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ONIS QLB outperforms traditional blinding methods like spectacle blind, figure-8, slip flange, …

The Quick Action Line Blind (QLB) is a blinding system that is used to isolate or “blind” equipment typically for maintenance or inspection purposes. The technology allows the full blinding operation to be performed in minutes and provides up to 95% reduction in downtime compared to conventional systems such as spectacle blinds. Achieve substantial process improvement using the Quick Action Line Blind with the following key advantages:

Save time


No tool

Green design

Pay back

Convert your loss of production in benefits !

How it works ?

Note: As for the traditional blinding system, before the operation of the ONIS Line blind (QLB), the pipe must be depressurized before starting the blinding operation.

ONIS QUICK ACTION LINE BLIND is a mechanical piping equipment that can guarantee absolute tightness between upstream and downstream pipes whoever is operating it while reducing risks and costs.

Simple and quick to use, this mechanized positive isolation system brings reliability to any positive isolation operation. For all ONIS Quick-Action Line Blinds, the two forged half-bodies / seats spreading operation is performed by a lever or a hand-wheel connected to a gearbox. This flange spreading movement, generated by efficient and reliable synchronized eccentric shafts, allows the displacement of a slide gate designed with a full-bore and a blind position.

Seats clamping movement is as simple as spreading operation. Just oppositely operate the lever or handwheel. This quick-action clamping mechanism is self-locking and resistant to overpressure and vibration.

4 gaskets are only on slide gate 2 per position of use, accessible for inspection or replacement without disassembly.

This positive isolation equipment is set and tested in the factory and requires no adjustment on-site after installation or operation. It enables a pipe isolation with a perfect tightness whoever is going to operate it.


For every projects we have a suitable size range

Diameter up to

Class up to

Min temperature up to

Max temperature up to


  • 1/2″ to 10″ – DN 12 to 250
  • Spreading/tightening of half-bodies by a lever
  • 4 clamping points
  • Slide gate guiding with lifting rollers


  • 10″ to 42″ – DN 250 to 1050
  • Spreading/tightening of half-bodies via a gearbox
  • 4 clamping points
  • Slide gate guiding with lifting rollers


  • > 42″ – > DN 1050
  • Spreading/tightening of half-bodies via a gearbox
  • 6 to 12 clamping points + lateral clamping system
  • Slide gate guiding with lifting rollers

Technical specifications

All Quick Action Line Blind are designed following these specifications:

  • Forged bodies up to 42”.
  • Spreading design with no internal mechanism and no internal gasket.
  • Only four gaskets are located on slide gate: 2 accessible for maintenance during production.
  • Perfect sealings whoever is operating the line blind.
  • Self-locking design.
  • 100 % full bore

Onis Quick Action Line Blind is a patented technology. Indeed, it was designed to guarantees a 100% positive isolation securing your operators, your equipment, and your profitability. Moreover, 100% of Onis Line Blinds are tested in our workshop.


Frequently Asked Questions

How is an ONIS device working ?

A ONIS device is mechanical equipment which permits to one person without any tool to spread the pipe thanks to eccentric shafts in order to permit the sliding movement of the gate equipped or not with accessories.

What range of products can you supply ?

We have manufactured equipment from 1’’ to 52’’, up to 420 bars, from -120°C to +650°C Depends on the devices more information on the product page.

Do ONIS devices are compatible with all types of media ? Gas, fluid, with particles ?

All types of media have been operated with ONIS devices. Fluids, gas-charged media with particles, etc.

Can ONIS Quick Action Line blind replace a valve?

No, a mechanized line blind is not a valve. It is a mechanical device which replaces figure 8 or spectacle blind. A line blind is a real positive isolation device and a valve is not: when a valve leaks, the leak is going downstream into the pipe. With a line blind, it is impossible because upstream and downstream pipes are physically separated with a steel plate. More information on the blog article “Positive Isolation Level of piping.”

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