The design of the body and bonnet is calculated to achieve the most regular distribution of stress in all directions, as well as the minimum turbulence and resistance to flow.

Valve bonnets are equipped with a backseat bushing. The yoke is integrally cast on Pressure Classes 150 and 300 up to 12� and up to 10� on Class 600 and higher ratings.

Standard body-bonnet joints of gate valves are machined as follows:

*Pressure Class 600 also available in Ring Type Joint.
Hi - Tech can supply any style of gasket required by customer.

All gates are fully guided to the seats. As standard our valves are supplied with a solid flexible gate that has a tapered H cross-section. The flexible wedge is cast or machined with a circumferential groove to allow the seating surfaces to move independently and adjust to movement of the body seats. This design is beneficial where line loads or thermal expansion of the system is likely to distort the seat face in the valve. This design of gate is ideally suited for steam or other high temperature services and is especially useful to prevent sticking where valves are closed when hot and opened when cold.

Seat rings are designed to greatly reduce and/or prevent any turbulence and avoid damages due to the corrosion. The seat rings are forged or rolled in one piece, and then seal welded and overlaid, if required. After welding and all required heat treating, the seat ring faces are machined, thoroughly cleaned and inspected before leaving for assembly.

The stem connection to the gate is a T-head design which is integral (without welding) with the stem. The accuracy in the dimensions and finishes assure a long life with a perfect tightness in the packing area, resulting in lower fugitive emissions.

The stem-to-gate connection is designed to prevent the turning or the disengagement of stem from the wedge while the valve is in service.

Through calculations and extreme testing, the strength of the stem-to-gate connection has proven to exceed the strength of the stem at the root of its operating thread.

The depth of the stuffing box allows for a sufficient amount of packing, which makes the stem seal. Our standard packing arrangement and stuffing box design meets <100 ppm fugitive emission requirements.

If specified in the purchase order, lantern rings and/or grease injectors can be furnished.

The stem packing is designed and arranged to ensure a maximum seal along the stem during operation or while at position, thus allowing for a greater reduction in fugitive emissions. Our packings are NON-ASBESTOS types.

Hi - Tech can supply any style of packing required by our customer.

The packing gland design is a two-piece self-aligning type. The packing gland has a spherical head that rides within the spherical joint of the gland flange. The packing gland has a shoulder, which restricts the complete entry into the stuffing box bore. This particular design assures a straight compression of the packing as the gland eyebolts are being equally adjusted, without injuring the stem.

The stem nut arrangement and design allows for the removal of the handwheel without allowing the stem and gate to drop into the closed position if the handwheel is removed while the valve is in the open position.

Ball bearings are provided in the stem nut arrangement of Class 150 valves from NPS 14�, on Class 300 valves from NPS 12:, on Class 600 valves from NPS 6�, and on Classes 900-1500 valves from NPS 2�.

Handwheels are designed for easy operation and a comfortable grip. Our valves are also available with gearing, motor actuators or cylinder actuators for the more demanding services.

For normal service conditions, ASTM A194 Class 2H and ASTM A193 Grade B7 nuts and stud bolts are furnished. If specified for high temperature service conditions, ASTM A194 Class 4 and ASTM A193 Grade B16 nuts and stud bolts are furnished. Standard bolting furnished for our stainless steel valves consists of ASTM A194 Class 8 and ASTM A193 Grade B8 nuts and stud bolts.

Hi - Tech can supply any bolting as required by the customer.

Our standard production covers valves with:

• Flange ends with Raised Face (RF), Flat Face (FF) or Ring Type Joint (RTJ) that conform to B16.5.
• Butt-welding ends (BW) that conform to B16.25.
• All face-to-face/end-to-end dimensions conform to B16.10.
• Other special end connections are supplied according to customer’s requirements.

Accessories such as gear operators, actuators, bypasses, locking devices, chainwheels, extended stems and bonnets for cryogenic service and many others are available to meet the customers requirements.