Pumps – Condition responsive control of pump drive motor – With condition responsive control of pump fluid valve
Patent
1991-07-24
1992-12-29
Bertsch, Richard A.
Pumps
Condition responsive control of pump drive motor
With condition responsive control of pump fluid valve
417 43, 417 34, F04B 4908
Patent
active
051747235
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a high-pressure cleaning appliance comprising a high-pressure pump driven by an internal combustion engine, a bypass line leading from the pressure line of the pump to the intake side of the pump and opening when the pressure line is closed, and a pressure sensor in the pressure line.
The high-pressure pump of high-pressure cleaning appliances designed for mobile operation is often driven by an internal combustion engine. When the spray line is open, the internal combustion engine drives the pump with the power required for operation. Closure of the spray gun of the high-pressure pump would result in intensive heating-up of the pump which no longer has any liquid flowing through it.
For this reason, it is known to provide high-pressure cleaning pumps with a bypass which leads back from the pressure line to the intake side of the pump when the pressure line is closed so that the pump then conveys liquid in a circuit. The power required by the pump for this bypass mode is considerably lower than the power required for normal operation. The object of the invention is to so improve a high-pressure cleaning appliance of the generic kind that the power fed to the pump by the internal combustion engine is automatically reduced when the pressure line is closed.
This object is accomplished in a high-pressure cleaning appliance of the kind described at the beginning in accordance with the invention by the pressure sensor reducing the speed of the internal combustion engine immediately when the pressure in the pressure line drops below a certain value, and by a flow monitor being arranged in the pressure line to open the bypass line when there is an absence of flow.
A drop in the pressure in the pressure line occurs when the bypass line is opened so that by way of the reduction in the speed of the internal combustion engine a reduction in the power transmitted to the pump is thereby also automatically achieved. Conversely, the pressure in the pressure line rises again when the bypass line is closed as a result of the pressure drop occurring initially when the spray gun is opened. This rise in pressure then leads via the pressure sensor to a rise in the speed of the internal combustion engine again and hence to transmission of the power required for normal operation to the high-pressure pump. It is very advantageous that the opening and closing of the bypass line is controlled in dependence upon the flow by a flow sensor which detects the flow in the pressure line. Once the flow through the pressure line stops owing to closure of the spray gun, the bypass line is opened, once the flow through the pressure line recommences owing to opening of the spray gun, the bypass line is immediately closed. This immediate closing and opening of the bypass line in dependence upon the flow in the pressure line promotes the pressure changes in the pressure line and hence the change in speed of the internal combustion engine.
It is already known per se from U.S. Pat. No. 3,977,603 to control the speed of an internal combustion engine in dependence upon the pressure of the liquid conveyed, but there is no indication in the known system that the liquid conveyed in the idle mode is to be conducted in a bypass line. Hence corresponding control means, in particular a flow monitor for opening and closing the bypass line, are also missing.
It is also advantageous that a corresponding reduction of the speed occurs not only upon closure of the spray gun and the resulting opening of the bypass line, but also in the event of unforeseen disturbances, for example, if the high-pressure tube should burst or be torn off, as, in this case, too, the pressure prevailing in the pressure line drops below the pressure necessary for the reduction of the speed.
It is particularly advantageous for the pressure sensor to adjust the throttle lever system of the internal combustion engine in the direction towards an increase in the speed when the certain pressure value is exceeded. This intervention in the throttle lever system of the in
REFERENCES:
patent: 3977603 (1976-08-01), Magee, Jr.
patent: 4238073 (1980-12-01), Liska
patent: 4353336 (1982-10-01), Mowbray
patent: 4527953 (1985-07-01), Baker et al.
patent: 4545740 (1985-10-01), Nishikiori et al.
patent: 5035580 (1991-07-01), Simonette
Groger Betram
Komp Helmut
Schwaderer Rudi
Alfred Karcher GmbH & Co.
Bertsch Richard A.
Lipsitz Barry R.
Scheuermann David W.
LandOfFree
High-pressure cleaning appliance does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High-pressure cleaning appliance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-pressure cleaning appliance will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1883760