Pressure washer with heat exchanger

A high pressure hot water cleaning system which includes a source of water flowing to a pressure valve to allow the system to come online, providing a tank for receiving the water, the tank having an inner portion, and an outer jacket portion, a water heater, a pump for pressurizing the water, and a pressure wand for flowing the hot, pressurized water for cleaning. The system further provides a means to allow the water to cool when the wand is disengaged. This means includes a flow line from the pump to the inner tank portion of the water tank, where the hot water is cooled by the ambient water in the tank jacket portion, and returning the cooler water into the pump during the idle period. Further, there is provided a timer which is activated by a flow switch when the water flow is interrupted, so that after a period of time of idle time, the system is automatically shut down and must be manually reactivated.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to high pressure hot water washers. More 
particularly, the present invention relates to a hot water high pressure 
washing system incorporating a heat exchanger therein working in 
combination with a timer mechanism to reduce the temperature of the water 
when the washer is idle over a given period of time. 
2. General Background 
In the art of high pressure washers for cleaning grease, oil, or other 
compounds, such as dried oil-based muds from mechanical components, as for 
example, rig machinery, or the like, it is necessary that in addition to 
the water being at high pressures, that the water be heated, to a 
temperature, for example 150 degrees Fahrenheit. Such cleaning systems 
currently in the art utilize water from a source entering the system, and 
engaging a pressure switch in order to activate the system. The water 
flows to a water heater for heating the water to the desired temperature. 
The heated water then enters a pump, which pressures the water stream, so 
that when a pressure washer wand is manually activated, the high pressure 
stream of hot water flows from the wand and cleans the component to be 
cleaned. However, oftentimes, during cleaning, the person operating the 
wand, must interrupt the work for lengths of time. During this time the 
hot water continues to circulate within a closed loop in the head of the 
pump until the pressure wand is reactivated, unless the water source is 
turned off. The problem with this arrangement is that the water will 
continue to be circulated at that high temperature and will then "spike" 
at a much higher temperature, e.g. 180 degrees fahrenheit, during the 
closed loop cycle. This spiking causes damage to the internal seals, etc. 
of the pump head and usually results in shortening the life of the pump 
and ultimately incapacitating the pump. 
The problem cannot always be avoided simply by turning off the source of 
water to the pump, since this is not always a convenient means to operate 
the system. In order to avoid damage to pumps, what is needed is a means 
to reduce the temperature of the water sufficiently so that the pump 
system is not damaged while the pump is in idle, but does not require 
shutting down the water source entirely. 
SUMMARY OF THE PRESENT INVENTION 
The apparatus and system of the present invention solves the problems in 
the art in a simple and straightforward manner. What is provided is a high 
pressure hot water cleaning system which includes a source of water 
flowing at ambient temperature to a pressure valve to allow the system to 
come online; providing a tank for receiving the water, the tank having an 
inner portion, and an outer jacket portion; providing a water heater; a 
pump for pressurizing the water, a pressure washer wand for receiving the 
pressurized water from the pump, for cleaning. The system further provides 
a means to allow the pump to cool when the wand is manually disengaged. 
This means includes a flow line extending from the pump to the inner 
portion of the water tank, where the hot water is cooled by the ambient 
water in the outer tank jacket portion, before it returns to the pump and 
is recirculated during the idle period. Simultaneously, a flow switch 
senses the interruption in the water flow, and automatically activates a 
timer, so that after a period of idle time, the timer automatically shuts 
down the system which must be manually reactivated. 
Therefore, it is a principal object of the present invention to provide a 
high pressure hot water cleaning system which allows for immediate cooling 
down of the water flowing over the pump head the instant idle time begins; 
It is a further principal object of the present invention to provide a heat 
exchange mechanism in the system so that when the system is idle, the hot 
water flowing over the pump is cooled sufficiently to eliminate heat spike 
damage to the pump head; 
It is a further object of the present invention to provide a high pressure 
hot water cleaning system which includes a flow switch to deactivate a 
timer working in conjunction with a heat exchanger, so that when the 
system is put on idle, the timer is activated by the flow switch to allow 
the system to remain idle for a certain period of time until the system is 
automatically shut down, yet during the idle time period, maintaining the 
water at a sufficiently low temperature to eliminate the potential of 
damage to the components within a system pump during the idle time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 illustrates the preferred embodiment of the apparatus and system of 
the present invention by the numeral 10. Prior to a discussion of the 
current invention, reference is made to FIG. 2, which illustrates in 
schematic view a prior art system which is currently in use in the art. 
This system will be referenced as System 100. 
