Teknovalves | Behind The Scene

The number twelve (XII, اِثْنَا عَشَرَ; doze, dvanaest, twaalf, tolve) is significant and ubiquitous.

It's the number of months in a year, hours on a clock face, and the number of members on a typical court jury. It is mentioned in the New Testament of the Bible, including Jesus' selection of 12 apostles. The Greeks worshipped 12 major gods of Olympus. The significance of number 12 is visible elsewhere as well - from a dozen eggs to the 12 ribs on the average human to the 12 inches that comprise a foot.

We can go on, but we made the point, did we not?

We take you behind the scenes of how we make our cylinder valves, no marks for guessing – divided into twelve processes, each as important as the other (okay, we have a few favourites but let's keep it secret for the sake of this theme).

We invite you to visit us to see the manufacturing in action, all under one roof.

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design

Cylinder valves are designed to the most stringent specifications and qualified by third party type testing.
Design activities use the latest CAD/ CAM softwares which seamlessly integrate with manufacturing. The design department prepares and controls purchase specifications for every raw material used in the cylinder valves.
Design changes are controlled at every stage and requalified as needed.

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Forging

Valve bodies manufactured from different materials, e.g. Brass, Al-Si Bronze, Carbon steel and Stainless steel, are hot forged. Slugs are cut from bar material with the help of a band saw / slitting saw. The weight of the slug is checked to reduce wastage and avoid underfilling.
An energy-efficient induction process heats slugs. The fast heating avoids prolonged exposure of the slugs to elevated temperatures and ensures finer grain structure and improved ductility.
Infrared Pyrometer monitors the temperature of the slugs just before forging.
Valve bodies are trimmed after forging to remove the flash.

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Stress relieving

Brass forgings are stress relieved to improve the grain structure and relieve any stresses induced during the forging operation.
Carbon steel valve bodies are normalized to reduce internal stresses and improve microstructural homogeneity.
Stainless steel valve bodies are solution annealed to dissolve any precipitates present in the material and transform the material at the solution annealing temperature into a single-phase structure.

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Surface finish

Valve body forgings are shot / sand/corundum blasted to clean the surface and remove sharp edges and oxide layers formed. The abrasive action of the blasting media also strengthens (peens) and polishes the metal, and prepares it for machining.
Stainless steel forgings are electropolished to remove free iron and contamination from the surface. Electropolishing reduces roughness by levelling micro-peaks and valleys and brightens the surface. The preferential free iron enhances chrome/nickel content and makes the surface resistant to atmospheric corrosion and surface degradation.

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Machining

Machining of valve bodies and components is carried out on high precision multi-axis CNC machines.
Multiple operations on the valve body are carried out by turning/milling in a single setup on multi-axis machines to minimize loading and ensure concentricity.
Valve components are machined by loading multiple bars at a time on sliding head machines.

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Marking

Valves are marked by laser etching or metal stamping with the manufacturer's identification, item code, date of manufacture, batch number, inlet and outlet size and standard to which they comply.
Additional markings may include the gas service, working/test pressure, series number, etc. Pressure relief devices are marked for the pressure, temperature and flow rating.

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Chrome plating

Nickel Chrome plating is carried out on brass valves used for medical application to provide pleasing aesthetics and prevent the oxidation of brass. To avoid particle contamination in service, gas wetted areas are plugged before plating.

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Deburring

Valve bodies and components are deburred by hand or vibratory deburring machines. Deburring removes sharp corners and unwanted pieces of material that may remain attached to the workpiece after machining.

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Degreasing

Valve bodies and components are degreased in a close circuit using vacuum solvent technology to remove grease, oil, cutting fluid and particulate matter. The degreasing cycle involves prewash, immersion washing, ultrasonic cleaning, vapour degreasing and drying.

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Assembly

Specialized machines are used to install O-rings / backup rings.
Lubrication is delivered by precise needle valves ensuring accurate dispensation.
Assembly of taper threads with PTFE thread sealant is carried out by an automated tape dispensing machine.
Assembly and testing torques are imparted using electric nut runners.

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Pressure Testing

Each valve is pressure tested for internal leak tightness (through the valve body seat) and external leak tightness (through the gland mechanism) at maximum service pressure.
Pressure testing is carried out by bubble test or pressure differential method.

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Packaging

Valves are packed in customized foam trays manufactured on-site to provide adequate cushioning and protection during transport.
Valves for Oxygen and other highly oxidizing gases are heat sealed to maintain the integrity of the cleaning process. Threads are protected using protective caps.
Foam is free from CFC's or HCFC's and reusable as carton fillers, easy to dispose of, biostable and non- degradable.

How a valve is made

The number twelve (XII, اِثْنَا عَشَرَ; doze, dvanaest, twaalf, tolve) is significant and ubiquitous.

design

Forging

Stress relieving

Surface finish

Machining

Marking

Chrome plating

Deburring

Degreasing

Assembly

Pressure Testing

Packaging

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