Flow control sensor and method for filling of a filter press
AssigneeUnited States Filter Corporation
InventorDavid M. Higgins
Life of this patent
Estimating the term…
Abstract
An air flow sensor and method for filling a filter press which detects slowing and/or intermittent stoppage of the feed pump and signals a controller associated with a pressure regulator to increase the pressure of the air supplied to the feed pump. The air flow sensor includes a spring-biased piston slidably movable within a housing, which piston defines a flow passage therein and carries a magnet thereon. A switching device is mounted on the housing and detects the position of the piston magnet, and when the piston approaches the closed position, the switching device transmits a signal to step-up the air pressure to the feed pump.
Claims22
A filter press comprising:
- a horizontally elongate frame;
- first and second head assemblies mounted at opposite ends of said frame, said first head assembly being disposed adjacent one end of said frame and supported for horizontal movement toward and away from said second head assembly so as to be respectively movable into closed and opened positions;
- a plurality of filter plates supported on said frame for movement therealong between said first and second head assemblies, said filter plates being pushed together into a horizontally extending closed stack and clampingly held between said first and second head assemblies when said first head assembly is moved toward said second head assembly into said closed position;
- a feed pump for supplying slurry material under pressure to said plurality of filter plates, said feed pump being connected to a source of air by an air supply line;
- a pressure regulator associated with said air supply line for maintaining the air supplied to said feed pump at a predetermined pressure;
- and
- an air flow sensor mounted in said air supply line between said feed pump and said pressure regulator, said air flow sensor having an upstream end and a downstream end and including a housing defining a chamber therein, and a piston slidably disposed within said chamber and movable between a first position which permits air flow from said air supply line through said sensor in response to upstream air pressure and a second position which restricts air flow through said sensor in response to downstream air pressure generated during a press filling cycle which is indicative of slowing of said feed pump, said sensor being adapted to transmit a signal to a controller associated with said pressure regulator upon said piston moving into said second position to increase the pressure of the air supplied to said feed pump.
An air flow sensor for mounting in one of an air supply line for supplying air to a feed pump of a filter press and an exhaust line associated with the feed pump, said sensor comprising:
- an elongate and generally tubular housing defining a longitudinal axis and having an inner wall defining an interior chamber extending generally along the axis;
- a piston slidably disposed within said chamber and defining an axially extending bore therein, said piston being axially movable within said chamber between an open position for permitting air flow through said bore and a closed position for substantially closing off said bore to air flow, said piston having a magnet mounted thereon for movement therewith;
- and
- a switching device mounted on said housing for detecting an axial position of said magnet as said piston approaches said closed position upon slowing of a feed pump during a press filling cycle, said switching device transmitting a signal to a controller to increase the pressure of the air supplied to the feed pump and being adjustable to accommodate air flow through said sensor proportional to the capacity of said feed pump.
A method for filling a filter press having a feed pump for supplying slurry material under pressure to a plurality of filter plates, a pressure regulator associated with an air supply line connected to the feed pump, and a controller for operating the pressure regulator, said method comprising:
- (1) providing an air flow sensor in the air supply line between the feed pump and the pressure regulator, the air flow sensor having a piston including a flow passage therethrough and being movable between open and closed positions;
- (2) adjusting the air flow sensor to sense a closing movement of the piston and thus a decrease in air flow volume through the air flow sensor proportional to the feed pump capacity;
- (3) supplying pressurized air to the feed pump through the air flow sensor by moving the piston thereof into the open position and feeding slurry into the filter press;
- (4) performing said step (3) until the slurry pressure in the filter press approaches the supply pressure and causes the piston of the air flow sensor to move from the open position toward the closed position;
- (5) sensing the position of the piston as same approaches the closed position, and before the piston fully closes transmitting a signal to the controller to increase the supply pressure to the feed pump;
- and
- (6) repeating said steps (3) through (5) at the increased supply pressure until a predetermined maximum supply pressure is reached.
A method for filling a filter press having a feed pump for supplying slurry material under pressure to a plurality of filter plates, a pressure regulator associated with an air supply line connected to the feed pump, a controller for operating the pressure regulator, and an exhaust line connected to the feed pump, said method comprising the steps of:
- (1) providing an air flow sensor in the exhaust line, the air flow sensor having a piston including a flow passage therethrough, said piston being movable between open and closed positions and being normally biased into said closed position;
- (2) adjusting the air flow sensor to sense a closing movement of the piston and thus a decrease in air flow volume through the air flow sensor proportional to the feed pump capacity;
- (3) supplying pressurized air to the feed pump through the air supply line and feeding slurry into the filter press;
- (4) supplying a pressurized air pulse generated by the feed pump to the exhaust line to move the piston of the air flow sensor into the open position, and thereafter returning said piston to said closed position;
- (5) repeating said steps (3) and (4) until the piston remains in the closed position for a period of time greater than a predetermined time period and thereafter transmitting a signal to the controller to increase the supply pressure to the feed pump.
Dependencies are inferred from the claim text.