发明授权
US07798171B2 Valve assembly 有权
阀组件

Valve assembly
摘要:
The present invention relates to a valve having a first assembly cooperating with a second assembly to create a seal, wherein the first assembly opens before the second assembly opens and closes after the second assembly closes. The invention also relates to a valve wherein the pressure required to open the second assembly is greater than the pressure required to open the first assembly.
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