Liquid Dosing Control Manual
9.17.150 rev A – September 2020
Page
17
of
34
3. Prepare for operation
The main purpose of this section is to prepare the Bronkhorst Liquid Dosing Set for operation.
This includes filling the controlling instrument and actuator with liquid, flushing all the air from the
dosing set, and performing an instrument Auto-Zero function.
Tip !
The goal is to completely fill the instrument and actuator with liquid. This is required for a smooth
start of the control loop, and for this reason it is not necesseray to completely fill the downstream
process lines at this time.
By opening a drain point (if installed) directly downstream of the dosing set, the filling time can be
reduced and the presence of liquid can be directly observed.
Only if the fluid, method of collecting the drained liquid and process environment allows for this
tip.
3.1 Fill the system
Filling the system is the first step of removing all air to ensure a stable and smooth control loop.
1. Prepare the system to be filled
- Make sure all fluid connections have been leak tested
- Make sure the system outlet is connected to the process or a suitable waste
- Open (if applicable) process valves outside the Bronkhorst set
To ease the filling process by decreasing the system pressure drop and volume to be filled
- Open (if present) a drain point between the Bronkhorst set and the process
- Close (if present) the installed bypass downstream of the pump
Note, ensure that any liquid is safely collected at the opening.
Ensure Batch Mode is disabled
- Write value 0 to parameter 130 – Counter Mode
(Batch Mode disabled)
2. Slowly operate the actuator to draw in liquid
- Write value <___> to parameter 206 – Flow setpoint
(provide setpoint to draw liquid)
Choose 10% of the normal operation flow of the system as setpoint at this step. Increase
with steps of 10% to speed up the filling process.
Filling a system can take a long time depending on tube diameters and the configured
flow rate of the system. By taking larger setpoint steps, the filling time can be reduced,
but when the system is sensitive to pressure spikes, then take caution and use a slow but
steady flowrate.
