Allspeeds launches ROV-mounted cut loop cutter for BOPs
Working with blow-out preventers (BOPs), reliability and redundancy tend to be the watchwords. But in the event of failure or emergency, back-up solutions have to be even more robust.
One such option is subsea intervention. This uses remotely operated tools to prevent a blowout once all control or topside solutions have failed to work. In many instances, that redundancy is a cut loop which, when severed, prevents pressure lock in the hydraulic system needed to activate the BOP.
As a result, these loop cutters need to be robust and reliable. One such device has recently been produced by hydraulic cutters and systems specialist Allspeeds. Its newest ROV-mounted Webtool cut loop cutter – the smallest hydraulic guillotine cutter in the range – is designed to sever the cutting loop and activate the BOP in the event other measures have failed.
During intervention, the Webtool cutter is held in position over the cut loop by an ROV in case of an emergency situation. The wide mouth and open-sided design of the Webtool cutter should allow for the tool to be positioned on the stainless steel, hydraulic cut loop pipe with ease.
The blade has been optimised for cutting stainless steel tube and developed so the cut loop will fully release pressure immediately after the cutter is activated. The unit is built with a corrosion-resistant stainless steel body and cylinder.
The Webtool cutter can be used at any water depth, with pressure compensation on the hydraulic supply. Weighing 7kg in water, the cutter uses 700bar maximum input pressure, although an optional hydraulic intensifier is available. Allspeed’s Webtool range includes a number of cable, rope and line cutters, for mounting in various locations, including ROVs. As the smallest tool in the range, this design is particularly useful for operation in confined spaces.
Fittingly, the company’s smallest cut loop cutter follows the production of its largest rope cutter, unveiled in August 2016. The Webtool SL165 softline ROV tool is capable of cutting soft and fibre ropes up to 165mm diameter. It can be deployed either on the manipulator arm of a work-class ROV or integrated within a maritime handling system, with both working at any water depth.
Fibre rope is widely used in subsea anchoring, equipment deployment and construction as an alternative to steel wire. The need to handle higher loads has prompted the use of larger diameter ropes. In the event that these ropes need to be cut, the Webtool guillotine will sever softline within a few seconds.
Made from lightweight aluminium, the Webtool SL165 weighs 49.8 kg in air (33.5 kg in water) and uses 690 bar maximum input pressure.
The SL165’s corrosion-resistant aluminium body and cylinder and long blade and anvil life ensures tool maintenance is kept to a minimum. In addition to the standard tool design, the company can also supply the softline cutter in bespoke and custom designs to suit special applications, with the possibility of cutting softlines up to 350mm and more.