초록 ▼

Described herein is a pressure relief valve that vents contents from a rail tank car or similar container at two preset pressures. The lower preset pressure is attained whenever specific valve attachment devices melt well below the spontaneous combustion temperature of the contents of a rail tank ca

Described herein is a pressure relief valve that vents contents from a rail tank car or similar container at two preset pressures. The lower preset pressure is attained whenever specific valve attachment devices melt well below the spontaneous combustion temperature of the contents of a rail tank car or similar container. When these attachment devices melt, formerly attached corresponding constant force spring assemblies disconnect from a spring plate. Without these operative attached spring assemblies there is less force to oppose the pressure from the contents of rail tank car or similar container. With less opposing force, the contents of the rail tank car or similar container escape from under a dislodged sealing disk before the rail tank car or similar container (i) over pressurizes and causes the tank shell to fail or (ii) the contents self-combust, and both of which events cause an explosion.

대표청구항 ▼

1. A dual preset pressure relief valve comprising valve components by which said pressure relief valve can relieve pressure from contents within a rail tank car or closed container or at a first temperature and a second temperature, said valve components comprising constant force spring assemblies,

1. A dual preset pressure relief valve comprising valve components by which said pressure relief valve can relieve pressure from contents within a rail tank car or closed container or at a first temperature and a second temperature, said valve components comprising constant force spring assemblies, a spring plate and mechanical attaching components,said mechanical attaching components attaching said constant force spring assemblies to said spring plate, said mechanical attaching components comprising a first plurality and a second plurality,said second temperature being the melting temperature of a second material, said second plurality of said mechanical attaching components comprising said second material,said melting temperature of said second material being lower than the melting temperature of said first plurality,said second plurality disconnecting from said spring plate and said constant force spring assemblies at said melting temperature of said second material,said first plurality remaining connected to said spring plate and said constant force spring assemblies at said melting temperature of said second material. 2. The dual preset pressure relief valve of claim 1 further comprising a valve flange with an upper surface, said valve further comprising spring brackets and spring drums, each said spring bracket comprising a first stepped spring bracket panel and a second straight spring bracket panel, said first stepped spring bracket panel comprising a vertical stepped structure,said first stepped spring bracket panel supporting at least three linearly aligned said constant force spring assemblies, wherein two said first stepped spring bracket panels adjoin each other along said valve upper surface,said at least three linearly aligned said constant force spring assemblies containing a single inserted first spring drum of a first longitudinal length, each said first spring druminserting within said two adjacent first stepped spring bracket panels,said second straight spring bracket panel comprising a straight vertical structure,said second straight spring bracket panel supporting two linearly aligned constant force spring assemblies, and wherein two said second spring bracket panels adjoin each other along said valve upper surface,said two linearly aligned said constant force spring assemblies containing a single inserted second spring drum of a second longitudinal length, each second spring drum inserting within two adjacent said second straight spring bracket panels, andeach said second spring drum being of a lesser longitudinal length than each said first spring drum. 3. The dual preset pressure relief valve of claim 1 wherein said second plurality of said mechanical attaching components comprises bolts, said bolts comprising glass filled nylon. 4. The dual preset pressure relief valve of claim 1 wherein more than one-half of said mechanical attaching components comprise said second material, said valve comprising more than eight said constant force spring assemblies. 5. The dual preset pressure relief valve of claim 1 wherein said second plurality of said mechanical attaching components comprises a first portion and a second portion of said mechanical attaching components, said spring plate comprising a first pair of opposing sides and a second pair of opposing spring plate sides,said first portion of said second plurality of said mechanical attaching components opposing each other across said first pair of said opposing spring plate sides,said second portion of said second plurality of said mechanical attaching components opposing each other across said second pair of said opposing spring plate sides, andsaid first plurality of said mechanical attaching components attaching to said first pair of said opposing spring plate sides. 6. The dual preset pressure relief valve of claim 1 wherein each said constant force spring assembly comprising seven to ten leaves. 7. The dual preset pressure relief valve of claim 1 wherein said spring plate comprises a four sided polygon, said second plurality of said mechanical attaching components aligning along all said sides of said spring plate, said second plurality melting at a lower temperature than said first plurality of said mechanical attaching components. 8. The dual preset pressure relief valve of claim 1 wherein said valve comprises a spiral spring retaining ring within a removable sealing disk in combination with a flexible circular seal, said removable sealing disk comprising a solid integral circular component, said removable sealing disk comprising a single lower sealing disk circular surface and a single upper disk circular surface, said lower sealing disk circular surface being conical in configuration,said lower sealing disk circular surface comprising a single circular continuous circular sealing disk channel and a single continuous circular sealing disk channel lip,said lower circular sealing disk channel and said circular sealing disk channel lip being contiguous with each other,said flexible circular seal snugly and continuously lodged with said single sealing disk lower channel,said spiral spring retaining ring inserting into said sealing disk circular channel lip. 9. The dual preset pressure relief valve of claim 1 wherein said mechanical attaching components attach sets of three linearly aligned constant force spring assemblies to said spring plate, each said set comprising two said constant force spring assemblies attaching to said spring plate with said second plurality of mechanical attaching components, andeach said set comprising a single constant force spring assembly attaching to said spring plate with said first plurality of said mechanical attaching components. 10. The dual preset pressure relief valve of claim 1 wherein a portion of said constant force spring assemblies are linearly aligned within sets of three said constant force spring assemblies, and wherein two said linearly aligned constant force spring assemblies within each said set attach to said spring plate with four of said second plurality of said mechanical attaching devices,and wherein the centrally positioned constant force spring assembly attaches to said spring plate with two of said first plurality of said mechanical attaching devices. 11. The dual preset pressure relief valve of claim 1 wherein said valve comprises spring drums and a first plurality of vertical spring brackets and a second plurality of vertical spring brackets, said first plurality of said vertical spring brackets supporting three constant force spring assemblies along a corresponding said spring drum,said second plurality of said vertical spring bracket supporting two constant force spring assemblies along a corresponding said spring drum. 12. The dual preset pressure relief valve of claim 1 wherein said first plurality of said mechanical fastening components consists of metal. 13. The dual preset pressure relief valve of claim 1 wherein each said constant force spring assembly is approximately two inches in width. 14. The dual preset pressure relief valve of claim 1 comprising ten constant force spring assemblies, and each said constant force spring assembly being approximately two inches in width. 15. The pressure relief valve of claim 1 wherein said constant force spring assemblies create an opposing pressure, said second plurality of said mechanical attaching components melting at a temperature that minimizes said opposing pressure by disconnecting said constant force spring assemblies from said spring plate,said mechanical attaching components thereby preventing said pressure relief valve from achieving a maximum opposing pressure. 16. The pressure relief valve of claim 1, said pressure relief valve not comprising adhesives. 17. The dual preset pressure relief valve of claim 1 further comprising a valve flange with an upper surface, said valve further comprising spring brackets along said upper surface, each said spring bracket comprising a first stepped spring bracket panel and a second straight spring bracket panel,said first stepped spring bracket panel comprising a vertical stepped structure,said first stepped spring bracket panel supporting at least three linearly aligned said constant force spring assemblies, and wherein two said first stepped spring block panels adjoin each other along said valve upper surface,said second spring bracket panel comprising a straight vertical structure,said second spring bracket panel supporting no more than two linearly aligned constant force spring assemblies, and wherein two said second spring bracket panels adjoin each other along said valve upper surface.