Bellow Seal Valves - Bellows Seal Globe Valve | Bellow Seal Gate Valve

ZECO Valve manufactures high-quality bellows sealed globe valves. Our company guarantees the quality and the perfect tightness of our valves according to EN standards

A valve with a bellows to seal off the stem enclosure is an ideal choice whenever leakage to the atmosphere is intolerable due to toxicity, chemical corrosion, radioactivity, or other health or ecological reasons. In addition, seal welding the body-bonnet seal makes the valve hermetically sealed. The bellows are welded to the stem and to the bottom of the bonnet.

What is a Bellow Seal Valve?

Bellow seal valve is designed with bellow welded onto the bonnet and stem, so that when the stem travels drive the below expansion or decompression. It inherently eliminates the conventional design of possible stem packing leakage. Bellow sealed valves can achieve truly zero leakage; ideal for stringent leakage-free applications like toxic and flammable services. Bellow seal valve is an ideal choice whenever leakage to the atmosphere is intolerable due to toxicity, chemical corrosion, radioactivity, or other health or ecological reasons. In addition, seal welding the body-bonnet seal makes the valve hermetically sealed. The bellows are welded to the stem and to the bottom of the bonnet.

How does Bellow Seal Valves work?

These valves feature accordion-like bellows—i.e., the bellows cartridge component, welded to the valve stem and bonnet. During the valve stroke, the bellows compress or expand along with the sliding stem’s linear motion with little to no friction.

Types of Bellows

Formed bellows: Conval’s standard design, formed bellows begins as a flat sheet (thin wall foil) rolled into a tube and fusion-welded longitudinally forming a single layer. Thin metal layers are combined to form multi-ply bellows. Mechanical or hydrostatic force forms the bellows with wide-spaced rounded folds. Conval has supplied bellows with as many as 6 plies for higher pressure applications.
Welded bellows: Welded bellows are manufactured by welding washer-like plates of thin metal at both their inner and outer circumferences.

Types of Bellow Seal Valves

Include: ANSI Bellow Seal Valves, DIN Bellow Seal Valves, and other standard Bellow Seal Valves, Bellow Seal Gate Valve, Bellow Seal Globe Valve

Bellow Seal Gate Valve

Gate valve with bellow seal acc. to ANSI is applicable to the cutting and connection of pipelines fluid. Stop valve with bellow seal acc. to ANSI is applicable to the cutting, switch, and adjustment of the medium. The medium that is used in various industries such as petroleum, chemical industry, pharmacy, Chemical fertilizer, electric power industry, etc under nominal pressure of CLASS150-900LBS and working temperature of -29~350℃
A parabolic Plug for the switch and the adjustment of fluid is available.

Product Features of Bellow Seal Gate Valve

This product has a logical structure, reliable seal, excellent performance, and nice design.
The stem of the Bellow seal valve is quenched and tempered, and its surface is treated by nitrogen treatment, thus it has good corrosion resistance and friction resistant.
The seal surface is built-up welding with Co hard alloy, which is attrition-resistant, corrosion-resistant, has good friction resistance, and long life.
The stem may show the position of the lift, thus it is clearer.
Bellow seal valve has double seal capability, thus is more reliable.
The part material, flange, and butt weld end dimension can be selected according to current operating conditions and uses’ requirements, so that meet the requirements of various engineering.
Structural formation: BB-BG-OS﹠Y
Driving manner: Hand-operated, Electric-actuated

Applicable Standard of Bellows Seal Gate Valve

Design: API 600、API 6D
Face to face: ASME B16.10
Flange ends: ASME B16.5
Test﹠inspection:API 598,API 6D

Bellows Seal Globe Valve

A Bellows Seal Globe Valve is a compact structure that is a kind of control valve which uses bellows for sealing the valve stem components. The bellows valve has a bellow inside, and the lower end of the stainless-steel bellows is welded to the stem to prevent the system fluid from eroding the stem.

Features of Bellows Seal Globe Valve

The most prominent advantage of any bellows valve is the Double seal design (bellows + packing). So, even if the bellows fail, the stem packing will prevent any kind of leakage to meet the international sealing standards.
It minimizes any loss of medium fluid and ensures safety and environmental protection. This will ultimately improve the safety of the plant where is bellows valve has been installed.
It can act as an energy saver as it contributes to minimizing energy losses due to leakage.
Since the leakage is minimized, it prevents frequent maintenance of the valve. So, it leads to longer valve life.
Owing to longer service life, operating and maintenance cost is considerably reduced.
The rugged bellows seal design ensures zero leakage from the valve stem, thereby providing maintenance-free conditions.
The safety of working personnel is improved with the installation of a bellows valve as emissions of inflammable, toxic, and hazardous chemicals can be minimized.

Features of Bellow Seal Valves

Each valve is tested per API 598.
Every bellow assembly is helium leak-tested to assure zero leakage.
Non-rotating stems prevent torsion below.
Secondary stem seals include:
- Stem backseat
- API 624 stem packing
Lubricant fittings to ensure proper lubrication of stem bushing for efficient opening and closing.
Multiple bellows materials are available: 316Ti, Hastelloy, Inconel, Monel, etc.
All bellows are hydroformed with a minimum of two layers.
Available in pressure classes 150-1500 (All body materials available)

Bellows Seal Valve vs Packed Valves

Packed valves require two seal boundaries: a 360° seal on the stem surface and a 360° seal on the stuffing box wall. The Conval bellows seal valve removes these two leak paths. Conval bellows seal valves are used when packed valves may not reliably contain light gases or hazardous system fluids. In all applications, the 6-ply Inconel welded bellows stem seal is more reliable than sliding stem seals.