Original inventor of M ü ller Co ax AG coaxial valve

Full solution to coaxial valve technology: pressure balance design leads to new heights in fluid control

Since the invention of coaxial valves in 1960, M ü ller Co ax AG has been committed to providing reliable valve solutions for controlling gaseous, liquid, highly viscous, particulate, and corrosive media. From simple on-off valves to application specific special valves, and then to complete modular systems, coaxial valves demonstrate excellent performance in harsh operating conditions such as vacuum, high pressure, and high-frequency switching due to their unique pressure balancing structure. The company is headquartered in Fuchtenberg, Germany and has subsidiaries such as m-tech and cx tec. It also has distribution offices in over 25 countries and regions worldwide. Its products are certified according to DIN EN ISO 9001:2008 and 97/23/EG PED, and meet special industry standards such as DVGW, ATEX, and T Ü V.

Core technological advantages of coaxial valves

The essence of coaxial valve design lies in pressure balance - the force on the valve core is independent of system pressure and pressure difference. Whether controlling vacuum or high pressure, its operating characteristics always remain precise and reliable. Unlike traditional valves, coaxial valves do not require a minimum pressure difference to function properly, achieving zero pressure start-up.

1.1 Pressure balance design/normal operation from 0 bar

In the closed state of traditional lift valves, the inlet pressure will act on the valve core to generate a large closing force, which needs to be overcome when opening. The coaxial valve, through a special flow channel structure, allows the medium pressure to act on both ends of the valve core in opposite directions, thereby canceling each other out. Therefore, no matter how high the system pressure is, the required opening and closing force is almost constant. This feature allows coaxial valves to operate in a wide pressure range from full vacuum to several hundred bars without the need for a minimum working pressure difference.

1.2 Backpressure sealing performance

When the valve is closed, the pressure on the outlet side can be higher than that on the inlet side without leakage. This is crucial for piping systems that require prevention of backflow or back pressure.

1.3 Maintenance free/dirt resistant

A coaxial valve has only one moving component (valve core), no valve stem seal, and no external actuator. This minimalist design minimizes wear points to the greatest extent possible. Even if the medium contains a large number of solid particles or fibers, the valve seat will not fail due to particle jamming. Under extreme working conditions, the lifespan of coaxial valves can be more than 10 times that of traditional valves.

1.4 Quick Response

The pressure balance structure allows the electromagnet to overcome only spring force and minimal frictional resistance, so the opening and closing action of the valve can be completed within 30 milliseconds (depending on specifications). This makes coaxial valves an ideal choice for applications that require high-speed circulation control.

1.5 Bi directional flow

Valves allow media to flow in any direction without the need to install multiple valves to achieve bidirectional shut-off. This feature simplifies pipeline design and reduces pressure loss.

1.6 Compact size

Due to the elimination of large pneumatic or electric actuators (coaxial valves typically use direct acting electromagnets or small pilot valves), the overall length and height of coaxial valves are much smaller than traditional valves.

Overview of Product Series

M ü ller Co ax offers 2/2-way and 3/2-way valves, with drive modes divided into direct actuated and externally controlled. The diameter range is DN 1.5-250, the pressure range is PN 0-500 bar, and the connection methods include threads, flanges, SAE, etc.

2.1 Direct acting 2/2-way valve (MK/FK series)

Direct acting valves drive the valve core directly through DC electromagnets, without the need for a pilot air source. Suitable for small caliber (DN 8-50) and medium low pressure (PN 16-100 bar) applications. The Kv value of the typical model MK 10 (DN 10) is 2.6 m ³/h, with a switching time of approximately 25 ms. The valve body material can be selected from brass, galvanized steel, stainless steel without non-ferrous metals, etc; Sealing materials include NBR, PTFE, FPM, CR, EPDM. The temperature range of the medium is -20 ° C to+160 ° C, and the ambient temperature is -20 ° C to+80 ° C.

2.2 External Control 2/2-way Valve (VMK/VFK, VSV Series)

For large diameters (DN 10-250) or situations that require remote pneumatic/hydraulic control, external control valves are used. The pilot valve interface complies with NAMUR/ISO 1 standards and can use 5/2-way or 4/2-way pilot valves. The Kv value of VMK 15 (DN 15) can reach 5.7 m ³/h, with an adjustable switching time of 50-3000 ms. The VSV series covers DN 40-250, with a maximum Kv value of 650 m ³/h (DN 250), suitable for high flow process pipelines.

2.3 3/2-way valve (MK/FK DR series)

The 3/2-way valve has three interfaces (A, B, C) for diverting or selecting the flow direction. It has a switching overlap function inside, which prevents all ports from being closed or opened simultaneously at the moment of switching. DR NC type is normally closed (A → B), DR NO is normally open (A → B). The technical parameters are similar to those of the same specification 2/2-way valve, but with a slight increase in length.