Coating stretch tester

An apparatus for testing a coating fluid for runnability, the fluid having surface tension, viscosity, elasticity and dilatant behavior which influence the falling acceleration of the fluid under the influence of gravity, the apparatus comprising:

• a pressurized container adapted to receive the fluid, the container having an outlet;
• the outlet comprising a tube with an opening and means for regulating a flow rate of the fluid through the tube and out the opening for creating a continuous stream of fluid falling from the opening under the influence of gravity;
• air nozzle means for blowing a stream of gas at the continuous stream at each of two different heights for deflecting the continuous stream at each of the two different heights by an angle that is proportional to a velocity times flow rate or momentum of the continuous stream, at each respective height;
• and
• means for calculating the acceleration of the continuous stream as a function of the velocity of the continuous stream at the two different heights and the distance between the two different heights.

A method for measuring coating fluid runnability which is related to stretch and combined effects of surface tension, viscosity, elasticity and dilatant behavior of the fluid, the method comprising the steps of:

• loading a container with a quantity of the fluid;
• pressurizing the container;
• releasing the fluid from an outlet tube opening of the container to fall from the opening at a flow rate;
• regulating the flow rate so that the fluid forms into a continuous stream from the opening;
• and
• measuring a minimal flow rate at which the fluid leaves the opening in the continuous stream, the runnability and stretch being a function of the measured minimum flow rate.

A method for measuring the acceleration of a fluid, comprising:

• loading a container with a fluid;
• pressurizing the container;
• releasing a continuous stream of the fluid from an outlet of the container at a flow rate to form a continues stream of the fluid;
• horizontally deflecting the continuous stream of the fluid by blowing first and second air flows at the continuous stream, the first and second air flows being directed at two different heights along the continuous stream and deflecting the continuous stream at each height by a deflection angle proportional to the velocity times flow rate or momentum of the continuous stream at each height;
• and
• calculating the acceleration of the stream as a function of the velocity of the stream at the two different heights and the spacing between the two different heights.

An apparatus for testing a coating fluid for runnability, the fluid having surface tension, viscosity, elasticity and dilatant behavior which influence the falling acceleration of the fluid under the influence of gravity, the apparatus comprising:

• a pressurized container adapted to receive the fluid, the container having an outlet;
• the outlet comprising a tube with an opening and means for regulating a flow rate of the fluid through the tube and out the opening for creating a continuous stream of fluid falling from the opening under the influence of gravity;
• air nozzle means for blowing a stream of gas at the continuous stream at a known distance from the outlet, the stream of gas for deflecting the continuous stream at an angle that is proportional to a velocity times flow rate or momentum of the continuous stream;
• and
• means for calculating the acceleration of the continuous stream as a function of the velocity of the continuous stream.

A method for measuring the acceleration of a fluid, comprising:

• loading a container with a fluid;
• pressurizing the container;
• releasing a continuous stream of the fluid from an outlet of the container at a flow rate to form a continues stream of the fluid;
• horizontally deflecting the continuous stream of the fluid by blowing an air flow at the continuous stream at a known height and deflecting the continuous stream by a deflection angle proportional to the velocity times flow rate or momentum of the continuous stream at the known height;
• and
• calculating the acceleration of the stream as a function of the velocity of the stream.