Table of Contents
- 1 How do you control drum level?
- 2 What is a drum level?
- 3 How do you maintain steam pressure in a boiler?
- 4 What is level control system?
- 5 Which type of control is used in boiler drum level control?
- 6 How is a liquid level in a boiler drum measured?
- 7 What’s the best way to protect a drum?
- 8 What happens if the drum level is too low?
How do you control drum level?
Boiler Drum Level Control
- Disturbances in drum level are caused by fluctuations in main steam flow.
- Figure 1 shows a typical drum level controller, which measures the drum level (1), main steam flow (2), and feedwater flow (3) and manipulates the feedwater control valve to regulate the drum level.
What is a drum level?
The purpose of the drum level controller is to bring the drum up to level at boiler start-up and maintain the level at constant steam load. A dramatic decrease in this level may uncover boiler tubes, allowing them to become overheated and damaged.
Why do you think boiler drum level measurement is important?
Boiler drum level is a critical measurement necessary to maintain efficient, reliable, and safe operations. If the boiler steam/water interface level is too low, it can lead to boiler tube damage due to overheating.
What is boiler drum level?
Drum Level Control Systems are used extensively throughout the process industries and the Utilities to control the level of boiling water contained in boiler drums on process plant and help provide a constant supply of steam. If the level is too high, flooding of steam purification equipment can occur.
How do you maintain steam pressure in a boiler?
The operator control should be set about 5–10 PSI above the actual steam pressure you want to maintain in the boiler. This allows the boiler to reach low fire and if steam pressure keeps rising, it will shut down the boiler. The boiler will restart when the pressure drops below the differential set on the operator.
What is level control system?
Liquid Level Control System is a system specifically designed to control the level of fluid in tanks. The main aim possessed by these systems is to control the rate with which the pump delivers fluid to the tank and so it can reach the desired level inside the tank.
How do you calibrate a drum level transmitter on a boiler?
To perform the calibration, use a table of thermodynamic properties of steam and the following steps:
- Determine hmin and hmax.
- Using the saturated steam tables, find the values of and at the drum operating pressure.
- For this example assume:
- Solve the equation:
Why is my boiler drum level negative?
If we use 0 to 50 range and system indicates that drum level is 0% ,its mean drum is empty. We avoid empty drum level. Also negative range tells us reference of water and steam in boiler. Thats why we use negative range in boiler.
Which type of control is used in boiler drum level control?
To control both drum level and feedwater flow rate, cascade control is used. The drum level controller becomes the primary controller and its output drives the set point of the feedwater flow controller, the secondary control loop.
How is a liquid level in a boiler drum measured?
They are measured from the bottom tap of the steam drum. 2. Using the saturated steam tables, find the values of and at the drum operating pressure. Use the value for compressed water in the reference (wet) leg at the expected ambient temperature and the drum operating pressure.
How do you maintain a boiler?
How to Effectively Maintain a Boiler System
- Examine the Vent and Chimney.
- Check the Heat Exchanger.
- Flush out the Boiler.
- Lubricate the Circulating Pump.
- Get Help from an Expert.
- Adjust the Boiler to Operate Efficiently.
What is the function of drum level control?
Basic Function of Drum level control: A boiler is used to heat water to steam. To accomplish this a series of tubes are placed in the boiler to confine the water and provide a large heat transfer surface for interfacing with the hot gases of combustion. The water in these tubes is turned to steam.
What’s the best way to protect a drum?
When it is damp or humid you can protect the tone by storing your drum in wool, cotton or one of our custom drum bags. When it is cold, warm it gradually.
What happens if the drum level is too low?
If the level is too low, reduction in efficiency of the treatment and recirculation function. Pressure can also build to dangerous levels. A drum level control system tightly controls the level whatever the disturbances, level change, increase/ decrease of steam demand, feedwater flow variations.
When to use a single element drum level strategy?
The single-element drum level strategy is only effective for smaller boilers with relatively steady demands and slow to very moderate load changes. The level of the tank is measured and the variable is added to the control system. The control action produced is based only on the level of water in the boiler.