Bag dust removal leak detector Model: HDLBJ-7
Principle:
In flowing powder, electrostatic charges are generated due to friction and collision between particles, particles and pipe walls, and particles and cloth bags, forming an electrostatic field. The changes in this electrostatic field reflect the changes in dust content. The leak detector judges whether the bag dust removal system is operating normally by measuring the changes in the electrostatic field. When the bag is broken, the dust content of the gas-solid two-phase flow in the pipeline increases, and the intensity of the electrostatic field also increases.
This set of device primarily consists of three components: ① sensor (signal acquisition part), ② transmitter (signal processing part), and ③ signal transmission. Its principle block diagram is illustrated in Figure 1, and the display functions and buttons at each point are detailed in Panel Layout Figure 2.
The function of the sensor is to convert the electrostatic field strength formed during the powder flow process into an electrical signal through electrostatic induction, and transmit this signal to the transmitter via a cable.
The transmitter consists of a multi-channel board, whose output is an analog current and sound-light display that varies with the measured powder content. The new-type meter outputs a 4-20mA current signal, an alarm switch value, or outputs data signals through an RS485 interface. During normal operation (i.e., no broken bags, and powder content within acceptable limits), the HDLBJ-7 meter displays green lights for each channel and a red light is off, while outputting an analog current value. The current values output by each channel are measured through automatic inspection and manual point selection by a microcontroller. The device can operate in either "automatic inspection" or "manual point selection" mode as needed. The "box selection" button functions as both a switch for switching between "automatic" and "manual" modes and, in manual mode, as a toggle switch for box measurements.
Features:
With the improvement of industrial automation and the increasing emphasis on environmental protection, the monitoring of industrial dust has become increasingly stringent. The bag dust removal online monitoring instrument we have developed is an effective tool for online monitoring of whether the bags of bag filters are damaged and for online monitoring of dust content in various boxes. It can accurately and timely detect and prevent the emission of harmful dust and reduce the loss of useful powder, achieving the goal of protecting the safe operation of main equipment and reducing economic losses of products. It can also instantly reflect the operating status of each bag dust removal box.
This instrument can be widely used for leak detection in bag dust removal systems in metallurgy, electric power, chemical industry, pharmaceuticals, food processing, building materials, wood processing, and other industries. For example, when used for leak detection in the dry ash removal system of large thermal power generating units, it can prevent wear on the negative pressure fan caused by the rupture of the bag filters in the bag dust collectors. It can also prevent excessive dust emissions and environmental pollution caused by damaged bags after the separation of wind and powder in the positive pressure ash removal process. Especially in the process of metallurgical ironmaking, leak detection of blast furnace gas bag dust collectors, which are highly toxic (CO content close to 30%) and operate under positive pressure, has special practical value. Over the past ten years, from small furnaces to large furnaces (2500M³), from one trial installation to multiple installations (some manufacturers have installed multiple units), the instrument has been tested in production practices by multiple manufacturers across the country. It is sensitive, reliable, requires minimal maintenance, and is highly practical. It can meet production needs, replace manual leak detection, and display concentration in real time. It is the first of its kind in China, with leading technology in the country, and has significant economic, social, and environmental benefits, making it highly valuable for promotion and use.
The HDLBJ-7 bag filter leak detector has two major series. One series features an instrument that can simultaneously monitor the operating conditions of 8, 10, or 12 bag filter boxes online. This series of instruments includes computer patrol inspection, over-limit light display, audible alarm, 4-20mA analog current indication, and switch output. The other series not only monitors the operating conditions of the filter boxes online but also comes equipped with a main duct concentration meter, allowing for real-time online monitoring of dust concentration in the main duct. This series of instruments displays the dust concentration values of each bag filter box and the main duct on a liquid crystal display, and features dust over-limit alarms and sensor fault alarms. It also outputs 4-20mA current, RS485 interface, and switch output (passive)
The HDLBJ-7 series of instruments boasts a simple structure, high sensitivity, accurate and timely signal transmission, safe and reliable operation, convenient installation, minimal maintenance, and a wide range of applications (various types of dust, positive and negative pressure systems, and a wide range of dust particle sizes). It is indeed a practical dust online monitoring device for various industrial enterprises.
Technical parameters:
★Measurement range: dust concentration: 0-1000mg/m3.
★The measured pipe diameter ranges from 0.1 to 3 meters.
★Measured particle size: 1-80μm
★Allowable temperature for sensor measuring point: <260℃.
★Pressure range of sensor measuring point: 2.0 MPa.
★Insertion depth of sensor: 300mm (the total tube length is 1200mm).
★Operating temperature range of the instrument: -30 to 80℃.
★The dimensions of the transmitter chassis in width, height, and thickness are: 430×530×200mm