Through Conduit Isolation Valves

Remosa Through conduit isolation valves are specifically designed to carry out the tight shut-off of plant lines, and are capable to handle several process media, as dust-loaded gas or multiphase coke fluids. They are typically installed between Reactor Overhead and Fractionator tower. They can be also efficiently used in the Delayed-Cocking plant, as coke discharge valves or drum top isolation valves.

Following the same philosophy of all the Remosa products, their design is fully customable, and therefore they can be installed in both vertical and horizontal position.

It is possible to identify six main parts in Remosa's Through conduit valves.

  1. Valve body, composed of a main body, an upper bonnet and a lower bonnet.

  2. Valve Gate, consisting of two main retaining plates connected by a support. The upper side of valve gate is designed to host a double disc system, which is able to provide the tight shut-off, thanks to its wedge design. The lower side hosts a full-bore opening, allowing the gas flow during the normal operating conditions.

  3. Support plates, behaving as a cage for valve gate, allow at the same time the proper movement of valve gate, and a sealing effect against the dust income inside the valve.

  4. Stem – connected to the gate through a set of Belleville springs, it is able to drive the gate in both opening and closing directions, and, once closed, to energize the two discs against the seats, guaranteeing the tight shut off.

  5. Motor - it can be hydraulic and pneumatic or electric. Its action is the beginning of a kinematic chain; it is usually provided with emergency mechanical drive section.

  6. Kinematic chain - through the connection between the motor and a threaded bar. Threaded bar operates always outside the valve. Such design require additional external room for the extension of the threaded bar, but it guarantees a better and easier maintenance especially for large size valves.

Both hot wall design and cold wall design are available for through conduit valve bodies, depending on customer's requirements. For cold wall design the main body is made of carbon steel plates with the internal parts made of stainless steel; for hot wall design the whole valve is made of stainless steel.

The valve body is manufactured through welded plates, cut and bent at Remosa's workshop. The shape of the valve body is designed to attain the right wall thickness and the lowest possible valve weight. Finite Element Analysis (FEA) is always carried out to assure an optimal and reliable design.

Upper and lower bonnets are made of large steel plates, and their thicknesses are carefully calculated to optimize the valve weight. The strength and rigidity of upper and lower bonnets are increased through stiffening ribs, hence assuring high rigidity to the whole valve body.

The operation of Remosa Through conduit isolation valves can be summarized as follows:

  1. In open position, thanks to the full-bore gate side, the through conduit valve behaves as a dust-proof conduit and it operates as a pipe without any geometrical discontinuities.

  2. Valve gate is driven between two adjustable support plates. Their position can be adjusted through a set of registers, ensuring the dust-tight function also during the normal operating conditions.

  3. Valve body sealing in open condition is ensured by an expansion bellow installed inside the open side of valve gate, and by a gasket providing the desired sealing. A further system to avoid the income of dust inside the valve body is carried out through a continuous purging of the valve body itself, also assuring the tight shut-off when the valve is in closed position.

  4. When the electric (or hydraulic, or pneumatic) motor is operated, valve gate is driven by the stem, and the support plates behave as a cage to steer the gate in the desired position.

  5. The gate starts its closing action. The Belleville springs on the top of valve gate prevent the early expansions of the valve discs and their sticking inside the support plates.

  6. Once the gate has reached the closed position, the stem compresses the Belleville springs forcing the wedge between the two discs. Such action provides the disc spreading and their efficient contact on the seats and ensures a reliable sealing of the pipe line.

Through conduit valves are shipped on a skid manufactured by Remosa to prevent any valve movement during the transportation, and guarantee a safe shipping to site.

Remosa Through conduit isolation valves can be supplied with any local certifications, like PED, ABSA, GOST-R and others.