Boiler system

Patent metadata

Field	Value
Publication number	US-10030866-B2
Application number	US-201414912524-A
Country	US
Kind code	B2
Filing date	Aug 7, 2014
Priority date	Aug 19, 2013
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A boiler system equipped with a boiler group mixedly provided with a step value control boiler and a proportional control boiler. A boiler number control device is configured to control the number of boilers in the boiler group, and includes an output controller configured to control a combustion state of the boiler group so as to cause the proportional control boiler to output steam equivalent to a required steam flow according to a required load, and an output switcher configured to switch, under a condition that a steam flow outputted from the proportional control boiler reaches a predetermined steam flow exceeding a steam flow at a possible combustion point of the step value control boiler, output of the steam flow at the combustion point from the proportional control boiler to the step value control boiler.

First claim

The invention claimed is:

1. A boiler system comprising:
a boiler group including a step value control boiler configured to combust at a plurality of stepwise combustion points and a proportional control boiler configured to combust at a continuously changed combustion rate; and
a controller configured to control a combustion state of the boiler group in accordance with a required load, wherein

the controller includes:
an output controller configured to control the combustion state of the boiler group to cause the proportional control boiler to output steam equivalent to a required steam flow according to the required load; and
an output switcher configured to switch, under a condition that a steam flow outputted from the proportional control boiler reaches a predetermined steam flow exceeding a steam flow at a possible combustion point of the step value control boiler, output of the steam flow at the combustion point from the proportional control boiler to the step value control boiler;
wherein the proportional control boiler is configured to have an ecological operation zone in which boiler efficiency of the proportional control boiler is higher than a predetermined threshold, and
wherein the predetermined steam flow is more than the steam flow at the combustion point by a steam flow corresponding to a lower limit value within the ecological operation zone.

2. The boiler system according to claim 1 , wherein, even when the step value control boiler combusts at a combustion point with maximum efficiency and a steam flow outputted from the proportional control boiler reaches the predetermined steam flow, the output switcher keeps output from the proportional control boiler.

3. A boiler system comprising:
a boiler group including a step value control boiler configured to combust at a plurality of stepwise combustion points and a proportional control boiler configured to combust at a continuously changed combustion rate; and
a controller configured to control a combustion state of the boiler group in accordance with a required load,
wherein the controller includes:
an output controller configured to control the combustion state of the boiler group to cause the proportional control boiler to output steam equivalent to a required steam flow according to the required load; and
an output switcher configured to switch, under a condition that a steam flow outputted from the proportional control boiler reaches a predetermined steam flow exceeding a steam flow at a possible combustion point of the step value control boiler, output of the steam flow at the combustion point from the proportional control boiler to the step value control boiler,
wherein the step value control boiler is configured to have a combustion point with maximum efficiency in the plurality of stepwise combustion points, and
wherein, even when the step value control boiler combusts at the combustion point with maximum efficiency and a steam flow outputted from the proportional control boiler reaches the predetermined steam flow, the output switcher keeps output from the proportional control boiler.

4. A method for controlling a boiler system which comprises a boiler group including a step value control boiler configured to combust at a plurality of stepwise combustion points and a proportional control boiler configured to combust at a continuously changed combustion rate, and a controller configured to control a combustion state of the boiler group in accordance with a required load,
the method comprising:
controlling the combustion state of the boiler group to cause the proportional control boiler to output steam equivalent to a required steam flow according to the required load; and
switching, under a condition that a steam flow outputted from the proportional control boiler reaches a predetermined steam flow exceeding a steam flow at a possible combustion point of the step value control boiler, output of the steam flow at the combustion point from the proportional control boiler to the step value control boiler,
wherein the proportional control boiler is configured to have an ecological operation zone in which boiler efficiency of the proportional control boiler is higher than a predetermined threshold, and
wherein the predetermined steam flow is more than the steam flow at the combustion point by a steam flow corresponding to a lower limit value within the ecological operation zone.

Assignees

• Miura Kogyo Kk

Inventors

• Hyodo Yasuhiro

Classifications

• F22B35/008 Primary

  Control systems for two or more steam generators (automatic water-feed control for a number of steam boilers designed for different ranges of temperature and pressure F22D5/36) · CPC title