| 摘要 |
The invention relates to a safety valve sensitive to the pressure prevailing in the annular space of an underground well. The valve is fully opened in order to allow complete access, through it, for cables and other operating tools. It contains valve elements which are entirely offset from the central cylindrical body. The elements of the valve can be actuated under the effect of a progressive rise in the pressure which is applied to them. Field of application: safety devices for oil and gas wells, etc. <IMAGE>
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