SANAA
UREMBO NA USTAWI
UJANJA
UTAMADUNI NA HISTORIA
BURUDANI
MAZINGIRA
CHAKULA NA VINYWAJI
UHANDISI WA KINYUME
SAYANSI
MICHEZO
TEKNOLOJIA
VAZI
The Economiser: The Heat Still Going Up the Chimney
Even a good boiler sends its flue gas up the chimney hot. Edward Green's economiser of 1845 put a bank of cast-iron tubes in the flue and ran the cold feed water through them on its way to the boiler, so the gas that was leaving anyway warmed the water that was arriving anyway. His tubes carried mechanical scrapers that travelled up and down them to keep the soot off, because a sooted tube is an insulated tube.
The same idea is in every modern condensing boiler, which cools its flue gas until the water vapour in it condenses and gives up its latent heat too.
This rung works out how much heat the stack carries away, measures a real flue, and finds the dew point below which an economiser starts to run wet.
Kati
About 3 hours
Maagizo
1
1
Stack loss and the dew point
Stack loss and the dew point
Inapakia daftari la Jupyter…
2
2
Measure a real flue
Measure a real flue
Find a flue you are allowed to measure: a wood stove's stove pipe, a workshop heater, the test port of a gas boiler (ask whoever services it). Strap the thermocouple tip against the flue pipe with a hose clip a metre above the appliance, and log it every minute from a cold start to steady running. Measure the room air too.
The pipe surface reads lower than the gas inside, so this is a floor under the true stack temperature. Put it into the notebook's table: even the floor usually shows several per cent of the fuel leaving as heat.
Never block, puncture or restrict a working flue. Flue gas contains carbon monoxide.
Zana zinazohitajika:
Themokapo yenye kionyeshi
Kipima-joto cha jikoni
Saa ya kupima muda
Spana inayoweza kurekebishwa
Glavu za Kazi za Ngozi
Mchanganyiko wa vibano vya mpira3
3
The feed water gets the heat, not the room
The feed water gets the heat, not the room
An economiser is a counterflow heat exchanger (rung 5 of this batch explains why counterflow): the coldest water meets the coolest gas at the chimney end, and the warmest water meets the hottest gas at the boiler end. That is how it cools the gas as far as it does.
It sits between the feed pump and the boiler, so it runs at boiler pressure; a check valve and a safety valve protect it. Green's tubes were cast iron, with scraper gear travelling up and down them to deal with the soot.
4
4
The flue runs hotter than it should: find out why
The flue runs hotter than it should: find out why
A rising stack temperature is fuel going up the chimney. The usual causes, in order.
Flow
Loading...
5
5
History and context
History and context
**Edward Green of Wakefield, 1845** — the fuel economiser, cast-iron vertical tubes in the flue with mechanical scrapers. It spread through the mills of northern England and the name stuck to the whole class of flue-gas feed-water heaters. No patent number is asserted here.
Its descendants are the economiser bank in every power-station boiler, the air preheater (rung 7 of this batch), and the condensing domestic boiler.
**Honest limits.** An economiser adds resistance to the flue, so a natural-draught chimney may need a fan. Cooled below the dew point it condenses, and with sulphur fuels the condensate is acid. And a sooted or scaled economiser saves nothing.
Zana Zinazohitajika
6- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
- Kishikilia Nafasi
Blueprint zinazohusiana
Blueprint hizi zinashiriki maarifa — mbinu, vifaa au kanuni
CC0 Umma Wote
Mchoro huu umetolewa chini ya CC0. Uko huru kunakili, kubadilisha, kusambaza, na kutumia kazi hii kwa madhumuni yoyote, bila kuomba ruhusa.
Saidia Mtengenezaji kwa kununua bidhaa kupitia Mchoro wao ambapo wanapata Kamisheni ya Mtengenezaji iliyowekwa na Wachuuzi, au unda marudio mapya ya Mchoro huu na uiunganishe kama kiungo katika Mchoro wako kuchangia mapato.