Delta Controls Gate Valves (former NDSM - RSV - M & J Gate Valves)

Provides high quality valves for standard or specialized applications

Delta Controls designs to your specific requirements whether your needs dictate high pressure ratings, use in low temperature environments or protection for use with corrosive materials. Our engineering skills are based on many years of practical experience, in close liaison with our clients, contractors as well as with manufacturers. We are therefore ideally suited to appreciate the constraints and problems encountered by design and operation engineers. Approval on our products has been obtained from the world's leading oil & gas companies.

The design of Gate Valves allows the widest range of applications

Temperature range
The operating range of NDSM gate valves is so wide, that they are as unaffected by tropical heat as by artic cold.

Size range
NDSM gate valves are supplied in a comprehensive range of sizes from 4" to 60".

Pressure range
NDSM gate valves are available conforming to the ANSI classes 150 to 2500 lbs., offering safe working in line pressures up to 9000 psi ( 620 bars).

Material range
NDSM gate valves are constructed from a range of materials for use under different service applications, thereby combining reliability with economy.

Suitability range
NDSM gate valves are suitable for use with a wide range of gases, liquids and vapours, including moderate corrosives.

Fire resistance
NDSM gate valves offer the highest protection, as required by specifications nowadays.

Applicable standards
All NDSM gate valves are supplied fully lubricated for life, thereby eliminating any need for lubrication during service.

Compatibility
Because all NDSM gate valves are of welded plate construction, unlike ball valves they may easily be manufactured to suit the customer's individual technical requirements.

Operating temperatures
All standard NDSM gate valves operate within the temperature range of: -50°F to 250°F (-45°C to 120°C) exhibiting a significant improvement over the API 6D specified range of: -20°F to 200°F (-30°C o 93°C).
Additionally, for use in more extreme conditions, NDSM gate valves can be supplied for operation down to: -76°F (-60°C).

Internal Construction

The gate
The gate operates between two spring seal rings, ensuring both up and downstream sealing, yet totally eliminating jamming. To improve corrosion resistance, the gate and sealrings are electroless nickel plated.

Seal and seal ring assembly
Each one-piece nylon gate seal is retaining in a metal seal ring, being housed in a seat ring. The seal rings are spring loaded and constrained in their travel by the shoulder bolts. The springs maintain continuous pressure of seal rings on the gate, compensating for contraction and expansion due to temperature changes. Additionally, with the valve in the closed position, at a higher pressure, the downstream springs will be compressed, bearing the seal more strongly to the gate, whilst the upstream spring aid the line pressure to maintain a perfect seal. The design of these seals makes them immune to cold flow and permanent set, or sticking and galling, experienced with metal to metal sealing valves. Sealing between the seal ring and the seat ring is achieved by an O-ring.

Seat rings
The static metal seat rings which house the seal rings are retained in necesses in the body, and sealed with O-rings. The seat rings are so designed that no excess body pressure may build up, due to external temperature, as internal body bleeding compensates for the pressure differential.

The body
The robust, all steel bodies of NDSM gate valves are constructed from welded plate designed to absorb all pipeline stresses without deformation, and much higher pressures can be tolerated as a result of design safety factors. Another beneficial feature of this design, over standard ball valves, is that full servicing may be undertaken without the removal of the valve from the pipeline (field repairability).

Stem sealing
The stem seal consists of a lantern ring and spring loaded chevron rings which automatically compensate for wear. This design eliminates the requirement for regular stem seal maintenance, allied to over-compression of the seal, a detrimental feature of the gland packed seal design. Although under normal service conditions no maintenance is required, the complete stem seal assembly can be removed and replaced with the valve in position and operating normally.

Block and bleed facility
NDSM gate valves are equipped with vents for the facility to block and bleed both the lower and upper parts of the body with the valve operating in the locked open or closed positions.*
* The short body valve can only be blocked and bled in the locked closed position.

Operation
NDSM gate valves can be supplied for hand, electrical, hydraulic and pneumatic operation, to suit a client's requirements and system compatibility.

Options
1. Reduce bore gate valves with the same face to face and end to end dimensions as full bore valves in the same pipe size and classification.
2. Short body gate valves with IF by IF connections, with shortened base plates for lowering into line without interference.

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