Demister Apparatus and Method

Abstract

A demister apparatus for machine tools having an enclosure booth for confining mist in which a varying outflow of air is drawn from the booth and directed to a remote demister apparatus from a minimum when the access doors to the enclosure are closed to a maximum when one or more of the doors are opened. The air flow may also be varied with the number of machine tools in operation as well with the state of filters in the remote demister apparatus. A cyclonic separator is also provided adjacent to the booth which functions well in a vertical up flow mode over a range of air outflow rates of flow.

1 . A demister apparatus for eliminating mist generated in a machining center having an enclosure booth with one or more access door panels which are opened for loading and unloading parts to be machined therein but closed during a cycle of machining of said parts, comprising:
 an electric motor driven blower arranged to continuously draw a flow of air out of said booth to maintain a partial vacuum in said booth sufficient to prevent the escape of air containing mist from within said booth;   an exhaust duct system connected to said blower so as to receive said air flow drawn out of said booth;   a demister apparatus remote from said booth including one or more filters connected to said exhaust duct system and including said blower which when operated drawing an air flow out of said booth, said drawn out air flow passing through said one or more filters in said remote demister apparatus and thereafter exhausted through an outlet;   a cyclonic demister installed in said exhaust duct system at a location adjacent said machine tool station booth, said air flow drawn out of said booth passed through said cyclonic demister to remove a substantial portion of mist contained therein prior to reaching said remote demister apparatus; and   an arrangement increasing the power to said drive blower motor to thereby increase the air flow drawn out of said booth when an increase in air pressure in said booth occurs or is imminent which increase air pressure would otherwise reduce the vacuum level in said booth, said increased in power counteracting the reduced thereof, said arrangement including a VFD controller associated with said blower drive motor, said VFD controller increasing said blower drive motor power in order to increase the air flow drawn out of said booth when air pressure in said booth occurs or is imminent.   
     
     
         2 . The apparatus according to  claim 1  wherein said arrangement includes a machine control generating a corresponding signal or signals when one or more of said access panel doors are about to begin to be opened, said signals transmitted to said VFD controller so as to cause said increase in blower drive motor power to produce said increase in said rate of air flow drawn from said booth. 
     
     
         3 . The apparatus according to  claim 1  wherein said machining center includes a plurality of machine tools and wherein said VFD controller reduces the power to said motor driven blower when fewer than all of said machine tools are in operation. 
     
     
         4 . The apparatus according to  claim 1  wherein a sensor is included detecting the level of blockage in one or more of said filters and wherein said VFD controller increases power to said blower drive motor in response to signals from said sensor corresponding to a predetermined degree of blockage of said one or more filters. 
     
     
         5 . The apparatus according to  claim 1  wherein said cyclonic separator comprises:
 a vertical cylindrical tube provided with an inlet and an exit opening to allow air to be drawn therethrough in an up direction; 
 a set of stationary vanes connected in each of the upstream and downstream portions of the tube and sized and positioned to direct the air flowing therethrough in a cyclonic path through the tube such that mist in the air therein migrates outwardly to and in the downstream direction along the inside wall of the tube; 
 a drain hole positioned near the upstream end of the collection chamber. 
 
     
     
         6 . The apparatus according to  claim 1  wherein said arrangement includes a sensor detecting an increase in said air flow drawn from said booth and generating a corresponding signal transmitted to said VFD controller which increases said power to said blower drive motor correspond. 
     
     
         7 . The apparatus according to  claim 1  further including a vacuum sensor associated with said booth generating a corresponding signal transmitted to said VFD controller to increase or decrease the power to said blower drive motor so as to substantially maintain a predetermined vacuum level therein sufficient to substantially prevent the escape of booth air during a machining cycle. 
     
     
         8 . The apparatus according to  claim 1  further including a switch arranged to detect opening movement of an access door panel and generate a corresponding output signal which is transmitted to said VFD controller to cause an increase in said blower drive motor power to increase the rate of air flow drawn from said booth upon opening of an access door panel. 
     
