BODY AND BONNET
The body and bonnet is designed to achieve most uniform distribution of stress on all sides and minimum turbulence and resistance to flow. The bonnet on valve is equipped with back seat ring up to 12" for Class 150 & 300 and up to 10" for Class 600 or higher. The yoke is cat integrated with the bonnet.

WEDGE
The valve is normally supplied with a solid flexible wedge of which the cross section is tapered H shape.  All wedged are fully guided.  The flexible wedge is cast or machined with circumferential groves to allow the seating faces to move independently and adjust the movement of body seat. It is used where the line load of thermal expansion of system may distort the seating face of valve, and especially useful to prevent sticking that may happen in case the valve is closed at a hot temperature and opened at a cold temperature. Ideally the wedge is suitable for steam and other high temperature service.
 

STEM
The stem connection to the wedge shall have an integrated tee head (without welding) and is rectified in the packing are to ensure a long life and perfect tightness. Though experiments, we have calculated and checked the connections between stem and wedge not to disengage the stem from wedge while gate valve is working. The strength of stem and wedge connections is stronger that that of stem alone at the root of thread.

PACKING
The packing size is designed to secure maximum tightness along the stem, and the standard packing is a non-asbestos type. We can supply and kinds of packing as required by customer.

YOKE SLEEVE
The yoke sleeve is designed to able to be disassembled without discounting bonnet and stem, and provided with ball bearing of 14" or over for Class 150~300 valve, 6" or over for Class 600, and 2" or over for Class 900~1500.

GLAND
The gland is made of two pieces. Packing gland is in contact with the packing which is connected to gland flange though spherical joint. Particular design permits a correct pressure on the packing without any damage to stem due to friction or corrosion.

STUFFING BOX
The snuffing box give maximum packing stem seal.  Lantern ring and grease injectors shall be furnished only if specified on the purchase order.

HAND WHEELS
Hand wheels are designed for easy operation. With gearing, motor actuator or cylinder actuator, it is also available or more difficult services.

BOLTS AND NUTS
Bolts and nuts are made from four different types of steel materials in conformity with the ASTM specifications:

1. A307 GRADE B: It has a minimum tensile of strength of 55,00 psi ( 3870kg/mm^2). The nuts normally used with the machine bolts are hot pressed steel conforming to ASTM specification A307, which usually applied to hinge bolts and nuts.
2. A193 GRADE B7/B16: It usually retains the strength well at an elevated temperature and offers higher resilience to creep that any other high grade steel used as bolting materials. The steel is regularly used in bonnet bolts.
3. CARBON STEEL: It is used in hand wheel nuts, set screws, or nipples.

END CONNECTORS
In our standard production of valves, the flange ends ( RF.FF ) and the face dimensions conform to ANSI B16.5 and ASME B16.10, respectively, and they have a raised face serrated finish type of other finish type as requested. For butt-welded ends (B.W), of which the end to end dimension conform to ASME B16.10, customer must specify the schedule type required ,pipe class, or core diameter.
Ring joint ends (R.T.J) conform to ASME B16.5 and the end to end dimensions follows ASME B16.10.
The other special end connections may be supplied as required by customer.

GEAR OPERATED VALVES
valves can be supplied with gear operators.

MOTOR OPERATED VALVES
Valves can be supplied with actuators, either electric or pneumatic, according to customers' requirements.

ACCESSORIES
We can supply a valve fitted with accessories such as  bypass, locking device, chain wheel, extension stem, etc.
For more details, please call.

PACKING AND GASKET MATERIAL
Packing material supplied in standard valves is non-asbestos graphite, with braided graphite rings and die-formed rings configured to provide reliable and long-lasting performance. Braided rings are coated with zinc dust to inhibit corrosion. Die formed rings are 98% carbon (minimum) and have 50PPM chloride 550 PPM sulfur content.
For standard valves, gasket materials are as follows:
CLASS 150 : graphite sheet type with 304 stainless steel tangled insert. ( 1.6 mm minimum overall thickness )
CLASS 300 : spiral wound 304 stainless steel and graphite
CLASS 600 : same as class 300 or 900
CLASS 900  and 1500 : ring joint

SEAL AREA DESIGN
PK cast steel valves are designed and manufactured to satisfy strict requirements in order to prevent external leakage and to meet fugitive emission requirements of most customers.
Stuffing box finishes of 63 to 125 RMS, stem finished of 16 to 32 RMS control of staginess and concentricity of stems, and controlled diametrical clearances between stem and gland, stem and backseat, and gland and stuffing box, all combine to guarantee consistent performance of stem seals.
Gasket surfaces between bodies and bonnets are strictly controlled to fines guarantee consistent sealing in gaskets areas.