Steam Chemical Injection Control Using Circulation Detection

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Solution Overview

Problem

Existing chemical injection methods for steam systems are inefficient and costly, often leading to excessive chemical addition and odor problems due to the lack of steam flow meters and interlock mechanisms, causing issues during equipment stoppages.

Innovation Solution

A chemical injection method that uses pressure or temperature sensors, steam traps, and anti-siphon check valves to control the injection of water treatment chemicals based on steam circulation status, ensuring chemicals are only added when steam is present, thereby preventing excessive addition during equipment stoppages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If corrosion inhibitors are directly added to the steam system without steam flow meters and interlock mechanisms, then the chemical injection is simple and低成本, but excessive chemical addition occurs during equipment stoppages causing odor problems

Engineering Contradiction:
Improvechemical injection system simplicityVSAvoidodor problems from excessive chemical addition
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a steam circulation detection mechanism that provides feedback control for chemical injection. The detection part (steam flow meter, pressure sensor, temperature sensor, or steam trap) monitors steam circulation status and feeds this information back to the chemical injection control, which adjusts or stops chemical injection when steam circulation is absent, preventing excessive chemical addition during equipment stoppages

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses existing steam system components (steam flow meters, pressure sensors, temperature sensors, or steam traps) to detect steam circulation status, allowing the system to self-regulate chemical injection without requiring complex external control systems or expensive steam flow meters in all locations

Inventive Principle:
Principle #25Self-service

2Reliability

If corrosion inhibitors are added to boiler feedwater or condensate system, then corrosion prevention is achieved, but a portion of the chemical remains in boiler water requiring excessive chemical addition

Engineering Contradiction:
Improvecorrosion prevention effectivenessVSAvoidexcessive chemical addition
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the chemical injection point from the boiler feedwater or condensate system and relocates it directly to the steam system. This ensures chemicals are added only where steam is present and circulated, preventing chemical accumulation in boiler water and eliminating the need for excessive chemical addition while maintaining corrosion prevention effectiveness

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If chemical injection pump operates without steam circulation detection, then the injection system is simple to operate, but chemical diffusion at high concentration occurs when steam is supplied again after stoppage

Engineering Contradiction:
Improvechemical injection operation simplicityVSAvoidchemical concentration control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The steam circulation detection status provides real-time feedback control for the chemical injection pump operation. The pump operates only when steam circulation is detected and stops when steam circulation is absent, preventing chemical accumulation and high concentration diffusion upon restart while maintaining simple operation through automatic control

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Prevents excessive chemical addition and odor issues by controlling chemical injection based on steam circulation detection, optimizing chemical use and reducing costs.

Implementation Method 1

a pressure sensor, a temperature sensor, or a steam trap as a steam circulation detection part provided in the steam system

Methodology Applied
Scientific EffectPressure detection:

Implementation Method 2

a pressure sensor, a temperature sensor, or a steam trap as a steam circulation detection part provided in the steam system

Methodology Applied
Scientific EffectTemperature detection:

Implementation Method 3

a steam trap and a steam circulation detection sensor of the steam trap

Methodology Applied
Scientific EffectPhase change detection: Phase Change

Implementation Method 4

a chemical injection pump for injecting the water treatment chemicals into the steam system

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 5

the water treatment chemicals are injected into the steam system by spraying with a spray nozzle

Methodology Applied
Scientific EffectSpray: Spray

Implementation Method 6

an anti-siphon check valve is provided in a chemical injection piping

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4678977A1Method for feeding chemical to steam system
Publication Date: 2026.01.14 KURITA WATER INDUSTRIES LTD
  • EP4678977A1 patent drawingFigure 1
  • EP4678977A1 patent drawingFigure 2
  • EP4678977A1 patent drawingFigure 3

AI summary

Provided is a chemical injection method for steam system for controlling injection of water treatment chemicals into a steam system, in which, in response to a pressure sensor, a temperature sensor, or a steam trap as a steam circulation detection part provided in the steam system; a chemical injection pump for injecting the water treatment chemicals into the steam system; and a steam circulation detection status of the steam circulation detection part, the injection of the water treatment chemicals by the chemical injection pump is controlled.