The features of globe valve
Bolted Bonnet;Outside Screw and Yoke ;Rising stems;Metallic seating surfaces.
Body and Bonnet Connection
The body and bonnet of Class150~Class900 globe valves are usually bolted bonnet design .And the Class1500~Class2500 globe valves are usually of pressurized seal design.
Gasket of Cover Flange
Stainless steel + flexible graphite wounded gasket is used for Class 150 and Class 300 globe valve.Stainless steel + flexible graphite wounded gasket is used for Class ,and ring joint gasket is also optional for Class 600.Ring joint gasket is used for Class 900 globe valve.Pressurized seal design is used for Class 1500~Class 2500 globe valve.
Actuation
Hand wheel ,impact hand wheel and gear box is usually used for globle valve actuation.Chain wheel and electric acduator can be also used for globle valve actuation if being reguested by the customers.
Packing seal
Molded flexible graphite is used for packing material.PTFE or combined packing material can be also used if being requested by the customer.The internal surface of the stuffing box,of which area is contacted with the packing,is of excellent finish(Ra 3.2um).The stem surface ,contacting with the packing,should be rolled and pressed after being precisely machined,so as to reach to the high finish and compactness(Ra 0.8um)and ensure the reliable tightness of the stem area.
Belleville spring loaded packing impacting system
If being requested by the customer,the Belleville spring loaded packing impacting can be adopted for enhancing the durability and reliability of the packing seal.
Back seating design
All our globe valves have the back seating design.In most cases ,the carbon steek globe valve is fitted with a renewable back seat.For stainless steek globe valve,the back seat is machined directly in the bonnet or is machined after welding.When the globe valve is at fully open position,the sealing of the back seat can be very reliable.However,as per the requirement of API,it is not advisable to add or change packing by the mean of back seating when the valve is pressure containing.
Seat
For carbon steek globe valve,the seat is usually forged steel.The sealing surface of the seat is spray welded with hard alloy specified by the customer.Renewable threaded seat is used for NPS<10 globe valve,and welded on seat can be also optional if being requested by the customer.Welded on seat is used for NPS>12 carbon steel globe valves.For stainless steel globe valve,intergral seat is usually adopted,or to weld hard alloy directly intergrally.Threaded or welded on seat is also optional for stainless steel globe valve if being requested by the customer.
Stem design
The stem is of integral forged design.The minimum diameter of the stem shall per the standard requirement | |