As illustrated in FIG. 2, System 100 includes a source of water (arrow 102) 
entering through a flow line 104, and a flow valve 106. The water flows to 
a sensor means 108, which senses the pressure within flow line 104, of the 
water therein. In normal circumstances, this pressure sensor 108 is 
utilized to activate the System 100, when the pressure of the water is at 
least fifteen pounds per square inch at point 110. In addition to the 
pressure sensor, there is usually a manually activated timer 112, which is 
utilized to shut the system down at a specific time set manually by the 
operator. Following the sensing of the water pressure in line 104, by 
pressure sensor 108, the system becomes operable, and water will then flow 
through second branch of flow line 114, to a water heater 116. Water 
heater 116, is of a type that can be commercially obtained, and is 
utilized to heat the water to a temperature of approximately 150 degrees 
fahrenheit. The water then exits water heater 116 through flow line 118, 
and enters the pumping unit 120 at the low pressure side 121. The pump 120 
comprises a standard single stroke piston-driven pump, which increases the 
pressure of the water flowing over the pump head 119, and out of the high 
pressure side 123 of the pump via line 122. The pressurized water would 
flow to pressure washer wand 124, so that the hot pressurized water 125 is 
able to clean components that may be ladened with oil or other types of 
debris. The pump 120 would be driven by an electric motor 126, as seen via 
belt members 128, to operate the piston driven pump. As was explained 
earlier, this system is quite common in the art, and has significant 
shortcomings. 
As further illustrated in FIG. 2, when the user of the pressure wand 124 
must interrupt use, wand 124 is turned off, and the water cannot exit wand 
124, but is diverted into a closed loop 127, which then allows water to 
continue to circulate within the closed loop 127 and through the head 119 
of the pump 120 during nonuse. The problem with such a system is that over 
a given amount of time, the water which is entering the pump at 150 
degrees and which continues to circulate within the pump head, tends to 
increase in temperature, and cause a "spiking" of the water in the 
neighborhood of 180 degrees fahrenheit. When this occurs, the components 
within the pump head 119, such as the packing and other types of seals, 
would tend to crystalize and eventually disintegrate under the continuous 
heat. Therefore, over time the life of pump 120 is reduced significantly, 
and therefore the pump 120 must be discarded and replaced at a time much 
earlier than what could be its life span. 
FIG. 1 illustrates the improved system of the present invention to overcome 
this and other problems. What is provided in system 10 is a water inlet 
line 12, flowing through a water intake valve 14, and into a principal 
flow line 16. Water in flow line 16 is then diverted into a first flow 
line 18 which engages a pressure sensor 20. As in the prior art, the 
pressure sensor 20 is so rated so that if the water is at least 15 degrees 
per square inch in pressure, the pressure sensor 20 will activate the 
system for use as seen in FIG. 1. Further, water is diverted into a second 
flow line 22, which allows it to flow through a flow switch 24, which flow 
switch is positioned in line with a timer 26. As long as water is flowing 
through flow switch 24, which indicates that the system is in use, then 
the timer 26 will remain inactive. Once the water stops flowing within 
line 22, for reasons which will be explained further, the timer 26 then 
will automatically be set at thirty minutes and after a thirty minute time 
span, the timer 26 will cause the entire system to shut down. This will be 
explained further. 
Returning now to the system itself, after the water has flowed past flow 
switch 24, through line 22, it then enters a heat exchange means 30. This 
heat exchange means comprises a tank 32, having a first annular wall 34, 
and an inner tank space 36, having an interior annular wall 38. The 
interior annular wall 38, defines an inner cooling tank 40, and there is 
defined an outer cooling tank 42 in the annular space 44 between the first 
annular wall 34 and the interior wall 38. As illustrated in FIG. 1, water 
flowing through line 22, fills the outer jacket 42. The water in outer 
jacket 42 then flows into a water heater 50, while the water in inner tank 
40 remains idle and cooled at ambient temperature. Water heater 50, as in 
the prior art, is a convention heater, which heats the water up to at 
least 150 degrees fahrenheit and is usually heated via an electric coil or 
the like to avoid any explosions in the system which may occur through 
open flames. Once the water is heated to the proper temperature, it flows 
via exit flow line 52 into the low pressure side 54 of pump 56. Again, 
pump 56 is a convention type pump as is utilized in the prior art, and is 
driven by an electric motor 58, via belt members 60, to operate a piston 
within pump 56, for pressurizing the water therein. After the water has 
entered the head 62 of pump 56, it exits on the high pressure side 55 of 
pump head 62. The pressurized water then flow through line 63 so that when 
pressure wand 64 is activated, hot water 65 flows from wand 64, under 
pressure to clean the components that need to be cleaned. 
