PISTON COMBINATION SEAL Russian patent published in 2001 - IPC

FIELD: mechanical engineering. SUBSTANCE: proposed combination seal is designed for sealing piston in plants handling liquids containing mechanical impurities, such as sand, slime, mud, etc. Seal is placed between piston and cylinder housing and it contains two flexible rings of rectangular shape made, for instance, from rubber and fitted on surface of piston body with antifriction coating which does not stick to flexible ring material. Rings are separated by support bushing made of antifriction metal and fitted on piston body for displacement along axis and resting against cylinder. Low-friction rings are fitted on flexible rings. These rings are in contact with cylinder and are made of strip of antifriction wear-resistant flexible fluoropolymer compositions in form of several sectors interconnected by locks of type "rectangular tennon - strip lengthwise slot". Width of low-friction ring is less than width of flexible ring. Pack of flexible ring, support bushing are compressed with light interference along axis on piston body between its flange and pressure nut. Flange, support bushing and pressure nut limit mobility of low-friction rings along axis within the limits of width difference of flexible and low-friction rings. EFFECT: improved reliability of seal. 5 dwg