Pump and pump control circuit apparatus and method

• US 20080181788A1
• Filed: 10/31/2007
• Published: 07/31/2008
• Est. Priority Date: 11/26/2001
• Status: Active Grant

• Current Assignee: Humberto V. Meza, Nikhil Jitendra Gandhi, Quang Minh Truong
• Original Assignee: Humberto V. Meza, Nikhil Jitendra Gandhi, Quang Minh Truong
• Inventors: Meza, Humberto V., Truong, Quang Minh, Gandhi, Nikhil Jitendra
• Granted Patent: US 8,641,383 B2
• Time in Patent Office: Days
• US Class Current: 417/44.2
• CPC Class Codes: F04B 2203/0201 Current
• CPC Class Codes: F04B 2203/0208 Power
• CPC Class Codes: F04B 2205/04 Pressure in the outlet chamber
• CPC Class Codes: F04B 43/0054 particularities of the flexible members
• CPC Class Codes: F04B 43/0081 systems, control, safety measures
• CPC Class Codes: F04B 43/04 Pumps having electric drive
• CPC Class Codes: F04B 49/065 and making use of computers

Abstract

A method and apparatus for a pump and a pump control system. The apparatus includes pistons integrally formed in a diaphragm and coupled to the diaphragm by convolutes. The convolutes have a bottom surface angled with respect to a top surface of the pistons. The apparatus also includes an outlet port positioned tangentially with respect to the perimeter of an outlet chamber. The apparatus further includes a non-mechanical pressure sensor and a temperature sensor coupled to a pump control system. For the method of the invention, the microcontroller provides a pulse-width modulation control signal to an output power stage in order to selectively control the power provided to the pump. The control signal is based on the pressure within the pump, the current being provided to the pump, the voltage level of the battery, and the temperature of the pump.

Claims

1. A method of controlling a pump, the method comprising:

sensing a pressure in the pump;

reducing power to the pump when the sensed pressure is approaching a shut-off pressure during a low-flow mode until the sensed pressure is less than the shut-off pressure; and

turning the pump off when the sensed pressure is greater than the shut-off pressure and there is no flow through the pump.

2. The method of claim 1, wherein sensing a pressure in the pump includes sensing a pressure in an outlet chamber in the pump.

3. The method of claim 1, and further comprising generating a pulse-width modulation control signal based on the sensed pressure.

4. The method of claim 3, and further comprising generating a pulse-width modulation control signal having a duty cycle, reducing the duty cycle in order to reduce power supplied to the pump, and increasing the duty cycle in order to increase power supplied to the pump.

5. The method of claim 3, and further comprising amplifying and filtering the sensed pressure before generating a pulse-width modulation control signal based on the sensed pressure.

6. A pump control circuit for use with a pump, the circuit comprising:

an electronic pressure sensor capable of sensing an actual pressure inside the pump;

a current sensing circuit capable of sensing a current being provided to the pump;

a microcontroller coupled to the pressure sensor and the current sensing circuit, the microcontroller programmed to determine a current limit threshold based on the sensed pressure, and the microcontroller programmed to generate a high control signal if the sensed current is less than the current limit threshold and a low control signal if the sensed current is greater than the current limit threshold; and

an output power stage coupled to receive the control signal from the microcontroller so that if the control signal is a low control signal the power provided to the pump is reduced until the sensed current is less than the current limit threshold.

7. The pump control circuit of claim 6, wherein the pressure sensor is capable of sensing the pressure in an outlet chamber in the pump.

8. The pump control circuit of claim 6, wherein an amplifier and filter circuit is coupled between the pressure sensor and the microprocessor.

9. The pump control circuit of claim 6, wherein the output power stage includes a comparator circuit which determines whether the control signal is a high control signal or a low control signal, and wherein an output of the comparator circuit is positive for a high control signal and negative for a low control signal.

10. A method of controlling a pump, the method comprising:

sensing a pressure in the pump;

determining a current limit threshold based on the sensed pressure;

sensing a current being provided to the pump;

comparing the sensed current to the current limit threshold; and

providing power to the pump if the sensed current is less than the current limit threshold and reducing the power provided to the pump if the sensed current is greater than the current limit threshold until the sensed current is less than the current limit threshold.