FAQ

Frequently Asked Questions

How is an ONIS device working ?

An ONIS device is mechanical equipment that permits one person without any tool to spread the pipe thanks to eccentric shafts to permit the sliding movement of the gate equipped or not with accessories. More information on the “Concept & product” page and our media center.

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 Depending on the device’s information on the product page.

What are the applied standards to ONIS devices ?

There is no specific standard for designing and manufacturing mechanized line blinds or ONIS devices. Flange to flange dimensions are specific and function of calculation results are based on ASME VIII pressure vessel code.

What is the frequency for changing the seals ?

Generally speaking, a first approach is to consider at least one seal replacement per year.
The frequency of change is related to the conditions of service, proper handling of the device, and its frequency of use.

Do the Onis seals are specific or can be found easily ?

The quality of the seals (dimensions and composition) depends on the tightness of the ONIS device. For safety reasons, it is warmly recommended to only use ONIS spare parts for ONIS devices.

During spreading of the ONIS device, is there any stress for pipes ? What if the pipe is already stressed ?

One inch / 25 mm is required by the traditional blinding method. With ONIS is an average of 5 mm. Force generated by the ONIS line blind is 10 times less than for the traditional method. By design, the arm lever generated by ONIS mechanical parts is very important. Operated by a lever or handwheel one operator will be able to do blinding operation even it is for a #2500 rating class.

What is the maintenance needed?

Only the 4 seals have to be changed when they are damaged. ONIS’s recommendation is to inject grease in grease fittings at least once a year. Out of that, there is no specific maintenance.

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.

Do the blinds remain permanently in the pipe?

Yes ONIS is definitely installed on pipes even if temporary installations could be imagined for very specific uses as mobile scrapping units.

How manage the pipe's depressurization if upstream or downstream valves are close to ONIS device ?

ONIS devices can be supplied with integrated drain ports already drilled into a flange or half bodies. ONIS D3B device is -equipped by design with bleeder ports -permits to have the smallest dead volume the valves and the line blinds.

What is a ONIS Line blind lifespan ?

It depends on the environment mainly but we can say that some ONIS have been installed in 1979 and are still in operation. The reliability of ONIS line blinds has been proved after more than 40 years.

Can ONIS Quick Action Line blind replace a valve?

No, a mechanized line blind is not a valve. It is a mechanical device that 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 blog “Positive Isolation Level of piping”

How can I be sure that there is no risk when I operate an Onis?

Different levels of safety are available: from operator’s training to safety optional devices such as safety locks, pressure gauge, ONIS engineer can support you to choose the best solutions, to sum up within HiSafe range products line which is a specific line dedicated to reducing the human factors.

Do we need to depressurize the pipe before operating an ONIS device ?

As for a traditional blinding operation, safety requirements are the same. Only the way and the time requested to open the pipe to the atmosphere is very reduced. Please have a look at the video “How to operate a line blind” on the media center page

Can you provide a solution without opening to the atmosphere?

It is not the philosophy of ONIS products because it is no more positive isolation. Indeed, in case of failure of the slide gate’s sealing, the risk is to have a leak from upstream to downstream and so to have non-safe isolation. Please have a look at “The different level of isolation.”

Do the ONIS line blinds are fire safe design ?

Yes, a fire-safe design is available.
Even if API 607 does not apply strictly to ONIS line blinds, ONIS company is equipped with its fire test bench and all the tests have been followed by a third part SGS or DNV.

What makes ONIS technology unique ?

No appreciation by the operator: ONIS design is set in our workshop for all lifespans to guarantee tightness.