HYDROVAC

DUST HANDLING APPARATUS INCLUDING DUST COLLECTING HOPPERS, VALVES TO REMOVE DUST FROM SUCH HOPPERS, PIPING THROUGH WHICH SUCH DUST MAY BE CONVEYED AND MEANS FOR CREATING VACUUM OR SUBATMOSPHERIC PRESSURE IN SAID PIPING AND VALVES, SUCH APPARATUS BEING USED PARTICULARLY IN CONNECTION WITH COAL BURNING FURNACES