Positive displacement flushable flow meter
First Claim
1. A positive displacement flow meter for measuring the volume flow of liquid coating material delivered to spray coating apparatus and for being flushed clean of coating material by fluidic flushing media, said flow meter comprising a housing having inlet passage means and outlet passage means;
- means for supplying either liquid coating material at a first volume flow rate and under pressure or fluidic flushing media at a second and greater volume flow rate and under pressure to said inlet passage means;
movable liquid flow sensing means intermediate said inlet and outlet passage means for flow therethrough of coating material and flushing media from said inlet to said outlet passage means, said sensing means being moved in response to and at a rate in accordance with the volume flow rate of coating material or flushing media therethrough and generating an indication of the volumetric flow of coating material flowing therethrough;
bypass valve means for selectively shunting a portion of the fluid in said inlet passage means around said flow sensing means to said outlet passage means; and
means for operating said bypass valve means so that no fluid is shunted around said flow sensing means when coating material is supplied to said inlet passage means so that a portion of the fluid is shunted around said flow sensing means when flushing media is supplied to said inlet passage means.
4 Assignments
0 Petitions
Accused Products
Abstract
A positive displacement flushable flow meter has sensing elements that are rotated by and at a rate in accordance with a flow of fluid through the flow meter. The flow meter is particularly adapted for measuring the volume flow rate of coating material supplied to spray coating apparatus, and to permit the flow meter to be quickly flushed by means of alternate bursts of relatively high velocity air and solvent, without overdriving the sensing elements and damaging the flow meter, a bypass valve is provided. During a spray coating operation, the bypass valve is closed and all of the coating material flows past and rotates the sensing elements. During a flushing operation, the bypass valve is opened to divert some of the relatively high velocity flow of air and solvent around the sensing elements, while allowing a controlled and limited amount of air and solvent to move past and rotate the elements to clean them without causing them to be overdriven.
34 Citations
11 Claims
-
1. A positive displacement flow meter for measuring the volume flow of liquid coating material delivered to spray coating apparatus and for being flushed clean of coating material by fluidic flushing media, said flow meter comprising a housing having inlet passage means and outlet passage means;
- means for supplying either liquid coating material at a first volume flow rate and under pressure or fluidic flushing media at a second and greater volume flow rate and under pressure to said inlet passage means;
movable liquid flow sensing means intermediate said inlet and outlet passage means for flow therethrough of coating material and flushing media from said inlet to said outlet passage means, said sensing means being moved in response to and at a rate in accordance with the volume flow rate of coating material or flushing media therethrough and generating an indication of the volumetric flow of coating material flowing therethrough;
bypass valve means for selectively shunting a portion of the fluid in said inlet passage means around said flow sensing means to said outlet passage means; and
means for operating said bypass valve means so that no fluid is shunted around said flow sensing means when coating material is supplied to said inlet passage means so that a portion of the fluid is shunted around said flow sensing means when flushing media is supplied to said inlet passage means. - View Dependent Claims (2, 3, 4, 5, 6)
- means for supplying either liquid coating material at a first volume flow rate and under pressure or fluidic flushing media at a second and greater volume flow rate and under pressure to said inlet passage means;
-
7. A method of operating a positive displacement flow meter having at least one sensing element that is rotated in response to and at a rate in accordance with the volume flow rate of fluid through the flow meter, wherein the flow meter measures the volume flow of liquid coating material supplied under pressure to a spray coating apparatus, if flushed clean of coating material by fluidic flushing media, and the at least one sensing element has a maximum rate of rotation beyond which damage to the flow meter can occur, said method comprising the steps of supplying liquid coating material under pressure and at a first flow rate through the flow meter to the spray coating apparatus;
- detecting the revolutions through which the at least one sensing element is turned by the coating material to measure the volume flow of the coating material through the flow meter to the spray coating apparatus;
upon completion of supplying coating material, delivering fluidic flushing media under pressure and at a second and greater flow rate through the flow meter to clean the same of coating material; and
, during performance of said flushing media delivering step, shunting a portion of the flushing media around the at least one sensing element so that the at least one sensing element is exposed to only some of the flushing media which is sufficient to clean the at least one sensing element of coating material but is less than sufficient to rotate the at least one sensing element faster than its maximum rate of rotation. - View Dependent Claims (8, 9)
- detecting the revolutions through which the at least one sensing element is turned by the coating material to measure the volume flow of the coating material through the flow meter to the spray coating apparatus;
-
10. A positive displacement flow meter for measuring the volume flow of liquid coating material delivered to spray coating apparatus and for being flushed clean of coating material by fluidic flushing media, said flow meter comprising a housing having an inlet and an outlet;
- means for supplying either liquid coating material under pressure or fluidic flushing media under pressure to said inlet;
movable fluid flow sensing means in said housing intermediate said inlet and outlet for flow therethrough of coating material and flushing media from said inlet to said outlet, said sensing means being moved in response to and by an amount in accordance with the volume flow of coating material or flushing media therethrough and generating an indication of the volumetric flow of coating material flowing therethrough;
bypass valve means for selectively shunting a portion of the fluid from said inlet around said flow sensing means to said outlet; and
means for operating said bypass valve means so that no fluid is shunted around said flow sensing means when coating material is supplied to said inlet and so that a portion of the fluid is shunted around said flow sensing means when flushing media is supplied to said inlet.
- means for supplying either liquid coating material under pressure or fluidic flushing media under pressure to said inlet;
-
11. A method of supplying a measured volume of liquid coating material to spray coating apparatus, comprising the steps of supplying liquid coating material to the spray coating apparatus through a path including a movable fluid flow sensor that is moved in response to and by an amount in accordance with the volume flow of coating material therethrough;
- measuring the volume flow of coating material through the fluid flow sensor in accordance with the amount of movement thereof;
upon the measured volume flow of coating material reaching a selected value, interrupting said supplying step and delivering fluid flushing media through the path and the fluid flow sensor to clean the same; and
, during performance of said delivering step, shunting a portion of the flushing media in the path around the fluid flow sensor.
- measuring the volume flow of coating material through the fluid flow sensor in accordance with the amount of movement thereof;
Specification