In the event that the user of the system must interrupt the flow of water, 
once the wand 64 is released and water can no longer flow through wand 64, 
the water is then diverted into a first line 66, which allows the water to 
flow into inner tank 40, which contains cool water. This water entering 
the inner tank 40 is approximately 150 degrees fahrenheit but cools down 
and returns back through return line 70 into pump head 62. As is seen from 
the drawing in FIG. 1, the inner tank 40 is surrounded by ambient 
temperature water which is flowed from the flow line 22 into the outer 
tank jacket 42 prior to it entering the heater 50. Therefore, as the 
heated water flows from the pump head 62 through line 66 into the inner 
tank 40, there is a heat exchange effect between the inner tank 40 and the 
outer tank jacket 42, with the ambient temperature in the outer tank 
jacket 42 lowering the temperature of the water in the inner tank 40 
within seconds. When this is accomplished, the water then returning and 
recirculating through the head 62 of pump 56 is much cooler and reduces 
the temperature of the head to a temperature of 110 to 120 degrees 
fahrenheit, and therefore does not result in any damage to the pump head 
62, since the components of the pump head 62 are rated for such high 
temperatures. 
As was stated earlier, when pressure wand 64 is deactivated, there is no 
longer water flowing through line 22, and therefore the flow switch 24, 
when sensing the non-flow of water, immediately activates the timer 26 for 
a thirty minute time cycle. During this thirty minutes of non-use, the 
heat exchanger 30 maintains the water at the desired level below 150 
degrees fahrenheit. At the end of the thirty minutes, the timer goes off 
and the system is automatically shut down so that the water is no longer 
being heated. In order to be brought back on line, the system will have to 
be manually reactivated. Should the user of the system return within that 
thirty minute time cycle and the nozzle is re-engaged, then the pressure 
sensor 20 will sense the flow of water and will reactivate the system with 
the timer 26 being reset back at thirty minutes until the flow switch 24 
would activate it once more. 
Therefore, it is important to understand that the heat exchanger 30 enables 
the user of the system to interrupt use for a given period of time, i.e. 
thirty minutes, without the system shutting down. However, during this 
period of nonuse, the heated water within the system, i.e., particularly 
in the pump area, is reduced in temperature via the heat exchanger 30 in 
the inner tank 40 and the outer tank jacket 42 in order to protect the 
life of the pump. In addition, and as important, is the fact that the flow 
switch 24, when sensing the interruption and flow of water through it, 
will automatically activate the thirty minute timer 26. This is a critical 
part of the combination in view of the fact that without the thirty minute 
timer 26, the heat exchange portion of the system would continue to do its 
job. However, over an extended period of time there would eventually 
result in the water temperature continuing to get gradually higher and 
ultimately spiking as in the current state of the art. Therefore it is 
critical that the flow switch and timer work in conjunction with the heat 
exchanger to establish a system that is vastly improved over the current 
state of the art. 
Certain components in the system are standard off the shelf items, such as 
the water heater which utilizes an electric 440 volt heating element. The 
system is further explosion proof. i.e., the flow switches that are 
activated are all electronic, and the timer is enclosed inside an 
explosion-proof enclosure. 
The following table lists the part numbers and part descriptions as used 
herein and in the drawings attached hereto. 
______________________________________ 
TS LIST 
Description Part No. 
______________________________________ 
system 10 
inlet line 12 
intake valve 14 
principal flow line 
16 
first flow line 18 
pressure sensor 20 
second flow line 22 
flow switch 24 
timer 26 
heat exchange means 
30 
tank 32 
first annular wall 34 
inner tank space 36 
inner annular wall 38 
inner cooling tank portion 
40 
outer tank jacket 42 
annular space 44 
water heater 50 
flow line 52 
low pressure side 54 
high pressure side 55 
pump 56 
electric motor 58 
belt members 60 
pump head 62 
flow line 63 
pressure water wand 
64 
hot water 65 
first line 66 
return line 70 
system 100 
arrow 102 
flow line 104 
flow valve 106 
sensor means 108 
point 110 
timer 112 
flow line 114 
water heater 116 
flow line 118 
pump head 119 
pumping unit 120 
line 122 
high pressure side 123 
pressure washer wand 
124 
hot water 125 
electric motor 126 
closed loop 127 
belt members 128 
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Because many varying and different embodiments may be made within the scope 
of the inventive concept herein taught, and because many modifications may 
be made in the embodiments herein detailed in accordance with the 
descriptive requirement of the law, it is to be understood that the 
details herein are to be interpreted as illustrative and not in a limiting 
sense.