초록 ▼

Apparatus is disclosed for continuously filtering a flow of melted plastic which includes a mechanism for purging the filter without interrupting continuous operation. A filter screen is disposed in a circular chamber within the filter housing. A collector plate including a plurality of radially ori

Apparatus is disclosed for continuously filtering a flow of melted plastic which includes a mechanism for purging the filter without interrupting continuous operation. A filter screen is disposed in a circular chamber within the filter housing. A collector plate including a plurality of radially oriented, triangularly shaped passages is disposed on the upstream side of the filter screen, defining triangular pockets for collecting contaminants that cannot pass through the filter screen. A collector head is rotatably disposed for selective registration with the collector pockets, and an indexing mechanism is included for sequentially stepping the collector head around the collector plate for momentary registration with each collector pocket. The collector head communicates with a contaminant discharge passage that is opened and closed in timed sequence with movement of the collector head. With the collector head in position over a triangular pocket and the contaminant discharge passage open, a part of the filtered plastic downstream of the filter screen reverses its flow through the screen and collector head, purging the screen by carrying collected contaminants with it. The discharge passage is opened for a short period of time so that the reverse flow for each pocket is a small discrete volume. Because of this, the combined discrete quantities of filtered plastic used in the screen purging process as the collector head cycles through communication with each pocket is held to a minimum, while at the same time insuring continuous filtering operation.

대표청구항 ▼

Apparatus for continuously filtering a flow of material, comprising: housing means defining an inlet for the unfiltered material and an outlet for filtered material; filter means disposed in the housing between the inlet and outlet; collector means disposed adjacent the filter means on its upstream

Apparatus for continuously filtering a flow of material, comprising: housing means defining an inlet for the unfiltered material and an outlet for filtered material; filter means disposed in the housing between the inlet and outlet; collector means disposed adjacent the filter means on its upstream side, the collector means having a plurality of separate passages defining collector pockets for contaiminants filtered by the filter means, the collector means being otherwise imperforate; collector head means disposed in the housing means for movement relative to the collector means, the collector head means being configured for discrete communication with each of said collector pockets; first drive means for moving the collector head means through a series of stationary positions in stepped sequence, each stationary position corresponding to a collector pocket with which the collector head means is in registration; a contaminant dischage passage disposed in the housing means in communication with the collector head means, the discharge passage including a discharge outlet for contaminants; valve means for blocking the discharge passage between the collector head means and discharge outlet in a first position, and for opening the discharge passage in a second position; second drive means for moving the valve means between said first and second positions; and actuator means commonly connected to the first and second drive means for simultaneous operation thereof in timed relation, the actuator means and first and second drive means being contructed and arranged to open the discharge passage when the collector head means is in stationary registration with a selected collector pocket, and to close the discharge passage when the collector head means is moved between collector pocket registration positions.