Close with an eccentric
To order, you need to determine the nominal flow, working environment, maximum pressure and temperature, tightness class and control method. UKSPAR specialists will help you check the compatibility of the valve with the project.
The models in the catalog have a declared tightness class of "A". The available DN range depends on the series: the required size should be checked directly in the product card or the current technical catalog.
How to choose a flanged gate valve with an eccentric
First of all, the flanged valve with eccentric is selected according to the diameter DN and pressure PN. The connection dimensions must correspond to the mating flanges, and the construction length to the location on the pipeline. The flow direction, temperature and sealing material are also taken into account.
The control method depends on the diameter and the level of automation. The gearbox simplifies manual opening and smoothly moves the disc. The electric drive provides remote control. The pneumatic drive is suitable for fast cycles, but the possibility of its installation and the required torque should be agreed for the specific model.
For an automatic drive, the supply voltage or control air pressure, operating time, degree of protection and the need for limit switches are additionally determined. It is important to provide a method of manual control in the event of a power failure.
Design and operating principle
The main elements of the valve are the body, the rotating disc, the stem, the seat, the seal and the actuator. Turning the stem a quarter turn puts the disc in the closed position: it presses against the seat and blocks the passage.
Eccentric means the axis of rotation is offset from the disc or sealing surface. The contact with the seat is reduced over most of the stroke, and the pressure is applied at the end of the closing stroke. This reduces friction and wear.
Double and triple eccentric
The double eccentric has two axis offsets. The disc moves away from the seat faster, so the seal has less friction and retains its properties longer. This solution is common in large DN water fittings.
The triple eccentric adds angular displacement to the sealing surface. Contact with the seat occurs mainly during full closure, which allows the use of a metal seal in more difficult modes. The type of eccentric for a specific model must be confirmed by the technical data sheet.
Housing and seal materials
In models P101 and P102, the body and disc are made of high-strength cast iron EN-GJS500-7 and the seals are made of EPDM. They are specified for water and air and temperatures up to +70 °C. The seals are always selected according to the composition and temperature of the flow.
EPDM is well suited for aqueous environments, but compatibility with specific additives must be checked separately. The tightness and service life of the seat depend on the correct choice of elastomer.
Steel and stainless steel are used in other industrial valve designs if the environment requires it. The material of a particular valve should be checked in its data sheet.
Advantages of eccentric valves
The offset axis reduces friction between the disc and the seat, so the seal wears less. This maintains tightness, makes handling easier and extends the service interval. The 90° rotation ensures quick flow shut-off.
Among the advantages:
- work on large DNs;
- choice of manual or automated drive;
- integration into the control system.
At the same time, high pressure requires checking PN, allowable drop and torque.
Areas of application of flanged valves
Eccentric flange valves are used in water supply networks, pumping stations, treatment plants, technical water and air systems. They are suitable for large diameters and remote control.
For heat power, aggressive media or special processes, temperature, sealing and documentation must be checked. For selection, please provide UKSPAR specialists with DN, PN, media, temperature, flange type and desired actuator.