Flow control system

1. A method for using a central heating/cooling system comprising a plurality of consumer devices connected to a common source through a pipe system which provides for delivering a liquid medium, the consumer devices comprising heat exchange systems, water taps or heat exchange systems and water taps; the method comprising:

distributing the liquid medium from the common source through the pipe system to the heat exchange systems and thereby heating or cooling rooms of a building, and/or to the water taps for use by consumers;

controlling, by means of a control system, a flow of the liquid medium passing through a pipe part of the pipe system with at least one of the heat exchange systems or water taps;

sensing an actual medium flow through the pipe part with a flow sensor, and the sensor outputting an electrical signal indicative of the sensed actual medium flow to the control system;

directly comparing the sensed flow with a set flow and outputting a control signal related to the direct comparison;

adjusting an adjustable orifice in said pipe part by means of an orifice adjusting system in response to the control signal; and

performing a real-time software-wise correction of a characteristic curve of the orifice adjusting system to compensate for pressure variations in said pipe part,

wherein the steps of directly comparing the sensed flow with a set flow and outputting a control signal and performing a real-time software-wise correction of a characteristic curve of the orifice adjusting system are done by the control system.

2. The method of claim 1 , further comprising:

continuously adjusting the adjustable orifice and correcting the characteristic curve based on the sensed actual medium flow.

3. The method of claim 1 , wherein the set medium flow varies between 0 and 100% Vnom, wherein Vnom is the maximum medium flow for the adjustable orifice.

4. The method of claim 1 , wherein the step of sensing an actual medium flow through the pipe part comprises: sensing an actual medium flow through the pipe part at a point in front of the adjustable orifice.

5. The method of claim 1 , wherein the step of sensing an actual medium flow through the pipe part comprises sensing an actual medium flow through the pipe part at a point behind the adjustable orifice and spaced by at least a quieting section for attenuating turbulence in the medium caused by the adjustable orifice.

6. The method of claim 1 , wherein the orifice adjusting system comprises a three-way valve located at an intersection of a supply pipe of the pipe system, provided for supplying the medium from the common source to at least one of the consumer devices, and a bypass pipe bypassing the at least one consumer device.

7. The method of claim 1 , wherein the method is performed without first calibrating the system.

8. The method of claim 1 , further comprising the step of

determining heat delivered by one of the heat exchange systems or water taps.

9. The method of claim 1 , wherein the set flow is derived from a setting or from a central control unit.

10. The method of claim 1 , wherein the flow sensor is an ultrasound flow sensor.

11. A method for operating a flow control system comprising an adjustable orifice in a pipe part which is adjustable between a zero medium flow 0 and a maximum medium flow Vnom, the method comprising steps:

a) setting an upper limit for the medium flow to Vmax wherein Vmax is less than Vnom;

b) supplying a liquid medium from a common source through the pipe part to at least one heat exchange system and thereby heating or cooling a room of a building and/or to at least one water tap for use by a consumer;

c) sensing an actual medium flow through the pipe part and outputting an electrical signal indicative of the sensed actual medium flow;

d) directly comparing the sensed medium flow with a set medium flow and outputting a control signal related to the direct comparison;

e) using an orifice adjusting system to adjust the adjustable orifice in the pipe part in response to the control signal; and

f) performing a correction of a characteristic curve of the orifice adjusting system over the new operating range up to Vmax.

12. The method of claim 11 , wherein step f) of performing a correction of a characteristic curve of the orifice adjusting system comprises updating the characteristic curve to be accurate over the range of medium flow of 0 to Vmax.

13. The method of claim 12 , wherein the characteristic curve is an equal-percentage characteristic curve in at least part of the range.

14. The method of claim 11 , wherein the method operates a flow control system over a system with a plurality of sections and/or levels and the method compensates for pressure variations over each section and/or level.

15. The method of claim 11 , wherein the step of performing a correction of a characteristic curve is performed using software.

16. The method of claim 11 , further comprising:

continuously adjusting the adjustable orifice over the range of medium flow of 0 to Vmax based on the sensed actual medium flow and the corrected characteristic curve.

17. The method of claim 11 , wherein Vmax is stored in a control unit.

18. The method of claim 11 , wherein the orifice adjusting system comprises a system which adjusts a flow control valve.

19. A method for operating a pressure-independent flow control system, the method comprising steps:

a) supplying a liquid medium from a common source through a pipe part to at least one heat exchange system and thereby heating or cooling a room of a building and/or to a water tap for use by a consumer;

b) sensing an actual medium flow through a pipe part and outputting an electrical signal indicative of the sensed actual medium flow;

c) directly comparing the sensed medium flow with a set medium flow and outputting a control signal related to the direct comparison;

d) using an orifice adjusting system to adjust an adjustable orifice in a pipe part in response to the control signal; and

e) performing a real-time software-wise correction of a characteristic curve of the orifice adjusting system.