Wafer Type Ball Valves: flat body manufacturer in AISI 316, clamped between flanges

KTN Valves manufactures wafer type ball valves in AISI 316. The body has no flanges of its own: a flat disc clamped between the two pipe flanges by the through bolts. It is the shortest and lightest execution of the ball range. PTFE seats give class VI shut-off, lapped metal seats class 600 and class 900.

Category overview

A wafer type ball valve is a quarter-turn valve whose body has no flanges machined on it. KTN is a wafer type ball valve manufacturer in AISI 316, with a soft PTFE seat or a lapped metal seat, inside its wider range of industrial ball valves.

Removing the two flanges changes the two numbers a pipe designer works with. Face to face becomes the shortest of the range and weight the lowest, which turns into rack space and support steel.

Few manufacturers build one. Most catalogues reserve wafer mounting for the butterfly valve, so a plant needing tight shut-off in a short face to face buys a flanged valve heavier than the line requires. KTN builds both, and quotes the wafer style ball valve to drawing.

How to choose a wafer type ball valve

Seven points close the specification.

• Check there is a flange on both sides. For an open end, use the flanged ball valve or the threaded ball valve.
• Flange drilling. DIN EN 1092 or ANSI B16.5, declared at order. The two bolt patterns differ.
• Nominal size. Given in DN. A 25 mm wafer type ball valve is DN25, one inch; convert imperial drawings with the DN to inches conversion table.
• Pressure and temperature. They decide the seat. PTFE covers general service, the metal seat takes over from class 600.
• Body and ball material. AISI 316 as standard, other grades to drawing.
• Abrasion. Solids score a plain ball. KTN applies stellite hardfacing on request.
• Actuation. Lever or pneumatic and electric actuator on the ISO 5211 pad.

Applications and sectors

The wafer execution is the compact shut-off valve of the ball range. KTN supplies it where space and weight are real constraints: skids and packaged units, water treatment and desalination, chemical and petrochemical process, power, steam and thermal oil, pulp and paper, mining and marine.

The pattern repeats: a rack where every centimetre of face to face is multiplied by dozens of valves, or a module where valve weight sizes the frame. In abrasive duty the combination that holds is a metal seat with a stellite ball.

Types and executions we manufacture

KTN manufactures four executions without flanges of their own. Seat and pressure class separate them.

All four carry body and ball in AISI 316, an ISO 5211 top flange and the stellite option. The metal seated versions share their seat with the metal seated ball valves range, which extends to class 2500.

What a wafer type ball valve is and how it works

A wafer type ball valve shuts by turning a drilled ball a quarter turn between two seats. What changes is how the body meets the pipe: no flanges, no threads, no weld ends. It is centred inside the bolt circle of an existing flanged joint, one gasket per face, and the studs hold it.

Flat body construction

Wafer flat body ball valves take their name from the body shape. It is a flat disc, barely thicker than the ball it houses, machined flat and parallel on both faces, with a gasket surface around the bore. There are no flange hubs and no bolt holes through the body: the clamping load arrives from outside, through the studs passing around it.

That geometry produces the two figures the designer buys. The shortest face to face fits more equipment in one pipe run, and the lowest weight cuts supports and the steel under them.

Wafer versus flanged

The wafer body wins on the three quantities measured on site: length, weight and installed cost. The valve is cheaper too, since two flanges are no longer part of it. Against the equivalent DIN flanged ball valve the difference shows in transport and supports.

The penalty appears at dismantling. Removing a wafer valve means pulling the studs and separating both pipe flanges, so the line drains and the spool needs support. A flanged valve comes out through its own two joints. Where removal is frequent, that outweighs the kilos saved.

Wafer ball valve versus wafer butterfly valve

Both share the same mounting, so the comparison is clean. The ball leaves no obturator in the bore when open, while a butterfly valve keeps disc and shaft in the stream, which costs pressure drop. The ball seals better as pressure rises, because its seat is a full ring around the sphere. The butterfly takes the large diameters, where its price per DN falls faster.

Materials, balls and seats

KTN machines body and ball in AISI 316. Enquiries for a ball valve wafer in SS304 are frequent, so the answer is worth stating plainly: the standard stainless steel wafer ball valve from KTN is 316, not 304. Its molybdenum resists chlorides. Other grades, 304 included, are quoted to drawing.

For abrasive service the ball takes a stellite hardfacing on request, which stops the scoring suspended solids produce on a plain ball.

The seat changes the valve more than the body does. PTFE seals by deformation, gives class VI to ANSI/FCI 70-2 and keeps torque low. The lapped metal seat takes the same body to class 600 and class 900 and holds temperature and abrasion, at the cost of torque.

