The purpose of extension long stem for valve mainly for three reason: Low temp. medium , High temp. medium, Remote operation. 1. Low temp. medium, to reduce heat transportation, keep neck packing warm enough. so long stem was adopted. 2. High temp. medium, to have better heat radiation,to keep neck packing cool enough and also easy for operator touch, extension was considered. 3. Remote control, to enable operator control valve far from pipe valve, extension can also be used.
For center disc butterfly valve, extension long stem only working for limited working temp. scope. They only have one reason: remote control. So the operetor can control valve at safety and convient position.
SGV First stage order for Europe client/ Germany:
8″ 10″ 12″ 16″ 52pcs 150lb Lug type RF/FF Concentric Butterfly Valve with Ductile iron Body: ASTM A395 60-40-18 Disc:ASTM A351 CF8M CF3M Seat：EPDM
No-pin stem design,the disc and stem fixed by spline shaft(to avoid accident risk point), EPOXY Bake paint.
Among them, 44pcs valve with extension from 2.8 meter and 3.8meter, 7.6 meter.
For 12″ with 3.8meter extension, open/close degree under pressure was controled within 4 degree(94degree).
Part of them, to deliver urgent, all valve finished within 2 weeks and deliver them by air in advance.