# US 2006/0214496 A1 · Mining roof support cylinder corrosion protection apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2006/0214496 A1 - Document ID: US20060214496A1 - Status: Published application - Kind: A1 - Application number: 11/085,218 - Filed: 2005-03-22 - Published: 2006-09-28 - Earliest claimed: 2005-03-22 - Assignees: Avistar, Inc. - Inventors: Lawrence Randlett; Steven Willard - Web page: https://patentgrep.com/patent/US20060214496A1 ## CPC - E21D 23/03: having protective means, e.g. shields, for preventing or impeding entry of loose material into the working space or support - E21D: SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS (soil-conditioning or soil-stabilising materials C09K17/00; drilling or cutting machines for mining or quarrying E21C; safety devices, transport, rescue, ventilation or drainage E21F) ## Abstract A roof support for an underground mine which has a hydraulic cylinder positioned between a roof engaging support and a ground engaging base and has a flexible gas barrier or enclosure surrounding surfaces of said hydraulic cylinder which are subject to corrosion by gases present in the underground mine. Continuous flowing non-corrosive gas such as nitrogen is supplied to a space between the gas barrier and said hydraulic cylinder for preventing corrosion of cylinder surfaces by corrosive gases present in the mine which may include hydrogen sulfide. ## Claims ### Claim 1 A method for protection of exposed metal surfaces in a coal mine comprising the steps of: placing parts in the coal mine having a corrosive gas; and creating a non-corrosive environment immediately adjacent to corrosion sensitive parts. ### Claim 2 (depends on 1) The method in accordance with claim 1 further comprising the step of creating a non-corrosive environment comprises the steps of: placing said parts in an enclosure; and introducing a continuous flow of a non-corrosive gas into the enclosure. ### Claim 3 (depends on 1) The method in accordance with claim 1 wherein said corrosive gas includes hydrogen sulfide and said parts have exposed metal surfaces containing copper based alloy. ### Claim 4 (depends on 2) The method in accordance with claim 2 wherein the non-corrosive gas is nitrogen. ### Claim 5 (depends on 2) The method in accordance with claim 2 further comprising the step of introducing the non-corrosive gas at a positive pressure with respect to an ambient pressure in said coal mine. ### Claim 6 (depends on 2) The method in accordance with claim 2 further comprising a step of continuous flushing of said enclosure with the non-corrosive gas. ### Claim 7 (depends on 2) The method in accordance with claim 2 further comprising enclosing said metallic parts in a plastic or other flexible container having seals along at least one side and at least one opening at an end which allows a flow of non-corrosive gas to escape. ### Claim 8 (depends on 2) The method in accordance with claim 2 further comprising continuous flushing of corrosive gas away from said metallic parts. ### Claim 9 (depends on 7) The method in accordance with claim 7 further comprising sealing at least one end with flange seals and attaching a nitrogen or other non-corrosive gas source to said enclosure. ### Claim 10 (depends on 2) The method in accordance with claim 2 further comprising a fixed or an adjustable exhaust port to maintain a positive pressure within said enclosure with respect to ambient conditions. ### Claim 11 (depends on 2) The method in accordance with claim 2 further comprising the step of maintaining a flow of the non-corrosive gas into and out of the enclosure by controlling pressure of incoming non-corrosive gas and sizing of an outlet opening fixed size or adjustable exhaust port. ### Claim 12 A roof support for an underground mine comprising in combination: a roof engaging support; a ground engaging base; at least one hydraulic cylinder positioned between said roof engaging support and said ground engaging base; a flexible gas barrier surrounding surfaces of said hydraulic cylinder which are subject to corrosion by gases present in said underground mine; and a non-corrosive gas supply for supplying a non-corrosive gas to a space between said gas barrier and said hydraulic cylinder. ### Claim 13 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein said non-corrosive gas is nitrogen. ### Claim 14 (depends on 12) A roof support for an underground mine in accordance with claim 12, further comprising a pressure release or exhaust orifice for creating and regulating a positive pressure within said gas barrier with respect to ambient pressure when non-corrosive gas is supplied to said space. ### Claim 15 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein said gasses present in said underground mine which cause corrosion include hydrogen sulfide. ### Claim 16 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein surfaces of said hydraulic cylinder are plated with bronze. ### Claim 17 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein said non-corrosive gas is supplied from a nitrogen gas supply used to reduce the hazard of spontaneous combustion of coal in the mine. ### Claim 18 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein there are at least two hydraulic cylinders positioned between said roof engaging support and said ground engaging base. ### Claim 19 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein surfaces of said hydraulic cylinder which are subject to corrosion by gases present in said underground mine are outer surfaces of lower cylinders and upper cylinders of a two cylinder hydraulic cylinder. ### Claim 20 (depends on 12) A roof support for an underground mine in accordance with claim 12, wherein said gas barrier or enclosure comprises a flexible gas barrier which is attached to a lower cylinder and an upper cylinder of said at least one hydraulic cylinder. ### Claim 21 (depends on 14) A roof support for an underground mine in accordance with claim 14, wherein said pressure release or exhaust orifice is attached to a flange which is attached to said cylinder and said gas barrier.