Improvements in clarifiers

摘要

A unit for continuously removing contaminants from lubricating coolants comprises a vessel 1, Fig. 1, with a section 1a receiving the coolant and collecting relatively heavy particles of contaminant, the coolant flowing from this section to a flotation section 1b containing means for agitating and aerating the coolant to form a froth which is discharged together with lighter particles through an outlet 29, while the purified coolant passes to a receptacle 33. The froth is formed by a rotary motor-driven device 12 which aerates the liquid with air drawn through a casing 20. The froth is removed by a rotary skimmer 28. A byepass pipe 38, a control valve 36, and a check valve 39 are provided to maintain a substantially steady flow of liquid through the clarifier, part of the clarified liquid being re-circulated if the flow of incoming liquid falls below the desired rate. In a modification shown in Figs. 2 and 3, the clarifier comprises three sections 41, 42, 43. The coolant enters the section 41 from which settled solids are removed by rakes 47 on endless chains 48 and delivered to a portable tank 60. The coolant flows from the section 41 by way of a slot 59, a baffle 61 and an opening 62 into section 42 which is provided with a rotary froth-flotation device 65. The froth is removed by a skimmer 68 and the clear liquid flows through an opening 76 into the section 43 from which it is pumped through pipe 78. In a further modification three cylindrical members are arranged coaxially, the heavier solids being collected in the outer chamber, the froth in the inner chamber, and clarified liquid in the intermediate chamber. In the construction shown in Fig. 8 the froth is formed by a blower supplying compressed air through a distributor 155 provided with a canvas sheet 157. The distributor divides a casing 150 into two sections, the lower section collecting heavier solids 152 from coolant supplied through pipe 151, and the upper section containing the froth which is removed by a skimmer 158. Clear liquid flows through outlet 162. Means may be provided, as shown in Fig. 10, for removing automatically the solids in the settling chamber 200. The chamber has a conical base with an opening fitted with a plug 202 which is connected to a float 207. When sufficient solids accumulate in the chamber the float 206 rises and through lever mechanism withdraws the plug 202 from its seating allowing the solids to escape. Specification 615,705 is referred to.