Flow control systems and/or laundry machines including such flow control systems

• US 4,978,058 A
• Filed: 02/07/1989
• Issued: 12/18/1990
• Est. Priority Date: 02/09/1988
• Status: Expired due to Term

• Current Assignee: Fisher & Paykel Limited
• Original Assignee: Fisher & Paykel Limited
• Inventors: Duncan, Gerald, Greenman, Murray, Shacklock, Frank W.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/307,275
• Time in Patent Office: 679 Days
• Field of Search: 236/12.1, 236/12.11, 236/12.12, 236/12.14, 137/606, 137/624.2, 251/129.08
• US Class Current: 236/12.12
• CPC Class Codes: D06F 2105/04 from separate hot and cold water inlets
• CPC Class Codes: D06F 33/34 of water filling
• CPC Class Codes: D06F 39/088 Liquid supply arrangements
• CPC Class Codes: G05D 23/1393 characterised by the use of electric means

Abstract

A specific physical characteristic (temperature) of a mixture of two liquids in a mixing chamber (14) is controlled by progressively opening a valve member (35) of a selected valve (10,11) through which one of the liquids flows while the other liquid flows through the other valve, and if the temperature of the mixed liquids has not reached a desired level, the selected valve is left fully open while the other valve is progressively closed to adjust the temperature to that desired. The opening and closing of the valves is controlled in response to signals from a sensor in the mixing chamber.

Claims

1. A method of controlling temperature of a mixture of two liquids supplied to a mixing chamber, each liquid having a different temperature level and a first one of said liquids having the higher temperature level being caused to flow through a selected first valve and the second one of said liquids being caused to flow through a second valve to said mixing chamber, each of said valves having a valve seat, a spring loaded valve member spring loaded to a closed position against said valve seat and an electromagnet effective on energization to actuate said spring loaded valve member towards a fully open position and actuable by causing a current to flow through said electromagnet to cause said electromagnet to progressively open said valve member, said method comprising:

opening said second valve to a desired degree of opening;

controlling the current flowing in said electromagnet of said selected first valve in a manner so that the greater the current flowing the greater the flow of liquid through said selected first valve;

sensing the temperature in said mixing chamber and controlling the current flowing in said electromagnet of said selected first valve according to said temperature of the liquid in said mixing chamber in a manner such that said valve member of said selected first valve progressively opens or closes so that the temperature of said mixture of said two liquids flowing through said first and second valves is maintained equal to or approaching a desired level in said mixing chamber, and when said first valve is opened to the fully open position and the desired raised temperature in said mixing chamber has not been reached, progressively closing said second valve to further increase the temperature of liquid in said mixing chamber up to the temperature level of said first liquid when said desired temperature is equal to or higher than said first liquid temperature level.

2. A flow control system to control the temperature of a mixture of two liquids, a first liquid having a high temperature level and a second liquid having a low temperature level comprising:

a mixing chamber;

a first valve through which said first liquid flows to said mixing chamber;

a second valve through which said second liquid flows to said mixing chamber;

each of said valves being a proportional control valve comprising a valve seat, a spring loaded valve member spring loaded to a closed position against said valve seat, and an electromagnet means effective on energization to actuate said valve member towards a fully open position;

temperature sensing means positioned in said mixing chamber for sensing the temperature level of the mixing liquid in said mixing chamber;

second valve control means responsive to said sensing means to open on actuation thereof said second valve to a desired degree of opening; and

first valve control means responsive to said sensing means, so that in operation with said second valve opened to said desired degree, current flowing through said electromagnet means of said first valve is controlled by said first valve control means to desired levels responsive to signals from said sensing means in a manner such that said first valve is progressively opened or closed substantially according to current flowing in said electromagnet means thereof so that the temperature of mixed liquid in said mixing chamber is maintained equal to or approaching a desired temperature level, and when said desired temperature level is not reached with said first valve fully open and said second valve at said desired degree of opening, said second valve is progressively closed to increase the temperature of liquid in said mixing chamber up to the temperature of said first liquid when the desired temperature level in said mixing chamber is equal to or higher than said first liquid temperature level.

3. A flow control system as claimed in claim 2 wherein said temperature sensing means comprises a thermistor mounted in said mixing chamber.

4. A flow control system as claimed in claim 3 wherein:

a microprocessor is provided operatively connected to said temperature sensing means for acting in response to signals therefrom; and

the electromagnet means of each valve comprises a solenoid coil and a valve driving circuit, each valve driving circuit being connected to said microprocessor for receiving commands from said microprocessor for proportionally controlling the degree of opening of the valve controlled by the respective valve driving circuit.

5. Apparatus comprising a flow control system as claimed in claim 4 and a container, said container receiving mixed liquids from said flow control system.

6. Apparatus comprising a flow control system as claimed in claim 3 and a container, said container receiving mixed liquids from said flow control system.

7. A flow control system as claimed in claim 2 wherein:

a microprocessor is provided operatively connected to said temperature sensing means for acting in response to signals therefrom; and

the electromagnet means of each valve comprises a solenoid coil and a valve driving circuit, each valve driving circuit being connected to said microprocessor for receiving commands from said microprocessor for proportionally controlling the degree of opening of the valve controlled by the respective valve driving circuit.

8. Apparatus comprising a flow control system as claimed in claim 7 and a container, said container receiving mixed liquids from said flow control system.

9. A flow control system as claimed in claim 7 wherein said valve driving circuits and said microprocessor are arranged so that proportional control of only one of said valves is effected at any one time.

10. Apparatus comprising a flow control system as claimed in claim 9 and a container, said container receiving mixed liquids from said flow control system.

11. Apparatus comprising a flow control system as claimed in claim 2 and a container, said container receiving mixed liquids from said flow control system.