Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12Australian Pipeline Valve - Installation, Operation and Maintenance Manual 5 SOFT SEATED PLUG TYPE NEEDLE VALVE - S-H1, S-M5A, S-M5F, S-M9S maintained and the interpass temperature should not exceed 93°C (200°F). GTAW weld type should be employed with argon gas and a maximum diameter weld rod of 1/8”. Only a certified welder with experience in welding this type of valve should be used. 2 . 0 O P E R A T I O N The user should ensure suitably qualified specialist engineers have matched the valve type to the valve service application and ensure valves are properly installed. Valves have moving and wearing parts and depend on long-term preservation of highly finished surfaces on these parts for satisfactory valve performance. 1. The use of excessive force, additional leverage or over cheating to operate the valve handle is not recommended. This practise can cause valve damage. 2. All needle valves have rising stems with right hand thread. Rotate the handle counter-clockwise to open and clockwise to close. 3 . 0 M A I N T E N A N C E Valves which remain in one position for long periods of time are even more likely to require maintenance attention due to the loss of effective lubricants in threads, aging of packing, surface corrosion or moving parts or accumulation of harmful solids. Depending on the surface conditions, environment type, temperature, frequency of use, pressure, etc. In some applications it may become necessary to schedule periodic partial or full cycle exercising and maintenance of these valves. 1. Stem packing leakage usually results from seal wear, and can usually be corrected by tightening the bonnet bushing. Over tightening can cause high stem friction, accelerated wear and shortened stem seal life. 2. If stem packing replacement is needed, safe practice requires depressurising the valve before removal of the bonnet bushing. Use of backseat (where present) to permit repacking under pressure should be considered unsafe. Always wear appropriate safety wear and ensure all fluids and media are drained prior to commencing maintenance.