     
         9 . A method for eliminating mist generated in a machine tool installation having a booth with one or more access door panels which are opened for loading and unloading parts therein but closed during a cycle of machining of said parts comprising:
 a blower connected to said booth and operated with a drive motor so as to continuously draw a flow of air out of said booth to maintain a partial vacuum in said booth sufficient to prevent the egress of air containing mist from said booth other than said air flow drawn out of said booth;   connecting an exhaust duct system to receive said air flow drawn out of said booth;   providing a remote demister apparatus including one or more filters connected to said exhaust duct system receiving said air flow out of said booth and passing said air flow through said one or more filters in said remote demister apparatus and thereafter exhausting said air flow through an outlet;   installing a cyclonic demister in said exhaust duct system at a point adjacent said machine tool station booth, said air flow drawn out of said booth passed through said cyclonic demister to remove a substantial portion of mist contained therein prior to entering said remote demister apparatus; and   increasing the power to said blower drive motor when an increase in air pressure in said booth occurs or is imminent which would otherwise reduce the vacuum level therein to counteract the effects thereof.   
     
     
         10 . The method according to  claim 9  including generating a corresponding signal when one or more of said access panel doors are about to begin to be opened, and transmitting signals to a VFD controller associated with said blower drive motor to cause a corresponding increase in blower drive motor power to in turn increase the rate of air flow drawn from said booth. 
     
     
         11 . The method according to  claim 9  wherein said machine tool installation includes a plurality of machine tools and wherein said VFD controller is operated to reduce the power to said blower drive motor whenever fewer than all of said machine tools are in operation. 
     
     
         12 . The method according to  claim 9  wherein a sensor is included detecting the level of blockage in one or more of said filters and increasing the power to said blower drive motor in response to signals from said sensors corresponding to a predetermined degree of blockage of said one or more filters. 
     
     
         13 . The method according to  claim 9  wherein said cyclonic separator comprises:
 a vertical cylindrical tube provided with an inlet and exit opening to allow air to be drawn therethrough in an up direction; 
 connecting a set of stationary vanes in each of the upstream and downstream portions of the tube and sized and positioned to direct the air flowing therethrough in a cyclonic path through the tube such that mist in the air therein migrates outwardly to and in the downstream direction along the inside wall of the tube; 
 positioning a drain hole near the downstream end of the collection chamber. 
 
     
     
         14 . The method according to  claim 9  including sensing an increase in said air flow from said booth and transmitting a corresponding signal to a VFD controller connected to cause an increase in power to said blower drive motor. 
     
     
         15 . The method according to  claim 9  including sensing the vacuum within said booth and generating a corresponding signal and transmitting the same to a VFD controller to increase or decrease the power to said blower drive motor so as to substantially maintain a predetermined vacuum level therein sufficient to substantially prevent the escape of air in said booth. 
     
     
         16 . The method according to  claim 9  further including detecting opening movement of an access door panel and generating a corresponding output signal and transmitting the same to a VFD controller so as to cause an increase in blower drive motor power to increase the rate of air flow drawn from said booth upon opening of an access door panel. 
     
     
         17 . A demister apparatus for eliminating mist generated in a machine tool installation having a booth with one or more access door panels which are opened for loading and unloading parts therein but closed during a cycle of machining of said parts, comprising:
 a blower having a drive motor continuously drawing a flow of air out of said booth to maintain a partial vacuum in said booth sufficient to prevent the escape of air containing mist from said booth;   an exhaust duct system connected to receive said air flow drawn out of said booth;   a remote demister apparatus including one or more filters connected to said exhaust duct system and including said blower when operated drawing an air flow out of said booth, said drawn out air flow passing through said one or more filters in said remote demister apparatus and thereafter exhausted through an outlet; and   an arrangement increasing the power to said drive blower motor when an increase in air pressure in said booth occurs or is imminent which would otherwise reduce the vacuum level therein to counteract the effects thereof, said arrangement including a VFD controller associated with said drive motor, said VFD controller increasing said drive motor power in order to increase the air flow drawn out of said booth.   
     
     
         18 . A method for eliminating mist generated in a machine tool installation having a booth with one or more access door panels which are opened for loading and unloading parts therein but closed during a cycle of machining of said parts comprising:
 a blower connected to said booth and operated with a drive motor so as to continuously draw a flow of air out of said booth to maintain a partial vacuum in said booth sufficient to prevent the escape of air containing mist from said booth;   connecting an exhaust duct system to receive said air flow drawn out of said booth;   providing a remote demister apparatus including one or more filters connected to said exhaust duct system receiving said air flow out of said booth and passing said air flow through said one or more filters in said remote demister apparatus and thereafter exhausting said air flow through an outlet; and   increasing the power to said blower motor when an increase in air pressure in said booth occurs or is imminent which would otherwise reduce the vacuum level therein to counteract the effects thereof including installing a VFD controller associated with said drive motor so as to increase said drive motor power.