System and Method of Sealing Process Leaks

Abstract

A system and method of sealing leaks in process piping and equipment without process shutdown by providing a clamp having a cavity surrounding a leaking structure, sealant equipment comprising an injection gun to inject a sealant into the clamp cavity, means for pressuring moldable sealant from the gun into the clamp cavity in a staged manner beginning at a point away from the leak site. The preferred sealant comprises a moldable nitrile rubber delayed curing (vulcanizing) formulation or composition molded into shapes for insertion into an injection gun.

1 . A system for sealing leaks in process piping and equipment comprising, a clamp that surrounds the leak site and provides a cavity that surrounds the pipe or equipment to be sealed and has at least two ports into which sealant can be injected, an injection gun having at one end an injection port capable of mating with the clamp ports, a chamber communicating with said injection port for receiving a shaped sealant compound, a piston chamber, a piston capable of pushing the sealant through the injection port and a means for actuating the piston, a conduit between the injection gun piston chamber and a hydraulic or pneumatic pump for applying force to push the piston toward the sealant chamber and a shaped delayed curing sealant composition. 
     
     
         2 . The system of  claim 1  wherein the clamp is made of steel and comprises two halves with flange ears and bolt holes for removably attaching said clamp around a leaking pipe or structure, the internal dimensions of said clamp being larger than the outside dimension of the structure so that there is a cavity between the clamp and structure completely surrounding said structure. 
     
     
         3 . The system of  claim 1  wherein the clamp is a steel band that surrounds the opening between flange ears and the clamp ports comprise bolt holes in the flange. 
     
     
         4 . The system of  claim 1  wherein the sealant comprises; an extrudable delayed curing nitrile rubber composition comprising a nitrile rubber, a sulfur compound capable of cross linking the nitrile rubber, an accelerant, an activator, a filler, a plasticizer, a flame retardant and metallic filament all compounded in dry un-reacted form and wherein the nitrile rubber is in the composition is preconditioned for sufficient to increase plasticity prior to compounding with the other components of the composition. 
     
     
         5 . The system of  claim 4  wherein the sealant composition is molded to form cylinders of about 20 mm diameter and about 90 mm long and the clamp ports will be about 5-15 mm diameter. 
     
     
         6 . The system of  claim 4  wherein the sealant composition comprises, by weight: 10-20% preconditioned acycronile-butadene rubber; 0.3 to 0.5% sulfur; 6 to 12% crosslinking compounds and fire retardant agents selected from the group consisting of diantimony trioxide, and chlorcosane; 1 to 6% accelerant selected from the group consisting of n-cyclohexyl-2-benzothizole-sultenamide, 2-mercaptobenzothiazole and 2-dibenzothiazole disulfide or a combination thereof; 3 to 8% zinc oxide and/or stearic acid activators; 50 to 60% total fillers selected from the group consisting of iron oxide, talcum powder, graphite, semi-reinforcing carbon black, clay, and combinations thereof; 10 to 20% plasticizer; 0-2% rare earth nanophase material; 2 to 5% antidegradant; and 2 to 5% metallic filament. 
     
     
         7 . The system of  claim 1  wherein the sealant is comprised of a Teflon R  or epoxy resin based formulation. 
     
     
         8 . A method of sealing leaks in process pipes and structures comprising; placing a suitable clamp having dimensions that leave a cavity between the inside of the clamp and the pipe or structure, said clamp having at least two ports positioned around the surface of the clamp, connecting an injection gun through an injection port to a port of the clamp, placing delayed curing sealing compound into the injection gun, actuating a piston in the injection gun to force the sealant through the injection port and clamp port into the cavity of the clamp. 
     
     
         9 . The method of  claim 8  wherein the cavity between the outside of the leaking structure and the inside of the clamp is from about 5 m to 20 mm in width from outside diameter of the pipe to the inside surface of the clamp. 
     
     
         10 . The method of  claim 8  wherein the sealant is injected into a port on a clamp in sequence, beginning with the port the greatest from the site of the leak and adding sealant to ports away from the leak site ending with sealant in a port nearest the leak site. 
     
     
         11 . The method of  claim 8  wherein the clamp is made of steel and comprises two halves with flange ears and bolt holes for removably attaching said clamp around a leaking pipe or structure, the internal dimensions of said clamp being larger than the outside dimension of the structure so that there is a cavity between the clamp and structure completely surrounding said structure and the sealant is a delayed curing nitrile formulation. 
     
     
         12 . The method of  claim 8  wherein the sealant composition comprises, by weight: 10-20% preconditioned acycronile-butadene rubber; 0.3 to 0.5% sulfur; 6 to 12% crosslinking compounds and fire retardant agents selected from the group consisting of diantimony trioxide, and chlorcosane; 1 to 6% accelerant selected from the group consisting of n-cyclohexyl-2-benzothizole-sultenamide, 2-mercaptobenzothiazole and 2-dibenzothiazole disulfide or a combination thereof; 3 to 8% zinc oxide and/or stearic acid activators; 50 to 60% total fillers selected from the group consisting of iron oxide, talcum powder, graphite, semi-reinforcing carbon black, clay, and combinations thereof; 10 to 20% plasticizer; 0-2% rare earth nanophase material; 2 to 5% antidegradant; and 2 to 5% metallic filament.