GB710870A - Improvements in or relating to sealing means for shafts or the like passing through an opening in a liquid-filled chamber - Google Patents

Abstract

710,870. Stuffing-box substitutes. FARNIER, A. April 19, 1951 [April 20, 1950; April 21, 1950; April 21, 1950], No. 9209/51. Classes 110(2) and 122(5) Leakage through an orifice of small cross sectional area in a liquid-filled chamber 1, such as the annular space 4 between an orifice 2 and a member 3 extending therethrough, is stated to be prevented when the liquid pressure rises by providing, between the inside and the outside of the chamber, a capillary passage 6 which exerts a surface tension resistance to flow lower than that existing in the orifice 4 but adequate to prevent the escape of liquid therethrough in normal circumstances, the length of the capillary passage 6 being sufficient to absorb the excess volume and pressure of the liquid. In a liquid meter the flow rate is measured by a rotor 41 which is housed in a chamber 33 and transmits its motion through a reduction gear and shaft 35 to a movement housed in a separate oil-filled chamber 34 communicating with the first chamber 33 through a spiral pipe 21 having a cross sectional area which is small but larger than that of the clearance 20 of the shaft 35 where it passes through the dividing wall of the chambers. Due to the capillarity of the pipe 21 and the shaft clearance 20 oil will not escape in normal circumstances from the chamber 34 and should the oil pressure be increased by any cause, such. as heating, it is relieved by oil flowing into the pipe 21 whose length is sufficient to absorb the excess volume. At low rates of flow in the supply pipe 37 the velocity of the liquid passing the rotor 41 is increased by passing through a restricting bore 10 in a spring-loaded valve 39 closing the pipe 37. When the rate of flow and consequently pressure increases in the supply pipe 37 to a predetermined amount the valve 39 opens and establishes free communication between the supply pipe and the rotor chamber. The rotor shaft 13 is coned at its ends and runs in sapphire bearings.