Viscosity Control System
A viscosity control system measures the thickness of the ink used in a printing press. This is very important for the quality of a print. The printing press needs a perfect density of the ink, otherwise the process is in danger of becoming worthless. The way to keep track of the density is with a viscosity control system. AV Flexologic offers the whole range that is needed for monitoring.
The ViscoCare system controls the viscosity of several colors with the use of one touchscreen. The system consists of a control cabinet (touchscreen and PLC), valves, pick-ups and the necessary cables for a constant viscosity. A maximum of 10 pick-ups both conventional and falling ball, can be linked to the system.
There are three different ViscoCare systems available:
- ViscoCare Standard One with a connection for one colour and a 4.3″ touchscreen
- ViscoCare Standard with connections for up to four colours and a 7″ touchscreen
- ViscoCare Central with connection for up to ten colours and a 12.1″ touchscreen
The touchscreen gives an image showing all information of the printing stations. The set value as well as the measured value of the viscosity can be checked by the operator. A diagram of the historice values for every colour can be recalled on the screen.
Viscosity Control System – Conventional Sensor
The conventional sensor has a brushless drive motor. The explosion-proof sensor placed in the liquid measures the rotational resistance. When the viscosity increases, then so does the liquid resistance, which will affect the speed of the revolutions of the rotating cylinder (pick-up device). When the viscosity goes beyond the limiting values (readable on the touch screen), the solenoid valve opens automatically and solvent/water will be added to the ink, until the pre-set viscosity is reached. Recently a very sensitive measuring device has been developed, providing even better measurement accuracy. The system is easy to clean and therefore simple to use.
Viscosity Control System – Self Cleaning Sensor
The ball sensor is controlled by an electromagnetic solvent/water valve. An explosion-proof sensor which is placed parallel to the ink tank (by-pass) into the pressure pipe determines the viscosity of the liquid (approximately twice per minute) by measuring the falling time of a ball. The falling time is determined by the resistance to the ink. When the viscosity increases, the falling time of the ball increases. The calculated viscosity interpreted by the system and solvent/water will automatically be added to the ink until the pre-set viscosity is reached. In rinsing mode, the liquid continuously flows through the sensor, thus removing any possible blockage in the ink supply.