GB1270971A - Method and apparatus for filtering or sifting out fine particles by utilizing supersonic vibration - Google Patents

Abstract

1,270,971. Wet screening. NIPPON STEEL CORP. 14 April, 1969 [15 April, 1968; 26 April, 1968; 5 Aug., 1968; 27 Sept., 1968; 3 Oct., 1968; 27 Nov., 1968; 30 Dec., 1968], No. 18997/69. Headings B1D and B2H. [Also in Division C7] Particles in suspension in a liquid are filtered out or graded according to size by introducing the suspension into a container in which one or more sieves are arranged and imparting supersonic vibrations to the suspension and to the sieve or sieves. In Figure 1, a suspension 10 of fine particles is contained in a container 2 in which are mounted a series of superposed sieves 3, 4, 5 with apertures decreasing in size progressively downwards. A supersonic oscillator 1 is adjustably positioned in the container and is connected by a line 6 to a supersonic wave generator (not shown). A vibration transmitter 7 is set at the tip of the oscillator 1. A funnel 8 below the screen 5 is connected to a suction pump (not shown) via a pipe 9. In operation, liquid is introduced into the container 2 and the vibration transmitter 7 is moved close to the sieve 3 and the oscillator 1 is energized. A liquid suspension of particles to be graded is then introduced into the container and if. necessary, suction is applied to the pipe 9. The vibrations serve to break up any agglomerated particles thereby preventing choking of the sieves. The sieves 3, 4, 5 are successively removed with the particles retained thereon, the vibration transmitter being successively moved down close to the sieves 4 and 5 after removal of the sieves 3 and 4 respectively. In Figure 2, an apparatus for determining the size distribution of particles of a powder includes a sieve unit 12 comprising a number of sieves placed one above the other and spaced apart from one another and clamped between a container 13 and a funnel 8 which is mounted on a collecting flask 16 provided with a suction pipe 9. Each sieve element may be constructed by immersing a metal or organic film provided with a number of holes in a treatment bath and subjecting it to chemical plating and/or electroplating whilst supersonic vibration is applied so as to contract the size of the holes uniformly by the metal layer deposited thereon and to increase the strength of the sieve element. The sieve element may be attached at its peripheral portion to a synthetic resin or rubber ring to constitute a sieve. Alternatively, the sieve is formed by fitting a sieve element F, Figure 6, in a groove 27 in the inside surface of a synthetic resin holder P which is provided with a socket 25 and a spigot 26. When a number of such sieves are mounted in the apparatus to form the sieve unit A the spigot 26 of one holder is received in the socket of a lower holder.