Group

Glossary

Surface media

Captures particles on the upstream surface with greater efficiency than depth media, sometimes close to 100% and with minimal or no off-loading. Commonly rated according to the smallest particle the media can repeatedly capture. Examples of surface media include ceramic media, microporous membranes, synthetic woven screening media and, in certain cases, wire cloth. The media characteristically has a narrow pore size distribution.

Surface resistivity ( Ω/n)

Expressed in ohms/square. It is numerically equal to the resistance between two electrodes forming opposite sides of a square on the surface of a material. The size of the square is irrelevant. For conductive materials, surface resistivity is the ratio of the volume resistivity to the fabric thickness (r/t).

Taffeta weave

Plain weave

Tangential cross-flow filtration

Process where the feed stream 'sweeps' the membrane surface and the particulate debris is expelled, thus extending filter life. The filtrate flows through the membrane. Most commonly used in the separation of high and low molecular weight matter in such applications as ultrapure reverse osmosis, ultra-filtration, and submicron microfiltration processes.

Tensocheck 100

Digital tension measuring instrument by Sefar

Textured yarn

A yarn that has been geometrically altered to increase bulk or moisture absorption, add resiliency, etc.

Theoretical ink volume Vth

Calculated Value of the ink volume 'Vth' from open area ('ao') in % and the mesh thickness 'D' in mm:
Vth = ao x D/100

Thread count

See 'Mesh count'

Thread diameter

The thread diameter respectively thread thickness is specified as nominal value, referring to the diameter of the raw and unwoven thread in mm.

Throughput

The amount of solution that will pass through a filter prior to it becoming clogged.

Twill weave

Formed by passing the warp or weft fiber over two or more fibers.

Twist

Turns imparted to a length of yarn. Usually expressed in tpi
(turns per inch).

Two circuit stretching system

A two circuit stretching system works pneumatically and is equipped with two independent air circuit controls, one each for the parallel frame shanks. It is used for frames with shanks exceeding 150 cm (see also 'one circuit stretching system')

Ultrasonic (processes)

Process that utilizes specially-designed tooling usually vibrating at 15 – 80 kHz. Processes are designed to cause localized heating of thermoplastic materials that will cause some type of welded or fused joint to form. Benefits are the elimination of fillers and minimized heat stress on surrounding materials.

Undercutting

Light rays striking the white fibers of the mesh are reflected and scatter under the edges of the film.
Light is also conducted through the fibers leading to yet more undercutting. Result: blurred edges, colour shifts. Sefar yellow dyed mesh prevents undercutting.

Upstream side

The feed side of a filter.

Volume resistivity

Or specific resistivity of a material, expressed in W.cm. Resistance to electrical current flow through the bulk of an object.

Warp

Fibers or wires running the length of the cloth as woven.

Weft

Fibers or wires running across the width of the cloth as woven.

Wicking

The rapid movement of moisture along the fiber surface, usually by capillary action.

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Sefar AG

Headquarters
Hinterbissaustrasse 12
9410 Heiden
Switzerland

Phone +41 71 898 5700

Fax +41 71 898 5721

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