GB1093785A - Improvements in or relating to apparatus for the treatment of castings - Google Patents

Abstract

1,093,785. Treating castings. TILGHMAN'S WHEELABRATOR Ltd. Aug. 12, 1966 [Aug. 27, 1965], No. 36852/65. Heading B3D. Apparatus for the treatment of castings comprises blasting means for directing particulate abrasive magnetizable material at the castings, conveying means for intermittantly conveying the castings past said blasting means, magnetic separating means for separating the used abrasive material from non- magnetizable contaminants, and feed means for automatically feeding abrasive free from contaminants to the blasting means. Apparatus for the decoring and removal of heavy surface debris from castings comprises a blasting machine 1 having an impeller wheel 2, conveying means such as a tumbling barrel, a swing table, car table or hanger type in which castings are hung from an overhead rail, and separating means for particulate steel abrasive. The separating means comprises a bucket elevator 3, a rotary sieve 4, a magnetic separator 5 and a pneumatic separator 6. The magnetic separator 5 consists of a rotary magnetic drum 7, a storage hopper 8 having a control valve 9, and a swing plate 10. While the castings are being loaded into the machine and for a period of time afterwards, the tumbling barrel is rotated to agitate the castings which results in a high proportion of the sand from the casting being removed before blasting starts. Sand falls on to a perforated floor plate, which may be stationary or vibrating, and passes along the line A to be sieved and discharged past swing plate 10, which is open, along the line B. When blasting is started, valve 9 and swing plate 10 are closed. Spent particulate steel abrasives together with contaminants including core sand, gits, wire and flash passes to the rotary sieve 4 where the gits, wire and flash are removed, the remainder falling into the magnetic separator 5. The magnetic portion, consisting primarily of steel abrasive, follows the line D past a demagnetiser and up the elevator 3 to the pneumatic separator 6 which removes residual non-magnetic contaminants and abrasive which has become too small to use, the cleaned abrasive being then ready for re-use by the wheel 2. The non-magnetic portion, consisting primarily of sand follows the line C and is stored in the hopper 8. When blasting is stopped, the valve 9 is opened and the non-magnetic portion is recirculated for a second pass separation into sand, discharged along the line B, and re-usable abrasive which is passed into the pneumatic separator 6. Instead of a rotating magnetic drum the magnetic separator may be of overband type of other single or multipole embodying permanent or electro-magnets.