Mining roof support cylinder corrosion protection apparatus and method

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.

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.    
   
   
       2 . 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.    
   
   
       3 . 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.  
   
   
       4 . The method in accordance with  claim 2  wherein the non-corrosive gas is nitrogen.  
   
   
       5 . 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.  
   
   
       6 . The method in accordance with  claim 2  further comprising a step of continuous flushing of said enclosure with the non-corrosive gas.  
   
   
       7 . 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.  
   
   
       8 . The method in accordance with  claim 2  further comprising continuous flushing of corrosive gas away from said metallic parts.  
   
   
       9 . 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.  
   
   
       10 . 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.  
   
   
       11 . 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.  
   
   
       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.    
   
   
       13 . A roof support for an underground mine in accordance with  claim 12 , wherein said non-corrosive gas is nitrogen.  
   
   
       14 . 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.  
   
   
       15 . 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.  
   
   
       16 . A roof support for an underground mine in accordance with  claim 12 , wherein surfaces of said hydraulic cylinder are plated with bronze.  
   
   
       17 . 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.  
   
   
       18 . 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.  
   
   
       19 . 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.  
   
   
       20 . 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.  
   
   
       21 . 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.