On-demand high volume, low pressure spray system

Patent metadata

Field	Value
Publication number	US-10328442-B2
Application number	US-201715437019-A
Country	US
Kind code	B2
Filing date	Feb 20, 2017
Priority date	Feb 21, 2016
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

Various embodiments concern a sprayer having a blower that outputs a HVLP flow of air into a hose, the hose connecting with a spray gun. A pressure sensor measures pressure of the HVLP air within the hose via a tube that branches from a fitting to which the hose connects. If the sensor indicates that the pressure level has increased above a threshold amount, indicating that the trigger of the spray gun is not being actuated, then power output to the blower is reduced (e.g., stopped). HVLP air is trapped within the hose by two valves when the trigger is not actuated. When the sensor indicates that the pressure level has decreased, corresponding to release of the trapped HVLP air into the gun for spraying by actuation of the trigger, power to the blower is increased (e.g., resumed).

First claim

The following is claimed:

1. A sprayer comprising:
an air supply unit comprising an motor, the air supply unit configured to output a flow of pressurized air by operation of the motor;
a hose having a first end and a second end, the first end receiving the pressurized air output by the air supply unit;
a spray gun having a trigger and a first valve, the second end of the hose connected to the spray gun, wherein actuation of the trigger causes the first valve to open and the spray gun to spray fluid using the pressurized air from the hose;
a second valve located upstream of the hose and through which at least a portion of the pressurized air output by the air supply unit flows;
a sensor that outputs a signal indicative of whether the trigger is actuated; and
control circuitry that receives the signal and regulates power output to the motor, the control circuitry configured to reduce electrical power output to stop the motor such that the air supply unit stops outputting the flow of pressurized air based on the signal indicating that the trigger is not actuated, and increase electrical power output to restart the motor such that the air supply unit resumes outputting the flow of pressurized air based on the signal indicating that the trigger is actuated,
wherein a volume of the pressurized air is trapped within the hose by the first and second valves when the first and second valves are closed, and the volume of the pressurized air is used by the spray gun for spraying while the trigger is actuated yet the motor is accelerating.

2. The sprayer of claim 1 , wherein the sensor is a pressure sensor.

3. The sprayer of claim 2 , wherein the signal is indicative of the pressure of the pressurized air when the pressurized air is either trapped or flowing between the first and second valves.

4. The sprayer of claim 3 , wherein the control circuitry is configured to reduce electrical power output to the motor based on the signal indicating that the trigger is not actuated by indicating that the pressure of the pressurized air has increased.

5. The sprayer of claim 4 , wherein the control circuitry is configured to increase electrical power output to the motor based on the signal indicating that the trigger is actuated by indicating that the pressure of the pressurized air has decreased.

6. The sprayer of claim 2 , wherein the sensor is exposed to pressurized air via a tube that branches from a pneumatic circuit between the first and second valves.

7. The sprayer of claim 1 , wherein the second valve is located within a fitting to which the hose attaches.

8. The sprayer of claim 1 , wherein the second valve is a check valve.

9. The sprayer of claim 1 , wherein the first valve is located within a body of the spray gun.

10. The sprayer of claim 1 , wherein the air supply unit comprises a blower.

11. The sprayer of claim 1 , wherein, in reaction to actuation of the trigger, the volume of the pressurized air that was trapped in the hose is released into the spray gun and used for spraying fluid while the control circuitry increases electrical power output to the motor to accelerate the motor to resupply pressurized air to the hose.

12. The sprayer of claim 1 , wherein the control circuitry is configured to reduce electrical power output to the motor based on the signal indicating that the trigger is not actuated by: starting a timer for a predetermined amount of time and then reducing electrical power output to the motor if the signal indicates that the trigger was not actuated during the counting of the timer, but not reducing electrical power output to the motor if the signal indicates that the trigger was actuated during the counting of the timer.

13. The sprayer of claim 1 , wherein the air supply unit comprises a fan, an impeller, or a turbine that is rotated by the motor to generate the flow of pressurized air.

14. The sprayer of claim 1 , further comprising a fluid reservoir attached to the spray gun from which the spray gun draws fluid for spraying.

15. A sprayer comprising:
a blower configured to output a flow of pressurized air by operation of a motor;
a hose;
a spray gun having a trigger and a first valve, the spray gun receiving the flow of pressurized air from the blower through the hose, wherein actuation of the trigger causes the first valve to open and the spray gun to spray fluid;
a second valve, the second valve being a check valve, wherein the flow of pressurized air flows through each of the first and second valves when the first and second valves are in open states, and the second valve is configured to close based on closure of the first valve;
a pressure sensor that measures the pressure of the pressurized air within the hose between the first and the second valves and the measured pressure; and
control circuitry that receives the signal, the control circuitry configured to reduce power output to the motor of the blower based on the signal indicating an increase in air pressure within the hose between the first and second valves due to the first and second valves being closed and increase power output to the blower based on the signal indicating a decrease in air pressure within the hose between the first and second valves due to the first valve being opened while the second valve remains closed,
wherein a volume of the pressurized air is trapped within the hose between and by the first and second valves when the first and second valves are closed due to the trigger not being actuated, and in reaction to actuation of the trigger, the first valve is opened such that the volume of trapped pressurized air is released in the spray gun and used for spraying fluid while the second valve remains closed and the control circuitry increases power output to the blower to accelerate the blower to resupply the flow of pressurized air to reopen the second valve and flow through the hose to the spray gun to spray fluid.

16. The sprayer of claim 15 , wherein the control circuitry is configured to reduce the power output to the motor based on the signal indicating that the pressure has increased such that the blower stops outputting the flow of pressurized air, and the control circuitry is configured to increase the power output to the motor based on the signal indicating that the air pressure has decreased such that the blower resumes the flow of pressurized air.

17. The sprayer of claim 15 , wherein the pressure sensor measures the pressurized air within the hose between the first and second valves via a tube that branches from a pneumatic circuit between the first and second valves.

18. The sprayer of claim 15 , wherein the control circuitry is configured to reduce electrical power output to the motor based on the signal indicating the increase in air pressure by: starting a timer for a predetermined amount of time and then reducing electrical power output to the motor if the signal indicates that the air pressure did not increase relative to a threshold amount during the counting of the timer, but not reducing electrical power output to the motor if the signal indicates that the pressure did increase relative to the threshold amount during the counting of the timer.

19. The sprayer of claim 15 , wherein the blower comprises a fan, an impeller, or a turbine that is rotated by the motor to generate the flow of pressurized air.

20. A method of controlling a sprayer comprising:
providing power to a motor of an air supply unit based on a signal output from a sensor, the air supply unit outputting a flow of pressurized air, th

Assignees

• Graco Minnesota Inc

Inventors

• Svendsen John M
• Olson Diane L

Classifications

• B05B7/2416 Primary

  characterised by the means for producing or supplying the atomising fluid, e.g. air hoses, air pumps, gas containers, compressors, fans, ventilators, their drives · CPC title

• B05B7/0081

  Apparatus supplied with low pressure gas, e.g. "hvlp"-guns; air supplied by a fan · CPC title

• B05B7/12

  designed to control volume of flow, e.g. with adjustable passages · CPC title

• B05B7/2472

  comprising several containers · CPC title

• B05B7/2478

  Gun with a container which, in normal use, is located above the gun · CPC title