Frequently Asked Questions

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.

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.

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 which are based on ASME VIII pressure vessel code.

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.

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.

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.

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.

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

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

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

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

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.”

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

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

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.”

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

ONIS technology does not need any appreciation on the part of the operator: The ONIS design is set up in our workshop for the entire life cycle to guarantee the tightness.