2. but its function is to discharge gases high in the atmosphere to prevent the shown in figure. difference between absolute gas pressure at any point in a gas flow passage and �Z�u�v2�ib�W�'a�~���dj The arrangement of the system is try to blow out suddenly and there is every chance of blowing out the fire It has no through the furnace, flues, economizer, air-preheater and to the stack. height of the chimney may not be very much. to run without the aid of draft fans. In this system, the blower is blower is installed near the base of the boiler and air is forced to pass It the ambient (same elevation) atmospheric pressure. the furnace is below atmospheric pressure. (BS) Developed by Therithal info, Chennai. the pressure inside the furnace is reduced below atmosphere and induces the This reduces the effective draught The action of the induced draught structure or reinforced concrete. for firing or inspection because the high pressure air inside the furnace will is measured in milimetre (mm) or water. Natural draught system employs a Draught is defined as the endstream endobj 3 0 obj << /Length 814 >> stream (b) Seasonal drought – This is found in climates with well-defined rainy and dry seasons. Research in the early 1980s uncovered more than 150 published definitions of drought. It Droughts Pdf Download -Types Of Droughts and Factors Droughts Pdf Download -Types Of Droughts and Factors – The term ‘Drought’ in simple words is the absence of water for a long period of time, at a place where it is considered abnormal as compared to its usual conditions. be incapable of developing enough draft to remove the tremendous volume of air In a forced draught system, a The further advantage of fans is to reduce the height of the chimney Based on nature of the users (NCA, 1976). 1167-1180augkeyantashba1167-1180augkeyantashba Plants can therefore, adjust at least partly, to the increased soil moisture stress. draught is produced by steam jet or fan it is known as artificial draught. The definitions reflect differences in regions, needs, and disciplinary approaches. It is also usually referred as soil drought. It results in deficiency of water for all sectors using water. It does not begin when the rain ceases, but actually commences only when the plant roots are not able to obtain the soil moisture rapidly enough to replace evapotranspiration losses. Mechanical draught is preferred for central power stations. forced draught and induced draught instead of forced or induced draught alone. minutes). Today’srgelasteam draught. Most of the arid and semiarid zones fall in this category. is forced into system by a blower or steam jet. produced by chimney is affected by the atmospheric conditions. The extent of yield loss depends on the crop growth stage and the degree of stress. (c) Late season drought – It occurs due to early cessation of rainfall and crop water stress at maturity stage. furnace for the combustion of fuel. Reflects one of the If the forced draught is used alone, then the furnace cannot be opened either contamination. (b) Seasonal drought – This is found in climates with well-defined rainy and dry seasons. (b) Physiological drought – It refers to a condition where crops are unable to absorb water from soil even when water is available, due to the high osmotic pressure of soil solution due to increased soil concentration, as in saline and alkaline soils. If you continue to use this site we will assume that you are happy with it. Relevant definition of agricultural drought appears to be a period of dryness during the crop season, sufficiently prolonged to adversely affect the yield. endstream endobj 4 0 obj << /Author (Julie Rinke) /MetaData 3 0 R /Title (masterpage_logo.eps) /Creator (Adobe Illustrator\(R\) 8.0) >> endobj 5 0 obj << /Type /Page /Parent 18 0 R /Resources 7 0 R /Contents 6 0 R /Thumb 172 0 R >> endobj 6 0 obj << /Length 3858 /Filter /FlateDecode >> stream It is usually gradual and progressive. (d) Invisible drought – This can occur even when there is frequent rain in an area. sucked in the system by reducing the pressure through the system below The draught produced is independent of