GB1234022A - - Google Patents

Abstract

1,234,022. Centrifugal separators. PLOUGH (CONTRACTS) Ltd. and D. V. GOUGH. 30 July, 1968 [2 May, 1967], No. 20345/67. Headings B1D and B2P. [Also in Division F2] An apparatus for separating constituents of a mixture of liquids or liquid and solids of different densities comprises a casing 56, 58, 62, Fig. 1, divided into lower and upper chambers 50, 52 by a partition 54 which is provided with an opening controlled by a valve 92 which is adapted to be closed, upon accumulation of a denser constituent in the lower chamber, by a float 118 located in the lower chamber. The lower chamber is divided into upper and lower regions communicating through a conduit 74 extending downwardly into the lower region and having its lower end spaced from the bottom of the lower chamber and occupying a substantial part of the cross-sectional area of the lower chamber at the same level. An inlet for the mixture (not shown, see Fig. 1) is located in an upper end of the lower chamber 50 above the lower end of the conduit 74 so that the flow through the lower chamber is directed downwardly between the conduit and the chamber wall and is then drawn upwardly through the conduit to the valve-controlled opening. This permits a dense constituent of the mixture to settle in the bottom region of the lower chamber below the conduit 74 and a light constituent to enter the upper chamber 52 from which it is discharged through an outlet 120. The apparatus may be used for dewatering the fuel of a diesel powered vehicle. The inlet for the mixture is through the wall of the cylindrical region of the upper portion 58 of the chamber 50 and is laterally offset with respect to the central axis of the chamber so as to initiate a swirling motion in the downward flow of the mixture to promote separation of its constituents by centrifugal force. Alternatively or, as shown, additionally, guide vanes 76 are fixed to the conduit or to the wall of the lower chamber to cause or assist the swirling motion. A heater 86 and a drain tap 88 are provided in the lower end of the chamber 50. Communication between the chambers 50, 52 is by means of holes 94 formed in the partition 54 at the bottom of a recess which may be closed or opened by means of the valve 92 which is connected to the float 118, the latter rising with the level of the separated water and causing the valve to close the recess when this level has reached a predetermined point. As the float rises it also causes a poppet valve 142 to be displaced from its seating 128 by the stem of valve 92. When the valve 92 has closed, a pressure drop occurs in the chamber 52 due to continued withdrawal of the fuel through the outlet 120 by means of the diesel engine fuel pump. This fall in pressure draws the valve 92 against its seat and is transmitted to the lower side of a spring-biased diaphragm 122 which causes the movable member 136 of a switch 134 to move down and close an electrical circuit and actuate a visual and/or audible warning device 141 which may be located in the vehicle cab, whereupon the driver draws off the accumulated water by holding open the drain tap 88 until fuel flows from the tap. To re-open the valve 92, which is kept closed by the suction created in the chamber 52, there is provided a bleed passage by-passing the valve 92 and comprising bores 98, 100, Fig. 4, formed in the partition 54, the bore 100 being normally closed by a spring-biased valve 102 which is retracted by a knob 110 to open the bore 100 to allow fuel to be drawn in the upper chamber 52 through the bleed passage and thus equalise the pressures on either side of the valve 92 which will then fall from its seat. A baffle plate 78, Fig. 3, prevents the clean fuel discharging from the upper end of the conduit 74 from impinging directly on the bottom face of the valve 92 to avoid its premature closure. The apparatus may also be used to separate grit from diesel fuel or oil.