Patent ID: 8291984
Filing Date: 2012-10-23
Classification: E21B

Abstract:
1. A control device for a tool in the form of an inflatable bladder for the treatment of a well or a pipe, which is connected to a single pressurised fluid feed conduit, and positioned between an output of the conduit and a ferrule attached to the tool, through which entry and exit of fluid is controlled in order to control inflation and deflation of the bladder, the control device comprising an enclosure within which is located a piston driven by a spring, the enclosure communicating with an exterior of the device, firstly by means of a tube or bleed orifice, and secondly via at least one pipe, said ferrule, said piston and said enclosure being arranged so that: said piston normally occupies a first position, under action of said spring, in which it closes off the output of said feed conduit, with said tube or bleed orifice communicating with said pipe via chambers of the enclosure; wherein, when pressure generated by the fluid present in said feed conduit exceeds a specified threshold value, said piston is moved against said spring so that it occupies a second position, in which said tube or bleed orifice is isolated, while said feed conduit communicates with said pipe via at least one of the chambers of the enclosure, and wherein said pipe is fitted with at least one first non- return valve, with a pre-loaded spring, which allows the passage of the pressurised fluid from one of the enclosures to the tool when pressure upstream of the valve exceeds a specified threshold value, and only in this case, and that prohibits the passage of the fluid in an opposing direction.