New continuity tester for hoses in combustible atmospheres
The OhmGuard hose continuity tester, manufactured by Newson Gale, is designed to ensure that a string of assembled hoses have good electrical continuity with a grounded truck ensuring electrostatic charges cannot accumulate on the metal components of the hoses being used in the transfer operation.
During hazardous area tank cleaning, spill recovery and product delivery operations vacuum trucks and bulk road tanker trucks are regularly exposed to the ignition hazards of static electricity.
Newson Gale believes, while it is vitally important to ground the vehicles used in the transfer operation, it is also important to ensure the hoses used to transfer product into, or out of, the vehicle cannot accumulate static electricity: ‘Electrically isolated metal components, like hose couplings and wire helixes, have the potential to accumulate enough static electricity to discharge a high energy spark into a combustible atmosphere.’
The OhmGuard operates on the principal of a “pass or fail” test procedure. To operate the device, the driver will first ground the truck and then assemble the required number of hose sections to the truck. The driver will then connect the OhmGuard clamp to the free coupling or nozzle of the last hose (see illustration). If the electrical resistance through the string of hoses to the grounded truck is “good”, a green LED mounted in the OhmGuard clamp will pulse continuously informing the driver that the hoses are bonded to the truck and are safe to use. If there is a break in continuity, the LED will not pulse and the driver may carry out a quick visual inspection of the hoses to ensure parts like wire helixes have not suffered broken connections with components like end couplings. The driver may also elect to test each hose individually.
The OhmGuard carries cCSAus, ATEX and IECEx approvals for operation in the highest combustible gas, vapour and dust atmospheres.