FIELD: mining industry. SUBSTANCE: invention is used in drilling of oil and gas wells. Check valve is provided with member for fixing of threaded bushing which interacts with inner cone bore of threaded ring. Holder has radial protrusions and is fitted with foldable supports on horizontal axles. Cylindrical belt of threaded ring contacts walls of flushing duct. Parts of check valve are manufactured from corrosion-resistant materials. EFFECT: increased durability, prolonged service life, enhanced operational reliability. 2 cl, 1 dwg
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|---|---|---|---|
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