müller coax group

Flow Control Valves

This series comprises valves with two connections that are operated by an electric motor. They are characterized by the fact that the valve stroke can be adjusted steplessly and held in place by a motor using a setpoint signal (4-20 mA or 0-10 V). This makes this series particularly suitable for precise dosing applications, as the servo motor reliably processes setpoint deviations of 1%.

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In particular, the RMQ 20 and 32 series exhibit a particularly favorable relationship between a high-pressure range and high flow rate while at the same time having a very low power consumption thanks to their pressure-equalized design. This allows pressure stages of 16 to 64 bar to be realized. The volume flow rate can be adjusted steplessly from 0 to 20 m³/h depending on the model. They are usually used with liquid media such as coolants, oils, emulsions, or water up to +80°C, but are generally also suitable for gaseous media. The co-axial design ensures a low noise level of the process medium when in operation.

The RMQ 10 and 15 series comprise position-regulating valves in a cartridge design. These valves are characterized by a particularly favorable ratio between a high pressure range and very precise dosing. Due to the design, the pressure stage is limited to 25 bar. The stepless dosing range can be adjusted from just a few drops to 45 l/min depending on the nominal width – please refer to the data sheets for details.

The cartridge valves are also known as "Patronenventil" in German. The valve cartridge is attached to the valve body with three screws. Once installed in the piping system, the system offers the advantage that the valve cartridge can be replaced within just a few minutes if necessary. The tedious dismantling of the entire valve body from the pipeline using a large wrench is no longer necessary; only the three screws need to be loosened. The RMQ 10 and 15 are suitable for a wide range of gaseous and liquid media up to a temperature of +80°C. A version with a hose seal is available for extremely dirty, abrasive or sticky media. The RMQ 10 to 32 valves are available with housing materials made of aluminum, brass or stainless steel depending on the type.

One other characteristic of all RMQ valves is the very low power consumption during the adjustment procedure. Depending on the pressure stage, it amounts to between 10 to 19 watts. After the desired valve position is reached, the motor switches off and the control pipe remains in this position with millimeter precision until the next change in the setpoint. Due to this, this valve series does not have a defined NC or NO home position – when de-energized, the valve remains in the last position reached. As long as there is no change in setpoint value, the valve does not require any energy at all (sleep mode). Hence, the RMQ valves are considered to be extraordinarily energy-efficient. Due to this alone, valves have been successfully used in the past in situations where there was only a very low power supply available at the location. Without control air or a sufficiently powerful power supply unit, the operation of pneumatically or magnetically actuated valves is practically impossible; in such cases, RMQ valves can offer a viable solution thanks to their low power consumption.

As a result of the marginal power draw, the valve components in contact with the media do not warm up even when in constant operation. This makes it possible to use them even for highly sensitive dosing applications such as in test benches, where even the smallest amount of thermal transfer via the valve housing into the process pipeline is not permissible.

Because all RMQs open and close particularly gently, these valves are also used in all situations where smooth and gentle process workflows without pressure peaks, vibrations and switching shocks are crucial, even at extremely high flow speeds.

By default, all valves are equipped with an LED on the cover. This is purely a visual indication of the motor and/or stroke movement on the valve. The LED lights up for as long as the motor is in motion. It turns off as soon as the motor reaches the stroke position and switches off. A flashing LED, on the other hand, indicates a valve fault (valve stroke not achieved) and the motor remains in this position for safety reasons. Usually, such a fault indication can be deleted via a simple "Reset" (pull out connecting plug for 1 sec), but sometimes it is actually large particles of dirt from the process which have gotten stuck between the valve seat and the control pipe, and which need to be removed. In any case, the LED indicator is an effective means of easily keeping an eye on the valve status.

Optionally, the valves can also be equipped with an additional actual value output. Unlike the LED, this allows the stroke adjustment of the valve to be observed electrically and in real time on the customer's machine control system. Because the RMQ valves move slowly due to their design, the difference in time from the setpoint value to the actual value is of particular interest in certain applications. The stroke movement can be directly observed and evaluated using the actual value output in real time, far away from the valve and directly on the machine control system. The actual value signal is accessed via a separate connector on the valve cover. The stepless signal spans a range from "4 mA for valve closed" to "20 mA for valve open". The actual value version can even be retrofitted where necessary.

All RMQ valves can also be integrated on site into a closed-loop control circuit. Generally, in this case the valves are used together with suitable volume flow rate meters that are chosen by the customer. Where it is technically necessary, this combination can indeed achieve the highest accuracy levels and the best results. In such contexts, close collaboration between co-ax with the customer has proven effective in the past for jointly defining the optimal control circuit parameters.

Overview technical data Flow Control Valves

co-ax type orifice connection max. pressure range Kv value
1 - 10 mm thread 0 - 25 bar 0,048 - 2,7 m³/h
15 mm thread 0 - 25 bar 5,9 m³/h
RMQ 20
20 mm thread 0 - 64 bar 7,3 m³/h
RMQ 32
32 mm thread 0 - 64 bar 20 m³/h