Hermetically Sealed: Bursting Discs
If the product you intend to transport needs to be hermetically sealed, you're likely going to need to fit bursting discs. A bursting disc is essentially a safety device that seals the tank to prevent it releasing product or vapours into the atmosphere under normal conditions, and relieves excess pressure in emergency. Depending on the UN code of the product, the transport codes such as ADR and IMDG will state if they are required.
Bursting discs come in various sizes and formats and need to be selected carefully to ensure they operate correctly. A poorly-selected burst disc will not only cost you more in the long term, but will also prematurely fail in service and not serve its intended purpose, compromising the safety of the tank and the surrounding environment.
We have seen it many times when a standard bursting disc has been fitted to an acid tank for example, normally based on its original cost and subsequently corroded/failed on its first load. This obviously leads to frustration, downtime and increased operating costs. Had that disc been selected correctly to begin with, whilst being more expensive initially, the life cycle costs would pay-off, arguably after one load.
When selecting a bursting disc, it is always important to consider the size and set pressure required. However, in addition to this, there are other factors that need to be considered, such as:
Will it be subject to vacuum, for example, when unloading?
The operating ratio. Pressure cycles, pulsation and how high?
Materials of construction to be compatibility with the product in the tank?
An example of where the correct disc selection can make a difference can be seen below. These diagrams show a standard ICON™ and a TOWP ICON™. Although they may look the same to the naked eye, the Teflon liner has been switched to help protect the exposed 316 stainless steel vacuum support, see:
Standard ICON™ Disc
ICON™ TOWP Disc
Although the TOWP disc does add cost, it also provides some additional protection against product corrosion. This, in addition to considering if alternative materials of construction are needed, have a large effect on the performance of the disc.
Continental Disc Corporation® (CDC), a world leader in burst design and manufacture, has a wide range of discs that they provide for multiple applications. The most common supplied to TankPart Limited and our customers are the ICON™, ICON-TL™, PC-SERT™ and TANKSERT™ specifically designed for use on bulk liquid and gas transportable tanks. However, if these weren't suited to your application, there are alternatives such as the HPX® which could be considered.
If you operate bursting discs or have issues with them failing unexpectedly in general service, we can help. We can assist you in selecting the correct disc for your application.
For further information or assistance in the correct selection of burst discs, please contact us at: firstname.lastname@example.org.