IR-S Infrared Flame Detector
Overview
Due to the diversification of boiler fuels and low NOx (nitrogen oxide) operation in recent years, it has become difficult to monitor burner flames using conventional ultraviolet and infrared detection methods.
To adapt to this changing business environment, Mitsubishi Power has improved upon conventional IR flame detectors and commercialized the IR-S Infrared Flame Detector, a new type of flame detector with excellent detection reliability, maintainability and cost performance.
An IR-S type infrared flame detector uses a light guide (optical fiber) to guide the light from the flame to an infrared sensor (semiconductor device). The "average value" and "variance" of the intensity of the infrared light are detected so that the infrared light intensity from the burner flame and that from the heated furnace wall are differentiated. Consequently, the variance of the flame in the burned zone in the burner is detected.
This results in dramatic improvements to detection sensitivity and dynamic range in low-luminance conditions, and allows the detector to support various fuels including gas, fuel oil and coal.
The IR-S Infrared Flame Detector employs a newly-developed sensor circuit to achieve reliable boiler flame monitoring.
If you replace a conventional flame detector with this new type, the pre-existing equipment can be reused.
| Equipment Name | Existing Methods of Flame Detection | |
|---|---|---|
| UV Type | IR Type | |
| Sensor Unit | Replaced | Replaced |
| Flame Detector Panel | Replaced | Replaced |
| Sensor Cable | Reused | Replaced |
| Guide Pipe | Reused | Reused |
| Cooling-air Piping | Reused | Reused |
| Cooling Fan | Reused | Reused |
Features
High Sensitivity Design
The newly designed sensor circuit enables stable detection of the burner flame. The flame is detected through the unlit zone.
Extended Detection Range
The sensor has 100 times the dynamic range of a conventional product and allows stable detection from slow combustion to a high intensity flame. No sensitivity adjustment is required for the sensor at the site.
Maintenance Free
A ball lens is used to eliminate the need to clean the sensor window.
Long-life Sensor
Because a long-life infrared semiconductor sensor element is used, periodic replacement is not necessary.
Decreasing the Number of Panels
The detector unit is compact with a space-saving design which allows one panel to incorporate 40 corners.
Reuse of Existing Boiler Facilities
When you replace a flame detector, work is not necessary for the boiler itself.
Reuse of Cable
Changing the cable between the sensor and the panel is not necessary. (When the existing system uses UV-type detection)
System Configuration
Flame Detector Panel
Flame Detector Panel
Flame Detector Unit
Flame Detector Main Unit
Flame Detector Main Unit
Cross Sectional View of Sensor Head
For Fuel Oil Burner
The following example applies to a fuel oil burner.
Specifications
Sensor Unit
The specifications of the sensor unit are as follows.
| Series | Explosion-proof (Exd II BT4), waterproof | |
|---|---|---|
| Dimensions | Entire Length | Optional |
| Guide Pipe | 50A (40A) | |
| Detection Wavelength | 500 - 1,100nm | |
| Allowable Temperature | Detector Head Component | Not exceeding 200℃ |
|---|---|---|
| Cooling Air | Temperature | Not exceeding 60℃ |
| Air Pressure | In-furnace pressure +1.5kPa or greater | |
| Air Flow | At least 1.0Nm3/min per sensor (fan capacity should be designed at 1.5Nm3/min per sensor to account for when withdrawn inspection takes place) |
Flame Detector Panel
The specifications of the flame detector panel are as follows.
| Series | Closed indoor self-standing type, with access hatches on front and back | |
|---|---|---|
| Dimensions | 2,300mm (H) ×810mm (W) ×800mm (D) | |
| Configuration |
|
|
| Output Signals | Flame on | 1a |
| Low luminance level | 1a | |
| Power loss | 1b | |
| Contact capacity | AC/DC 48V, 1.25A | |
| Ambient Temperature | 0 to 50℃ | |