Pressurized steam boilers and their control
AssigneeAutoflame Engineering Limited
InventorsBrendan Kemp, Paul James Nichols
Life of this patent
Estimating the term…
Abstract
A method of controlling the operation of a pressurised steam boiler (50) heated by a burner (20), which includes the steps of a) monitoring the level of water in the boiler (50), b) monitoring the pressure of steam in the boiler (50), c) monitoring the firing rate of the burner (20), and d) controlling the flow rate of water into the boiler (50) having regard to the signals resulting from a) and b) and, at least for some signal conditions, also having regard to signals resulting from c). The level of water is detected by a pair of capacitance probe assemblies (58A and 58B).
Claims60
A method of controlling the operation of a pressurised steam boiler heated by a burner, the method including the following steps:
- a) monitoring the level of water in the boiler,
- b) monitoring the pressure of steam in the boiler,
- c) monitoring the firing rate of the burner, and
- d) controlling the flow rate of water into the boiler having regard to the signals resulting from a) and b) and, at least for some signal conditions, also having regard to signals resulting from c).
A method according to any preceding claim, in which when
- i) the monitoring of the level of water in the boiler shows an increase in level but at a rate of increase below a predetermined level.
- ii) the monitoring of the pressure in the boiler shows an increase in pressure but at a rate of increase below a predetermined level, and
- iii) the monitoring of the firing rate of the burner shows that the firing rate is reducing
- the controlling of the flow rate of water into the boiler is such that it does reduce the rate of flow into the boiler.
A method according to any preceding claim, in which input and output signals relating to all the monitoring and controlling steps are passed into or transmitted from a common control unit that also controls the operation of the burner.
A method according to any preceding claim, in which the step of monitoring the level of water in the boiler includes the steps of providing a pair of capacitance probe assemblies mounted in the boiler with each of the probes extending through a range of water levels, the probes being arranged such that the capacitance of each probe varies according to the level of the water, and of measuring the capacitance of each probe, comparing the capacitances to one another to check that they match and using the measurement of the capacitance as an indication of the water level.
A method according to any preceding claim, further including the step of assessing in a control unit the mass flow of steam from the boiler by processing of input signals including ones enabling assessments to be made of:
- a) the heat generated by combustion in the burner
- b) the temperature and pressure of the steam generated by the boiler
- c) the heat dissipated other than in the steam.
A method of monitoring the level of water in a pressurised steam boiler, the method including the steps of providing a pair of capacitance probe assemblies mounted in the boiler with each of the probes extending through a range of water levels, the probes being arranged such that the capacitance of each probe varies according to the level of the water, and of measuring the capacitance of each probe, comparing the capacitances to one another to check that they match and using the measurement of the capacitance as an indication of the water level.
A method of assessing in a control unit the mass flow of steam from a pressurised steam boiler by processing input signals including ones enabling assessments to be made of:
- a) the heat generated by combustion in the burner
- b) the temperature and pressure of the steam generated by the boiler
- c) the heat dissipated other than in the steam.
A method of monitoring turbulence in a pressurised steam boiler, the method including the step of providing a water level monitoring device capable of monitoring a multiplicity of water levels extending over a range, monitoring the water level at a plurality of different times, and comparing the results of monitoring to assess whether or not the water is turbulent.
A pressurised steam boiler including:
- a boiler housing for containing water in the boiler,
- a burner for heating water in the boiler and converting the water into steam,
- a water level detector for monitoring the level of water in the boiler,
- a pressure detector for detecting the pressure of steam in the boiler,
- a firing rate detector for detecting the firing rate of the burner, and
- a control unit which receives input signals from the water level detector, the pressure detector and the firing rate detector and is operative to control the flow rate of water into the boiler in dependence upon said input signals.
A pressurised steam boiler including:
- a boiler housing for containing water in the boiler, and
- a water level detector for monitoring the level of water in the boiler, the water level detector comprising a pair of capacitance probe assemblies mounted in the boiler housing with each of the probes extending through a range of water levels, the probes being arranged such that the capacitance of each probe varies according to the level of water, and a control and processing system for measuring the capacitance of each probe, comparing the capacitances and providing an output signal indicative of water level based on the capacitance measurements.
A pressurised steam boiler including:
- a boiler housing for containing water in the boiler,
- a burner for heating water in the boiler and converting the water into steam,
- a pressure detector for detecting the pressure of steam in the boiler,
- a temperature detector for detecting the temperature of steam in the boiler,
- a fuel flow detector for measuring the flow rate of fuel into the burner,
- a further temperature detector for detecting the temperature of the exhaust gases,
- a control unit for receiving and processing input signals from all of said detectors and for assessing indirectly the mass flow of steam from the boiler.
A pressurised steam boiler including:
- a boiler housing for containing water in the boiler,
- a water level monitoring device capable of monitoring a multiplicity of water levels extending over a range, and
- a control unit for storing results of monitoring the water level at a plurality of different times and for comparing the results to assess whether or not the water is turbulent.
Dependencies are inferred from the claim text.