Global Valves - BELIMO - #34

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ENG-93001-93621-08.04-1M • Printed in Switzerland • ZSD • Subject to technical modifications BC 34 Notes on project design and maintenance Maintenance • The globe valves and linear actuators are maintenance-free. • Before any kind of service work is carried out on control devices of this type, it is essential to isolate the linear actuator from the power supply (by unplugging the power lead). Any pumps in the particular part of the piping system concerned must also be switched off and the appropriate isolating fittings closed (also allow everything to cool down first if necessary and reduce the pressure in the system to atmospheric). • The system must not be returned to service until the globe valve and the linear actuator have been properly reinstalled and connected, and the pipework has been refilled in the proper manner. Disposal When a control device (globe valve and linear actuator) has come to the end of its service life, the two parts must be dismantled and segregated into different materials before being disposed of. Project design Installing H4..B, H6..N and H6..S globe valves, 2-way The valves are throttling devices and must therefore be installed in the return line of the system in order to ensure minimum thermal stress on the seals in the fitting. The specified direction of flow must be adhered to. Installing H5..B and H7..N globe valves, 3-way The valves are mixing devices. The prescribed directions of flow for specific applications must be adhered to. Whether they are installed in the supply or the return of a system depends on the type of hydraulic circuit that is employed. In the case of a diverter circuit, a balancing valve can be installed in the bypass line. Water quality requirements The water quality requirements specified in VDI 2035 must be adhered to. Strainers Globe valves are relatively sensitive control devices. In order to ensure a long service life, it is advisable to fit strainers. Sufficient isolating valves It is essential to ensure that sufficient isolating valves are provided. Correct valve selection and sizing In order to ensure that the control device (globe valve and linear actuator) achieves a long service life, it is essential for the valve to be rated for the correct differential pressure Äpv100, i.e. with adequate valve authority (Pv > 0.5). The differential pressure pHv depends on the type of hydraulic circuit in which the valve is used. Differential pressures Äpv100 with globe valves fully open H4..B/H6..N/H6..S globe valve, 2-way H5..B/H7..N globe valve, 3-way Throttling circuit Injection circuit with throttling device Diverter circuit Mixing circuit Injection circuit with 3-way valve Äpv100 >ÄpVR/2 Äpv100 >ÄpVR/2 Äpv100 >ÄpMV Äpv100 >ÄpMV Äpv100 >ÄpMV1 + ÄpMV2 0 bar Typical values 15 kPa <Äpv100 <200 kPa Typical values 10 kPa <Äpv100 <150 kPa Typical values 5 kPa <Äpv100 >50 kPa Typical values Äpv100 >3 kPa (unpressurized manifold) For other mixing circuits 3 kPa <Äpv100 >30 kPa Typical values Äpv100 >3 kPa RL VL RL VL Äp Äp VR VR M M RL VL ÄpMV2 ÄpMV1 M VL RL ÄpVR VL RL ÄpVR M M VL RL ÄpMV �¾ 0 VL RL ÄpMV2 ÄpMV1 M M RL VL ÄpMV 0 M ÄpMV VL RL M RL VL ÄpMV M Geographic Circuit type presentation Synoptic presentation Legend M Globe valve, 2-way with linear actuator M Globe valve, 3-way with linear actuator Pump Non-return valve Balancing valve VL — Supply RL … Return ÄpVR Differential pressure across specified section at rated load ÄpMV Differential pressure across variableflow section at rated load (e.g. heat exchanger) Note: Stainers and isolating valves are not shown