Spray system pressure differential monitoring
A control method for a two-component spray system having first and second pumps for separate fluid components includes registering a target spray pressure, registering a material-specific pressure factor margin, sensing an output pressure of the second pump, and identifying a failure condition in the event that the sensed output pressure remains further than the pressure factor margin from the target spray pressure for at least a threshold time.
1. A spray system comprising:
a first fluid source configured to provide a first fluid comprising a first material;
a second fluid source configured to provide a second fluid comprising a second material;
a sprayer configured to combine and spray the first and second fluids;
a first pump configured to pump the first fluid at a variable first pumping speed from the first fluid source to the sprayer;
a second pump configured to pump the second fluid at a variable second pumping speed from the second fluid source to the sprayer;
a first pressure sensor disposed to sense a first output pressure of the first pump;
a second pressure sensor disposed to sense a second output pressure of the second pump; and
a controller configured to control the first and second pumps based on the first output pressure, and configured to a pump failure condition if the second output pressure differs from a target spray pressure by more than a material-specific pressure factor amount for more than a threshold duration, the threshold duration being a function of the first and second materials.
2. The spray system of claim 1 , wherein the controller is configured to control the first pump via a proportional-integral-derivative loop, and to control the second pump to follow the first pump at a target primary-to-secondary spray component flow ratio.
3. The spray system of claim 1 , wherein the first and second pumps are positive displacement reciprocating pumps.
4. The spray system of claim 1 , wherein the first fluid comprises a paint.
5. The spray system of claim 1 , wherein the second fluid comprises a catalyst.
6. The spray system of claim 1 , further comprising a local operator interface configured to accept inputs of the target spray pressure, the material-specific pressure factor margin, and the threshold duration from a user.
7. A control method for a two-component spray system having first and second pumps for separate first and second fluid components, the method comprising:
registering a target spray pressure;
registering a material-specific pressure factor margin;
sensing an output pressure of the second pump; and
identifying a failure condition if that the sensed output pressure differs from the target spray pressure more than the pressure factor margin for at least a threshold time
wherein the threshold time is a function of a first fluid material and a second fluid material.
8. The control method of claim 7 , wherein the target spray pressure is a target output pressure of the first pump.
9. The control method of claim 7 , wherein failure condition identification is disabled while the second pump is changing over.
10. The control method of claim 7 , wherein failure condition identification is disabled during a startup period of the second pump.
11. The control method of claim 7 , wherein the pressure factor margin is a function of the viscosity of at least the second fluid material.
12. The control method of claim 7 , further comprising logging user input.
13. The control method of claim 12 , wherein the user input includes the target spray pressure, the material-specific pressure factor margin, and the threshold time.
14. The control method of claim 7 , wherein identifying a failure condition comprises identifying at least one of an underpressure event and an overpressure event.