Connections, standards and actuation

The wafer body mounts between DIN EN 1092 or ANSI B16.5 flanges, and the two drillings do not match. Bolt circle, hole count and stud diameter differ, so the pattern is declared at order and cannot be adapted later. The guide to flange faces also checks that both mating flanges share a gasket face.

An ASME B16.5 forged wafer type ball valve enquiry is about the joint, not the valve ends: B16.5 is the drilling of the flanges it is clamped between. KTN builds body and ball in AISI 316 and works to drawing.

Studs and bolt load

With no flanges of its own, the valve depends on the through bolts. That single torque seals two gaskets at once and holds the valve centred. Tighten in a cross pattern and in stages, with studs, nuts and gaskets rated to the class of the line.

Uneven tightening is the usual failure. One face ends up short of load and leaks at the gasket, while the ball seat is intact and gets blamed.

Actuation is resolved on the ISO 5211 top flange, so an actuator bolts on without a bracket made to measure. Size it on breakaway torque with margin, never on nominal. That figure rises with the class and with the metal seat.

Buying wafer type ball valves direct from the manufacturer

KTN quotes the wafer execution from seven data points.

• Nominal size in DN or inches
• Flange standard it mounts between: DIN EN 1092 or ANSI B16.5
• Class or PN of the line
• Body and ball material, and whether the ball is stellite coated
• Seat: soft PTFE or lapped metal to metal
• Fluid, pressure and temperature in service
• Actuation: lever or actuator on ISO 5211

Buying from the factory rather than from a stocking supplier removes the margin and opens the made-to-drawing route. Every order ships with a certificate of origin, EN 10204 3.1 on request. To replace another brand, send the previous manufacturer reference and drawing: KTN builds equivalents from them.

Send the specification through the contact page or call +34 937 818 219.

Why choose KTN as your manufacturer

Kara Technology News, S.L., trading as KTN Valves, machines and assembles this range at its own plant in Rubí, Barcelona (Ctra. Rubí-Sabadell km 13, nave 7, 08191). Making the wafer body in house is what allows two seats, two flange drillings and a coated ball on the same valve.

Quality is certified to ISO 9001, with inspection by Bureau Veritas. Standard sizes are held in stock, the rest built to drawing. The same plant supplies the industrial valve range, with actuators and valve accessories.

Related categories

• Industrial ball valves. The parent category, with all six executions side by side.
• DIN flanged ball valves. Choose them when the valve needs its own flanges in PN16 to PN40, or must come out without separating the pipe flanges.
• ANSI flanged ball valves. Choose them for American specification in class 150 and 300, API 608 cast steel body.
• Metal seated ball valves. The direct sibling of the metal seated wafer, with trunnion and guided ball designs to class 2500.
• Threaded ball valves BSP, NPT and socket weld. Choose them below 2″ (DN50) and at the end of a line.
• Sanitary clamp end ball valves. Choose them for food and pharmaceutical process, 316L bodies and Ra 0.8 µm polish.

Frequently asked questions

Do you manufacture a 25 mm wafer type ball valve?

25 mm is DN25, which is one inch. KTN quotes the wafer execution by DN, so state DN25 together with the flange standard it mounts between, DIN EN 1092 or ANSI B16.5, the class or PN of the line and the seat you need. Body and ball are AISI 316 as standard, and sizes outside the standard range are manufactured to drawing.

Is the wafer ball valve available in stainless steel SS304?

The standard stainless steel wafer ball valve from KTN is built in AISI 316, body and ball, not in 304. The molybdenum in 316 resists chlorides and pitting, which suits the water, desalination and chemical duties this valve normally sees. If a project specifies SS304 or another grade, KTN quotes it to drawing against the fluid and the service conditions.

What are wafer flat body ball valves?

They are ball valves whose body is a flat disc with no flanges machined on it. Both faces are flat and parallel, with a gasket surface around the bore, and the valve is clamped between the two pipe flanges by the through bolts of that joint. The construction gives the shortest face to face and the lowest weight of the ball range.

Can a wafer type ball valve be installed at the end of a line?

No. The wafer body has no flanges of its own, so it needs a mating flange upstream and downstream to be clamped and to seal both gaskets. For a terminal drain, a sampling point or any open end, use a flanged or a threaded ball valve instead. KTN manufactures both executions in the same materials.

What pressure can a high pressure wafer type ball valve take?

With a soft PTFE seat the wafer body covers general service. With a lapped metal to metal seat the same body reaches class 600 and class 900, which is where a 150 lb or a PN160 wafer thin ball valve enquiry usually ends up. Send the design pressure, the temperature and the flange class and KTN confirms the execution.

Wafer ball valve or wafer butterfly valve?

Both mount between flanges. The ball leaves no obturator in the bore when open, so there is no permanent pressure drop, and it seals better as pressure rises because the seat is a full ring around the sphere. The butterfly keeps disc and shaft in the flow but becomes much cheaper per DN in large diameters.