Spray system pressure differential monitoring

Patent metadata

Field	Value
Publication number	US-2016153441-A1
Application number	US-201414905522-A
Country	US
Kind code	A1
Filing date	Jul 18, 2014
Priority date	Jul 19, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

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.

First claim

1 . A spray system comprising:
a first fluid source configured to provide a first fluid; a second fluid source configured to provide a second fluid; 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.

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 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.

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 threshold time is a function of the first and second materials.

12 . The control method of claim 7 , wherein the pressure factor margin is a function of the viscosity of at least the second fluid.

13 . The control method of claim 7 , further comprising logging user input.

14 . The control method of claim 13 , wherein the user input includes the target spray pressure, the material-specific pressure factor margin, and the threshold time.

15 . The control method of claim 7 , wherein identifying a failure condition comprises identifying at least one of an underpressure event and an overpressure event.

Assignees

• Graco Minnesota Inc

Inventors

• Fehr David L
• Ingebrand John R
• Van Keulen Dennis J

Classifications

• B05B15/55

  using cleaning fluids · CPC title

• F04B49/10 Primary

  Other safety measures · CPC title

• F04B15/02

  the fluids being viscous or non-homogeneous · CPC title

• B05B9/0406

  with several pumps · CPC title

• F04B19/22

  of reciprocating-piston type · CPC title