41 - Boilers Flashcards
What are the defining factors of a water tube boiler?
A water tube boiler is a type of boiler that uses water that circulates through tubes that are surrounded by hot combustion gases.
What are the defining factors of a fire tube boiler?
A firetube boiler, uses hot combustion gases that travel through tubes, which are surrounded by water.
What are the defining factors of a low pressure boiler?
Low-pressure boilers operate at a lower pressure and reach lower temperatures than high-pressure steam boilers. Water in low-pressure boilers is not heated beyond 250ºF, and the steam pressure does not exceed 15 psi
What are the defining factors of a high pressure boiler?
High-pressure steam boilers create steam at above 15 psi. In practice, industrial high-pressure boilers often operate at hundreds of psi. They also operate at considerably higher temperatures than low-pressure boilers.
What are the defining factors of a hot water boiler?
A hot water boiler is a complex heating appliance that heats water to create hot water for heating and other uses.
What are the defining factors of a steam boiler?
A steam boiler is a pressurized vessel that transfers heat to water to produce steam for a variety of applications.
How can a pressure relief valve on a boiler be identified?
A boiler’s pressure relief valve (PRV) is usually located on the side of the boiler near the water level and attached to a pipe that extends to the floor or drain.
What is a pressure relief valve on a boiler?
PRVs, also sometimes known as safety release valves, are in place to prevent a buildup of pressure. The valve opens to release pressure when the level becomes too high, and closes again when the pressure has dropped to within a safe range.
What is a low water cut off on a boiler?
Low water cutoff switches are generally 2-6 inches below the NOWL. The LWCO uses an electric conductivity probe or a float to detect the water level inside the boiler. When water drops below this level, LWCOs prevent the burner from firing.
How can a high temperature cutoff on a boiler be identified?
What is a high temperature cut off on a boiler?
What is a high/low gas pressure switch on a boiler?
How can a high/low gas pressure switch on a boiler be identified?
What are boiler tubes?
In water tube boilers, the metal tubes situated inside the boiler contain water and are externally heated. In firetube boilers, heated gas passes through one or more tubes, heating water surrounding the tubes.
When and why should boiler tubes be replaced?
How are boiler tubes replaced?
What are boiler burners?
The burner provides heat to the boiler by combusting fuel and oxygen. Fuel sources include natural gas, low-pressure propane, No. 2 oil, coal and other fuels.
When and why should boiler burners be replaced?
How are boiler burners replaced?
What is boiler blow down?
Boiler blowdown is the removal of water from a boiler. Its purpose is to control boiler water parameters within prescribed limits to minimize scale, corrosion, carryover, and other specific problems. Blowdown is also used to remove suspended solids present in the system.
How can boilers be blown down safely?
1: Open the quick-opening valve (closest to the boiler) first
2: Open the slow-opening valve last
3: Blowdown the boiler for the required amount of time, per your water management consultant, by opening and then closing the slow opening valve. Important: pay close attention to the water level in the gauge glass. Certain loads may require several blowdown cycles of shot duration to maintain proper water level in the boiler.
4: Close the slow-opening valve first
5: Close the quick opening valve last (the valve closest to the boiler – front and rear of boiler) * Repeat steps 1- 5 for both the front quick opening valve and then the rear quick opening valve
6: Open the slow opening valve, again, to drain the line between the quick and slow opening valve
7: Close the slow opening valve again, and double-check for tight shutoff after the valve has cooled-off
What is a boiler outdoor reset control?
An outdoor reset control consists of three parts: an outdoor sensor, an element within the boiler’s main control, and a wire running between the two. The outdoor reset control “tells” the boiler what the actual, real-time outdoor temperature is. This allows the boiler to respond to the outdoor temperature by raising or lowering the boiler’s supply water temperature being delivered to your heating system.
What is a boiler turndown ratio?
A boiler turndown ratio refers to the ratio between a boiler’s highest fire setting (maximum output) and lowest fire setting (minimum output).
Turndown ratios vary depending on the boiler. For example, if your boiler has a 3:1 turndown ratio, that means that at its lowest fire setting you will be operating at 33% of the boiler’s full capacity. If you have a 10:1 turndown, that means that at its lowest setting, your boiler is operating at 10% of its full capacity.
What is boiler water treatment?
Water used by the boilers needs to be treated before entering the boiler to prolong the life of the boiler. Water softeners and Reverse Osmosis systems help to prepare the water by removing dissolved solids like calcium and magnesium to reduce the potential for scale build-up within the boiler. Feedwater tanks are also a part of the water treatment as they use heat to reduce the number of dissolved gases within the water that can contribute to oxidation and corrosion within the boiler.
What are boiler chemical monitoring systems?
The carefully controlled addition of chemicals can enhance a boiler’s operations. Chemical monitoring systems precisely monitor chemical levels and provide ongoing analysis.
How does a reverse osmosis system work in a boiler?
Reverse Osmosis works by using a high-pressure pump to increase the pressure on the raw water side of the RO and force the water across the semi-permeable RO membrane, leaving almost all (around 95% to 99%) of dissolved impurities behind in the reject stream.
What is a boiler feedwater tank?
The feedwater tank is a collection tank that supplies the water used by the boiler to create steam. The feedwater tank is where the treated water is collected and then pumped into the boiler. Boiler chemicals that remove oxygen and protect the metals within the boiler are injected and mixed within the feedwater tank. Facilities with condensate return lines can collect condensate water from steam that drops below the boiler point and fed back into the system to recapture the treated water.
What is a boiler heat exchanger?
A heat exchanger transfers heat from one substance to another without those substances directly interacting. In a boiler, the hot gas’ heat is transferred to the water via a heat exchanger.
What is a boiler deaerator tank?
Deaerators are pressurized feedwater tanks that use pressure and heat to remove oxygen and other dissolved gases (notably, carbon dioxide) from the water fed into the boiler. Dissolved oxygen and carbon dioxide could otherwise cause serious corrosion to the boiler.
What is a boiler economizer?
An economizer is a heat exchange mechanism that transfers heat energy otherwise lost in exhaust gasses and uses that energy to heat the water entering the boiler. Consequently, less additional energy is required to heat the incoming water, making the boiler more efficient.
What is a boiler pressure vessel?
A pressure vessel contains gases or liquids at high temperatures, usually under high pressure. In a boiler, the pressure vessel is constructed from a high-strength material, often steel.
