| 摘要 |
construction and manufacture of shut-off fittings for pipe lines. SUBSTANCE: according to first version, proposed cock has body, shut-off member, seat stem and sealing unit of stem where shut-off member is made integral with stem and sealing unit; sealing unit of stem is made in form of truncated cone whose larger base is directed downward; stem is arranged coaxially inside this cone; lower portion of truncated cone is engaged with upper portion of working outer surface of revolution of shut-off member; besides that, shut-off member, stem and sealing unit are from one plastic material and body integral with seat is made from other plastic material; thermal expansion coefficient of second plastic material of body with seat exceeds that of first plastic material of shut-off member with stem and sealing unit of this stem. According to second version, proposed cock with swivel plug includes shut-off member made integral with stem from one and the same first plastic material in form of inverted truncated cone; outer surface of stem is provided in its portion engaged with wall of hole in body either with circular recess or with circular projection of steam sealing unit; body is made integral with seat from one and the same second plastic material; wall of hole in body engaged with stem is provided respectively either with mating circular projection or mating circular recess of stem sealing unit; thermal expansion coefficient of second plastic material of body with seat exceeds that of first plastic material of shut-off member with stem. Two versions of manufacture of cock are proposed; according to first version, shut-off member is manufacture in first matrix; stem and its sealing unit is made in form of single insertion part; to this end, first plastic material, for example fluoroplastic 40 at temperature of 350 C is poured into matrix, after which matrix is cooled down together with insertion part to be molded and then assembly of cock is performed simultaneously with manufacture of body and seat; to this end, premolded single insertion part "shut-off member + stem + sealing unit" is placed in second matrix and is filled with second plastic material, for example polypropylene BALEN at temperature of from 200 to 220 C. According to second version, sealing unit of stem is made either simultaneously with manufacture of single insertion part "shut-off member - stem" in form of circular projection of stem or simultaneously with manufacture of body with stem in form of circular projection on wall of hole of body for stem. EFFECT: enhanced efficiency of manufacture of cock; considerable reduction of number of parts to be assembled; low cost of manufacture. 8 cl, 9 dwg
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