Strainers Globe taps 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 ∆ p In order to ensure that the control device (globe valve and linear actuator specifications) achieves a long service life, it is essential for the valve to be rated for the correct differential pressure
Notes on project design and maintenance
Disposal
B C
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.
Maintenance Project design
Water quality requirements Installing H5..B and H7..N globe valves, 3-way The globe valves and linear cylinders 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 dispensing (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. 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. The water quality requirements specified in VDI 2035 must be adhered to. 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.
v100 , 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 ∆ p
v100 with globe valves fully open
H4..B/H6..N/H6..S globe valve, 2-wayH5..B/H7..N globe valve, 3-way
Throttling circuitInjection circuit with throttling deviceDiverter circuitMixing circuitInjection circuit with 3-way valve ∆ p
v100 > ∆ p
VR /2 ∆ p
v100 > ∆ p
VR /2 ∆ p
v100 > ∆ p
MV ∆ p
v100 > ∆ ∆ p p
MV ∆ p
v100 > ∆ p
MV1 + ∆ p
MV2 ≈ 0 barTypical values 15 kPa < ∆ p
v100 >3 kPa (unpressurized manifold)
For other mixing circuits 3 kPa <
Circuit type ∆ p
v100 <200 kPaTypical values10 kPa < ∆ p
v100 <150 kPaTypical values 5 kPa < ∆ p
v100 >50 kPaTypical values ∆ p
v100 >3 kPa
v100 >30 kPaTypical values
∆ p MV M ∆ p MV2 M M ∆ p MV1 M M Geographic presentation V LRL ∆ VLRL p ∆ VLRL VLRL VR p VR VLRL ∆ p MV ∪ VL VL VL VL VL M ∆ p MV1 ∆ p VR ∆ p VR ∆ p MV ∆ p MV ≈ ∆ p MV2 Synoptic presentation M M M M RL RL RL RL RL Legend
M Globe valve, 2-way with linear actuator
M Globe valve, 3-way with linear actuator Balancing valveVL — SupplyRL … Return Pump Non-return valve Differential pressure across variable-flow section at rated load (e.g.
industrial heat exchanger) Note: Stainers and isolating valves are not shown ∆ p
VR Differential pressure across specified section at rated load ∆ p
MV ENG-93001-93621-08.04-1M Printed in Switzerland ZSD Subject to technical modifications 34