on each side.
- Pressure, flow rate and fluid.
- For a sensor: travel to measure and required accuracy, with its unit and measurement conditions.
- Whether angle measurement is required and the accuracy required.
- Output expected by the PLC: volts, milliamps or CANbus.
- Available space and achievable mounting hole centres.
Quotations and technical advice on request.