GB592002A - Powder filling apparatus and method - Google Patents

Abstract

592,002. Packing granular material. GOLDEN STATE CO., Ltd. Oct. 11, 1944, No. 19623. Convention date, Sept. 20, 1943. [Class 94 (i)] An apparatus for filling containers 52 with powder such as dried milk is constructed with a chamber 10 provided with a movable support 68 for the container and fitted with a door 16 which can seal the chamber hermetically, the door being mounted on parallel arms 28, 29 on a shaft 26, which is geared by a sector 36 to pinions 33, 34, on trunnions 31, 32 on the door so that as the arms are swung to open the door, the door remains parallel to its closing position. The powder supplied by a tube 21 is introduced under control of a valve 22 which is opened automatically by the energization of an electromagnet 152, Fig. 7 (not shown), and closes automatically by energization of a magnet 111 controlled by a weighing device. The valve 22 is fitted with a mercury switch which controls the energization of a motor which drives a screw 41 which agitates the powder and assists its feed into the container. The support 68 can be raised and lowered by a piston 21 and this is in lowered position to receive a container when the door is fully opened. On closing the door an arm 122, Fig. 2, on shaft 26 rotates a wheel 118 by means of a pawl engaging a straight part 121 of an aperture 119, and wheel 118 drives a wheel 116 with a crankpin 114 and operates an arm 112 on a valve 96 which is thus connected to a vacuum device and this exhausts air from the container 10 as soon as the door closes. The exhausted air passes through an annular filter disc 59 and pipes 51a, 51b, 51c connected to a space 49 surrounding the filling nozzle and to the upper end of the chamber 10. The fall of pressure in the chamber 10 causes actuation of a diaphragm in a chamber 77 and consequent operation of a valve which causes reduction of pressure in cylinder 67 with raising of the platform 68 of the container so as to form a hermetic seal between the opening of the container and a sealing ring 56 secured to the top of the container. The continuous decrease of pressure in chamber 10 causes a pressure-responsive device 166, Fig. 4 (not shown), to close contacts so as to energize solenoid 152 which operates a lever arm connected by a link to an arm 145 on the valve 22. The chamber 10 and attached parts are supported by the movable platform 18 of a weighing device, and when the container is full, contacts are operated by the weighing-device to energize an electromagnet which closes the valve 22 to cut off the supply of powder and the valve 96 is operated to cut off the exhausting device and vent the chamber. The door 16 opens to a slight extent under action of a spring 143 which presses on the container. The opening movement of the container causes opening of a valve 129 connected to a source of an inert gas such as nitrogen to prevent action of oxygen on the packed powder. When the door 16 is opened fully the valve 76, Fig. 5 (not shown), is operated to vent the chamber 67 and permit the support 68 to be lowered for removal of the filled container. In a modification a pneumatic control is provided for gradually closing the valve 22 so that by the time the end of the powder-filling cycle is reached, the rate of powder flow has been considerably reduced, so that it is possible for the vacuum pump to reduce the pressure of the filling chamber to a lower value. It is stated that the process described acts to cool the powder so that in the case of powdered milk it can be packed soon after being formed