Fluid flow and temperature control apparatus

• US 5,358,177 A
• Filed: 08/10/1993
• Issued: 10/25/1994
• Est. Priority Date: 05/15/1990
• Status: Expired due to Term

• Current Assignee: The Computer Shower Company Limited
• Original Assignee: The Computer Shower Company Limited
• Inventors: Cashmore, Peter R.
• Primary Examiner(s): Sollecito, John M.
• Application Number:
  US08/104,409
• Time in Patent Office: 441 Days
• Field of Search: 236/12.12, 236/93 R, 137/606, 137/486, 137/561 R, 137/332, 364/510
• US Class Current: 236/12.12
• CPC Class Codes: G05D 23/1393 characterised by the use of electric means
• CPC Class Codes: Y10T 137/6307 Turbine on valve
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow
• CPC Class Codes: Y10T 137/87684 Valve in each inlet

Abstract

Apparatus is provided to supply a liquid, for example water, at a constant temperature, for example to a shower by mixing two supplies of the liquid, one hot and the other cold. Control of the output temperature is effected by measuring and controlling the flow rate in one or both of the supplies by way of flow meters having a rapid response time and motor driven valves.

In the case where the flow rates in both supplies are measured and controlled it is possible further to control the output flow rate in addition to and independently from the output temperature, also by controlling the flow rates in the supplies.

Further accuracy may be achieved by sensing the input supply temperatures in addition to the flow rates.

Claims

1. Apparatus for providing liquid at a defined temperature from a mixture of

a first supply of liquid having a temperature higher than said defined temperature, and

a second supply of said liquid having a temperature lower than said defined temperature, the apparatus comprising:

flow rate sensing means located in at least one said supply for sensing the flow rate in said one of said first and second supplies;

adjustment means arranged to control the flow rate in said one of said first and second supplies; and

control means responsive to said flor rate sensing means to control said adjustment means whereby to adjust the flow rate and maintain the defined temperature of the mixed liquid.

2. Apparatus as claimed in claim 1 wherein said flow sensing means comprises a flow rate meter arranged to provide an electrical signal functionally related to the volume flow rate through said one supply, and said control means comprises an input arranged to receive said electrical signal.

3. Apparatus as defined in claim 1 wherein said adjustment means comprises a valve and a stepper motor, said stepper motor being arranged to receive control signals from said control means and to open and close said valve.

4. Apparatus as defined in claim 1 wherein said control means comprises a microprocessor.

5. Apparatus as defined in claim 1 arranged to provide water to a domestic shower.

6. Apparatus as defined in claim 2 wherein said adjustment means comprises a valve and a stepper motor, said stepper motor being arranged to receive control signals from said control means and to open and close said valve.

7. Apparatus arranged to provide liquid at a defined temperature comprising:

a first supply of said liquid having a temperature higher than said defined temperature,

a second supply of said liquid having a temperature longer than said defined temperature,

a mixing chamber having two inputs and an output, said two inputs being arranged to receive liquid from said two supplies respectively and said output being arranged to provide a mixture of the liquids from said two supplies,

first flow sensing means arranged to sense the flow rate in said first supply,

second flow sensing means arranged to sense the flow rate in said second supply,

first adjustable means arranged to control the flow rate in said first supply,

second adjustable means arranged to control the flow rate in said second supply, and

control means responsive to said first and second flow sensing means to control said first and second adjustable means whereby to maintain the temperature of the liquid at the output from said mixing chamber.

8. Apparatus as defined in claim 7 wherein said first and second flow sensing means each comprise a flow meter arranged to provide an electrical signal functionally related to the volume flow rate through the respective supply and said control means comprises inputs arranged to receive the electrical signals from said first and second sensing means.

9. Apparatus as defined in claim 8 wherein said flow meter comprises a turbine arranged to be rotated by flow through the meter and a light source and a photosensitive device arranged such that a light beam from said light source falls on said photosensitive device and is alternately interrupted and restored during rotation of said turbine.

10. Apparatus as defined in claim 7 wherein said first and second adjustable means each comprise a valve and a stepper motor, said stepper motor being arranged to receive control signals from said control means and to open and close said valve.

11. Apparatus as defined in claim 7 wherein said control means is further adapted to control said first and second adjustable means whereby to maintain the flow rate of the liquid at the output from said mixing chamber at a determined magnitude.

12. Apparatus as defined in claim 7 wherein said control means comprises a microprocessor.

13. Apparatus as defined in claim 7 further comprising first and second temperature sensing means arranged to detect the temperature of said first and second supplies respectively.

14. Apparatus as defined in claim 7 arranged to provide water to a domestic shower.

15. Apparatus for providing liquid at a defined temperature from a mixture of a first supply of liquid having a temperature higher than said defined temperature and a second supply of said liquid having a temperature lower than said defined temperature, the apparatus comprising:

flow rate sensing means located in at least one of said first and second supplies for sensing flowrate in said one of said first and second supplies and emitting an electrical signal indicative of said flowrate;

adjustment means in the form of a valve means and a stepper motor arranged to control the flowrate in said one of said first and second supplies;

control means responsive to said flowrate sensing means and connected to the stepper motor for controlling said adjustment valve means to adjust the flowrate and maintain said defined temperature of mixed liquid, the control means being in the form of an electronic data processing means having as an input the electrical output signal from the flowrate sensing means for computing the ratio of the flowrates in said first and second supplies; and

wherein there is not temperature sensor for sensing the mixed liquid temperature and hence the electronic data processing means has no input for a signal indicative of mixed liquid temperatures.