Pressure washer with duty cycle temperature controller and method
First Claim
1. A pressure washer for use by an operator comprising:
- a heat exchanger having a water input adapted to connect to a water source and having a water output providing discharge water;
a cycle timer responsive to the flow of water through the heat exchanger;
a burner in thermodynamic communication with the heat exchanger for applying heat to the heat exchanger and to the water in the heat exchanger, said burner having a fuel input connecting a fuel source to the burner; and
a fuel switch responsive to the cycle timer, said fuel switch selectively allowing fuel from the fuel source to be supplied to the burner via the fuel input, whereby the cycle timer controls a duty cycle of the fuel switch and thereby controls temperature of the water in the heat exchanger.
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Accused Products
Abstract
A pressure washer for use by an operator. A heat exchanger has a water input adapted to connect to a water source and has a water output providing discharge water. A water pump supples water to the heat. A temperature selector is responsive to operator. A burner in thermodynamic communication with the heat exchanger applies heat to the heat exchanger and the water in the heat exchanger. The burner has a fuel input connecting a fuel source to the burner. A fuel switch selectively allows fuel from the fuel source to be supplied to the combustion chamber via the fuel input. A duty cycle timer has a uniform duty cycle and is energized when water flows through the heat exchanger. The duty cycle timer is responsive to the temperature selection switch to vary its duty cycle as a function of the operator input provided to the temperature selector. The duty cycle timer controls the fuel switch to supply fuel to the combustion chamber according to the duty cycle of the duty cycle timer whereby the duty cycle timer controls the burner and thereby controls temperature of the water in the heat exchanger. Preferably, the duty cycle has a minimum on time to maintain burner efficiency.
68 Citations
16 Claims
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1. A pressure washer for use by an operator comprising:
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a heat exchanger having a water input adapted to connect to a water source and having a water output providing discharge water;
a cycle timer responsive to the flow of water through the heat exchanger;
a burner in thermodynamic communication with the heat exchanger for applying heat to the heat exchanger and to the water in the heat exchanger, said burner having a fuel input connecting a fuel source to the burner; and
a fuel switch responsive to the cycle timer, said fuel switch selectively allowing fuel from the fuel source to be supplied to the burner via the fuel input, whereby the cycle timer controls a duty cycle of the fuel switch and thereby controls temperature of the water in the heat exchanger. - View Dependent Claims (2, 3, 4)
an ignition source igniting the fuel supplied from the fuel source to the burner;
a fuel pump associated with the fuel input, said fuel pump selectively controlling a quantity of fuel supplied from the fuel source to the burner; and
a nozzle associated with the fuel input, said nozzle atomizing the fuel supplied from the fuel to the burner.
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4. The pressure washer of claim 1 wherein the cycle timer comprises a microprocessor.
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5. A pressure washer for use by an operator comprising:
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a heat exchanger having a water input adapted to connect to a water source and having a water output providing discharge water;
a cycle timer responsive to the flow of water flow through the heat exchanger;
a burner in thermodynamic communication with the heat exchanger for applying heat to the heat exchanger and to the water in the heat exchanger, said burner having a fuel input connecting a fuel source to the burner;
a fuel switch responsive to the cycle timer, said fuel switch selectively allowing fuel from the fuel source to be supplied to the burner via the fuel input, such that the cycle timer controls the duty cycle of the fuel switch and thereby controls temperature of the water in the heat exchanger;
a water flow valve for selectively controlling the flow of water through the heat exchanger, said water flow valve having an open state in which water flows through the heat exchanger;
a water pump supplying water to the heat exchanger when the water flow valve is in the open state;
a water flow switch sensing water flow into the heat exchanger; and
wherein said cycle timer is responsive to the water flow switch and is energized when the water flow switch senses water flow into the heat exchanger. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
an ignition source igniting the fuel supplied from the fuel source to the burner;
a fuel pump associated with the fuel input, said fuel pump selectively controlling a quantity of fuel supplied from the fuel source to the burner; and
a nozzle associated with the fuel input, said nozzle atomizing the fuel supplied from the fuel to the burner.
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12. The pressure washer of claim 11 further comprising a fuel pressure regulator selectively controlling the fuel pump thereby causing pressure regulated fuel to be supplied to the burner such that the amount of fuel oxidized in the burner per unit of time is a function of the pressure of the fuel supplied.
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13. The pressure washer of claim 11 wherein the nozzle further controls a pressure of the fuel supplied from the fuel source to the burner such that the amount of fuel oxidized in the burner per unit of time is a function of a size of the fuel nozzle.
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14. A pressure washer for use by an operator comprising:
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a heat exchanger having a water input adapted to connect to a water source and having a water output providing discharge water;
a water pump supplying water to the heat exchanger;
a temperature selector responsive to operator input;
a burner in thermodynamic communication with the heat exchanger for applying heat to the heat exchanger and the water in the heat exchanger, said burner having a fuel input connecting a fuel source to the burner;
a fuel switch selectively allowing fuel from the fuel source to be supplied to the burner via the fuel input;
a duty cycle timer having a uniform duty cycle and being energized when water flows through the heat exchanger, said duty cycle timer being responsive to the temperature selection switch to vary its duty cycle as a function of the operator input provided to the temperature selector, and wherein the duty cycle timer controls the fuel switch to supply fuel to the burner according to the duty cycle of the duty cycle timer whereby the duty cycle timer controls the burner and thereby controls temperature of the water in the heat exchanger. - View Dependent Claims (15)
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16. A pressure washer for use by an operator comprising:
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a heat exchanger having a water input adapted to connect to a water source and having a water output providing discharge water;
a water pump supplying water to the heat exchanger;
a temperature selection switch responsive to an operator input indicating a desired temperature of the discharge water;
a burner in thermodynamic communication with the heat exchanger for applying heat to the heat exchanger and the water in the heat exchanger, said burner having a fuel input connecting a fuel source to the burner;
a fuel switch selectively allowing fuel from the fuel source to be supplied to the burner via the fuel input; and
a processor being responsive to the temperature selection switch to vary the duty cycle of the fuel switch as a function of the operator input provided to the temperature selector such that the processor controls the duty cycle of the fuel switch as a function of the desired temperature and wherein the duty cycle has an off time and a minimum on time and the temperature selection switch varies at least the off time of the duty cycle.
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Specification