Control Valves
Design & Engineering
Our fully computer aided design department will design and specify valves for a wide range of process applications. Supported by a fluid flow test laboratory Northvale development engineers can quickly carry out live testing on valves up to 200mm to verify performance characteristics, Kv ratings and empirical design concepts.
Production Control
The Company operates a real time fully integrated computer controlled manufacturing system, ESCOPE, which maintains total control over all company activities and in particular material supply, stock control and production planning to ensure that we can supply our customers exact requirements quickly and on time.
Product Ranges
- Process Control Valves
- Two Way Valves
- Three Way Valves
- Fluid Control
- Globe Valve
- Temperature Control
- Actuators
- Process Instruments
- Severe Service Valves
- Pneumatic Actuator
- Electric Actuators
- I/P Transducer
- Bellows Seal
- Heating & Ventilation
- Steam Valve
- Water Valve
- Safety Valves
- Pressure Regulating Valves
- Pressure Reducing Valves
- Strainers
- Butterfly Valves
- Flow Regulators
- Manifolds
- Din Valves
- Ansi Valves
- Bellow Steam Seals
- Low Noise Trims
- Valve Repairs
Control Characteristics
N.B. All differential pressures are maximum values for ANSI Class 300 and will need to be derated for other body ratings.
For further information about optimal trim sizes, actuator combinations and spring rates please consult our Technical Sales Department.
Data Sheets
BODY MATERIAL: Cast iron -BS 1452-GR 250 Cast steel -BS 1504-161-GR 480A Stainless steel -BS 1504-316C16
TRIM MATERIAL: Stainless steel, stellite and PTFE.
FLANGES: PN16/25/40. (ANSI125/250, 150/300)
MAX AMBIENT TEMPERATURE: 90° C.
MAX SERVICE TEMPERATURE: According to body material and flange rating.
MAX DIRECT AIR SUPPLY: 6 bar.
SEAT TIGHTNESS: Metal-to-metal seats conform to ANSI B16 104 Class 4 shut off. Soft inserts conform to ANSI B16 104 Class 5 shut off.
ACCESSORIES: Valve Positioner. E/P Converter. 3-way Solenoid Valve. Soft Seat. Hand Jack. Air Filter Regulator. Temperature, Pressure and Level Controllers. End of Travel Limit Switches, Bellows Seal.
ELECTRIC ACTUATORS: Details available on request.
Northvale Korting is dedicated to continual product development; and therefore reserves the right to change dimensional data without prior notice.
How it works
Conventional globe style control valves have to strike a balance between maximum flow capability at full lift whilst maintaining stable control of low flow rates at the bottom end of the range. Achieving a high turndown ratio usually results in the control plug having to operate very close to the valve seat, which leads to wire drawing and rapid erosion wear of the trim. To maintain set point control at these small openings requires very small valve stem movements which the actuator may not be able to match. The valve begins to “hunt” and the whole control feed back loop becomes unstable.
Paragon Trim
Northvale’s new control valve with the unique PARAGON high turndown ratio trim significantly improves the control characteristic at the bottom end of the flow range. This increases the valve’s flexibility and reduces the number of trims required for each line size of valve. These improvements are achieved by the dual action PARAGON trim with its specially profiled plug and two stage compound seat.
Closed Valve
Fig 1
Valve shut off is achieved on the lower seat. The upper controlling seat is not in contact with the plug.
Flows
Fig 2
Fluid entering the valve under the plug passes over the bottom seat and expands into the seat cavity before being throttled through the control annulas around the top seat. Pressure drop is taken across each seat which ensures a smooth transition between upstream and downstream conditions. This two stage feature allows the valve plug to lift well away from the bottom (closing) seat whilst remaining in close proximity to the upper controlling seat.
Normal Flow
Fig 3
Beyond 50% valve lift the PARAGON trim begins to act like a conventional profiled plug valve with control being exercised solely by the top seat.
Contact us with any enquiries and we will be happy to help.