Loaded (plugged)

A filter element that has collected a sufficient quantity of insoluble contaminants such that it can no longer pass its normal-rated flow without excessive differential pressure.

Mean filtration rating

Derived from Bubble Point test method. Data should be used as a guide only to compare overall retention capabilities between fabrics and should not be considered a guarantee of the particle size that the fabric will retain.


A thin polymeric film having pores.

Mesh count

The number of threads in a linear centimeter or inch of fabric/wire cloth.

Mesh geomety

The mesh geometry describes all two- and three-dimensional aspects of the mesh structure. The basic factors in fabric geometry are mesh count and thread diameter.

Mesh number

Indication of number of threads per cm or inch and thread diameter

Mesh opening

Mesh opening is the open area between wires/yarns in the warp and weft direction in the projected plane of the wire mesh.

Mesh tension gauge

Measuring and checking instrument to control the mesh tension. Modern Instruments operate electronically with digital display.

Mesh thickness

The mesh thickness is measured on the unstretched mesh in mm


Single extruded filament


Several monofilaments are bundled together to form a single textile yarn.


A porous web or sheet produced by mechanical, chemical or thermal bonding polymers, fibers or filaments.


The off-contact is the distance between the screen and the substrate before printing, i. e. before the squeegee is pressing down the screen to the substrate.

One circuit stretching system

The one circuit stretching system works pneumatically and is equipped with one control circuit only for all clamps. It is used for screen printing frames with shanks up to approx. 150 cm (also see 'two circuit stretching system').

Open area

The proportion of total screen area that is open space, expressed as a percentage.

Open weave

These fabrics are constructed such that, when viewed at right-angles to their surface, the spaces between the interwoven fibers are visible.


A relatively small subdivision of matter ranging in diameter from a few angstroms (as with gas molecules) to a few millimeters (as with large raindrops). A particle can have various shapes and dimensions.


Ability of a membrane or other material to permit substances to pass through it.

pH value

Used to describe the hydrogen ion concentration of a solution. A pH of 7 is neutral.
Below 7, acidity increases – above 7 alkalinity increases.
The pH value is a non-dimensional figure. It is the negative logarithm of the hydrogen ion activity.

Plain Reverse Dutch weave (PRD)

It has a high thread count in the warp direction and a low thread count in the weft direction.

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Sefar AG

Hinterbissaustrasse 12
9410 Heiden

Phone +41 71 898 5700

Fax +41 71 898 5721

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Filtration & Separation

Screen Printing