GB1012571A - Improvements in or relating to safety devices for filters - Google Patents

Abstract

1,012,571. Oil filter safety device. G. MOATTI. Jan. 15, 1963 [Jan. 19, 1962; May 17, 1962], No. 1760/63. Heading B1D. A safety device operative upon the clogging of an oil filter has first and second elements subjected to the pressures obtaining at the inlet and at the outlet of the filter respectively, connecting means between said elements, spring means acting on the said connecting means so as to balance the differential pressure up to a predetermined safe value, and a contactor actuated by the above mentioned connecting means when the pressure difference across the filter exceeds said predetermined safe value due to an advanced clogging of the filter and thereby closing the circuit of the warning device whilst optionally effecting the opening of an electrically-controlled by-pass valve. In Fig. 1, the elements are the diaphragms 24 and 27. Duct 5 is connected to the inlet and duct 6 to the outlet of the filter, so that the inlet pressure is acting on diaphragm 24 and the outlet pressure on diaphgram 27. Spring 19 is adjusted by means of the thrust fixture 20, 21 and nut 22 so as to balance the normal inlet pressure and thus maintain rod 14 and heads 15, 16 and 17 in the position shown. As the filter becomes clogged, the pressure increases in chamber 2 and decreases in chamber 3 until the pressure in chamber 2 overcomes the action of the spring 19, so that the head 16, 17 is pushed to the left, as does head 15, drawn by rod 14, so that rod 30 moves away from the contactor 31 which closes, lighting lamp 32 and optionally effecting the opening of electrically-operated by-pass valve 34. In a variant, rod 30 is eliminated and the unit 20, 21 is hollow, enclosing a rod 35 (chain-dotted line). Contactor 31 is replaced by contactor 31<SP>1</SP> which is normally out of contact with the rod 35 but which is contacted as rod 14 moves to the left, so actuating the warning device. In Fig. 2, spring 19a rests against thrust collar 20a pierced by a central hole for a rod 14a connected to diaphragms 24a and 27a as in Fig. 1. The part situated between the diaphragms is hollowed-out to accommodate a contactor 31a actuated by a projection 36 or 36<SP>1</SP> carried by the rod 14a. In Figs. 3 and 4, levers 41, 41d are used to amplify the movement of the diaphragms 24c, 27c and 24d, 27d. In Figs. 2, 3 and 4, pistons fitted with rings or toroidal gaskets may replace the diaphragms. In Fig. 6, pistons 50, 54 having toroidal gaskets 49, 53 are used. If desired, the length of the body 1 or If may be reduced and the depth of the cups 8, 9 or 8, 9f increased, especially where toroidal gaskets are used, ducts 5 and 6 being arranged in the cups instead of in the body of the appliance. Specifications 833,395 and 904,983 are referred to.