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Features of Danfoss STC32-40-50 (SVA65-100-150D) low temperature steel globe valve

Danfoss' STC series manual globe valve products use Teflon valve plates and O-ring seals to achieve higher safety. Each caliber product DN 15 to DN 150, working pressure up to 25 bar, suitable for all common refrigerants including ammonia.
Danfoss STC series manual globe valve can bring you:
◈ Pass 100% online high-voltage test to ensure long-term trouble-free operation
◈ STC manual shut-off valve has a unique back seal function, which can easily replace the stem packing under pressure without shutting down, effectively reducing the system downtime
◈ Polished stainless steel stem and O-ring can minimize the possibility of leakage
◈ The wear-free sealing surface cooperates with the stem / spool bearing connection to ensure product performance and extend service life
◈ High Kv value and low pressure drop to reduce energy consumption
The main technical parameters:
◈ Refrigerant: Suitable for all common refrigerants including ammonia
◈ Temperature range: -50 ℃ / + 150 ℃ (-58 ℉ / + 302 ℉)
◈ Maximum working pressure: 25 bar g (365 psi g)

Installation method of Danfoss STC32-40-50 (SVA65-100-150D) low temperature steel globe valve

installation
When installing the valve, the valve stem must be vertically up or in a horizontal position (Figure 1). The valve should be opened manually and no tools or other devices should be used (Figure 3). The valve is designed to withstand high internal pressure. Nevertheless, the design of the piping system must avoid liquid traps to prevent the system from damaging the piping due to excessive pressure caused by thermal expansion. The design of the pipeline should consider effective protection against transient "liquid strikes" in the system.
note!
STC is a kind of shut-off valve, which must always be kept fully closed or fully open. It is not allowed to be in a half-open state during use.
S ested flow
In order to obtain the best flow characteristics, the valve should be installed according to the flow direction indicated by the arrow on the valve body (Figure 2). The valve can also accept the flow direction opposite to the indicated direction (Figure 2), but in this case the Kv- / Cv value will be slightly reduced.
welding
The bonnet (Figure 4) should be removed before welding to prevent damage to the O-ring in the stuffing box, between the body and bonnet, and the PTFE gasket on the spool. Only materials compatible with the valve body material and appropriate welding methods can be used to weld the valve body. The inside of the valve should be cleaned to remove the welding slag at the completion of welding before reassembling the valve. It should be cleaned in time to avoid welding slag and foreign objects in the valve body and valve cover threads. In the following cases, there is no need to remove the valve cover: when welding, the temperature between the valve body and the valve cover does not exceed
+ 150 ° C / + 302 ° F.
This temperature depends on the welding process and the cooling of the valve body during the welding process. (For example, a damp cloth can be wrapped on the valve body to cool it.) During the welding process, foreign objects such as dust and welding debris should be prevented from entering the valve body. Please ensure that the PTFE valve core sealing gasket is intact. The valve body must not withstand external pressure (external load) after installation. After installation, the outlet end of the shut-off valve must not be exposed to the air. The outlet side of the valve must always be connected to the system or closed, for example with a welded end plate.
assembly
Before assembly, the welding slag and dust in the pipeline and valve body must be thoroughly removed. Before installing the spool into the valve body, check to ensure that the valve is in the maximum opening position.
Tighten
Use a torque wrench to connect the bonnet to the valve body according to the torque value specified in the table (Figure 5).
Color and logo
STC is sprayed with a gray water-based primer on the surface when it leaves the factory. After welding and assembly, the valve must be sprayed with an appropriate protective coating to prevent corrosion of the outer surface of the valve body.