By Keith Hall
Hoses are an important piece of equipment in the industrial gas sup- ply chain. Used in the delivery and transfer of products, the proper functioning of a hose is very important to industrial gas distributors. When a hose under pressure breaks, it whips around like an angry snake. Product is lost and safety becomes an issue until the system can be safely isolated. In this article, we look at “smart hoses,” equipment with internal shut-off mechanisms that can automatically close off a hose at both ends in the event of a pull-away or severance.
An excess flow valve is one tool that can be included in circuits with hoses to address the break-away problem. Smart-Hose Technologies of Folcroft, PA (www.smarthose.com), manufactures the world’s only industrial hose assembly, which is engineered with internal valves integrated within each end that fits on a hose. Smart-Hoses’ patented safety system is designed
to instantaneously shut down the flow in both directions in the event of a catastrophic hose failure. The system is passive, requiring no human intervention to activate. Smart-Hose Technologies offers hoses for a wide variety of applications including pneumatic and hydraulic operations, cryogenic product delivery or transfer including LNG, and high pressure cylinders.
The Smart-Hose will instantaneously shut down the flow of gas if the hose experiences any one of the following catastrophic failures: the hose separates from the end connection fitting during a transfer operation; the hose gets severed during a transfer operation; the hose ruptures and splits down the side during a transfer operation; or the hose gets stretched to an unsafe condition (but does not break). The Smart-Hose technology causes the internal valves at both ends of the hose to close in the event of a failure, including a rupture that is large enough for the internal cable to push free.
The hose may not always be the weakest link in a pull-away scenario— some hoses make pretty good tow ropes! To address the break-away issue, Smart-Hose engineered a new combination Break-Away Smart-Hose technology. This combination hose has a predetermined breaking-point machined in the fitting at each end, which makes sure the fitting at the end of the hose will break before the hose itself (both ends of the hose also immediately close off). The new Break-Away Smart-Hose is designed to protect personnel and equipment from pull-away incidents and from less obvious but still unsafe incidents, such as a bro- ken hose caused by a high pressure cylinder tipping over.
Tim Raftery, General Manager of Smart-Hose Technologies, says: “Our Smart-Hose system has been in the market for many years. Last April we developed and introduced the two-inch Smart-Hose Break- Away. The break-away is built into the end fitting and works in conjunction with our Smart-Hose system. We are currently developing the Smart-Hose Break-Away in other sizes.”
The Smart-Hose technology meets the new Transport Canada B620 Regulation, which requires off-truck remote or passive emergency discharge systems for highway tanks or portable tanks during the loading or unloading of LP Gas or anydrous ammonia. Smart-Hose assemblies are CSA approved.
It is recommended that Smart-Hoses, or Smart-Hoses with Break- Away fittings, be mounted or installed at 45 or 90 degrees to horizontal for several reasons. First, failure is due to shearing forces and a hose is much stronger when pulled in direct tension. Therefore, you want the hose assembly mounted at an angle so that it is the weakest link and will break-away first in a drive-away scenario. Second, if a facility experiences an accidental release while utilizing a 45 or 90 degree hose port, the hazardous product released will be directed towards the ground and not directly at the operator. Third, during nor- mal usage, a 45 or 90 degree hose port removes most of the bending stress from the hose where it attaches to the end connection as the weight of a hose causes it to sag. Like an electrical cord, hoses tend to kink and break at their end connections.
Keith Hall is the Engineering Manager of INOXCVA’s Cryogenic Vessel Alternatives’ LNG/Specialty Products Division in Mont Belvieu, TX, and can be reached at firstname.lastname@example.org.