Rupture disk in series with safety relief valve


Thread Starter


We have an application where argon is supplied from different banks of argon cylinder to the various supply points. we reduce the pressure
before sending it to the supply points. Safety relief valve is kept as a safety device but we found safety relief valve is passing and is
not leak tight.

In that context if we need to arrest the passing through the safety valve, whether a rupture disk in series with safety relief valve would

A rupture disk followed by relief valve is often used where no leakage can be tolerated. This is standard for corrosive gases like SO2. Most rupture disk or relief valve manufacturers should be able to give you more information.
This is a very common practice in the Chemical industry. I'm currently working on an SO2 tank installation where the rupture disc/relief
valve is used. The rupture disk must be placed "upstream" of the PSV, and an indicator should be used on the rupture disc to indicate when it's "blown". (I know of a chemical plant that did not have indication where several tons of ethylene were lost over a period of months
because no one knew it was blown!) A pressure switch between the disc and the PSV is a simple way of detecting failure.

Relief valves close when their job is completed, rupture disks don't. What is the implication of this to your process? If both are in series, the
relief valve may not work properly. Why is the relief valve leaking, and can that problem be corrected?


I have come across several cases when Rupture Disks are used in series with Safety Relief valves. The Safety Relief valve capacity will need to be de-rated as per the applicable code.
Make sure you have a 'Tell tale' assembly or a pressure switch which serves as an indication that the Rupture disk has not burst. Due to 'Burst Pressure' tolerances, the safety relief valve set pressure needs to be
sufficiently distinct. The Rupture Disc assembly also has to be suitable to be mounted in series with the safety valve. Due to manufacturing requirements, Rupture Discs normally are sold as a 'Lot' of three or four pieces at a time. You can't buy a single Rupture Disk off the shelf.

Consult both safety valve rupture disk manufacturers before actually purchasing anything.


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Dear Mr Vijay,

Adding a rupture disc would not help.

Please check the set point of the Safety Relief Valve. This is purely the case of malfunctioning of the Safety Relief Valve.
Hai Vijay,

the rupture disk in series with the saftey releif valve s follws.

The saftey valve, abobe the saftey vale rupture disk, below the saftey valve pressure switch.

Here you can use the rupture disk is made with thick paper, and a metal foil (conductor very thinh )will be placed on the centre of the
paper. Once saftey releief valve blows the the paper made rupture disk brakes , & it also brakes the thin metal foil on the top the paper rupture. You will disconnect from the circuit. The normally closed circuit and and normally open cicuit will detect your PLC or DCS through a sinking principle, will allow the alarming or stopping the process.

Once the safety releif valve not operates , the rupture disk can not brake, the pressure switch will act and alraming the process or stop the process.

You can do pressure switch, roupture disk and releief valve in series also. Its depends upon the how serious it is, if it brakes you need to stop complete process to fix the same

In general, normally closed contact will took this kind of the applications, to avoid any cable brakings and saftey point of view.


mullpudi r
This is a very common rupture disk application. Safety relief valves tend to chatter when used near their set pressure. Putting a rupture disk under the valve eliminates that problem. It also offers the advantage of protecting an expensive safety valve from corrosion - although this clearly doesn't apply in your case.

Please see our web site at "": for information. You can contact our technical people at 918-258-5626 as well.

Good luck.
While I commend the author's ingenuity, there's an easier and safer way to do this. All reputable rupture disk vendors sell pre-made sensors. The sensor needs to be properly designed, considering the rated burst pressure of the disk and flow conditions, to ensure safe operation. Contact your rupture disk vendor or see "": for information on sensors.