Water gauge

FIG. 14-114 Collection efficiency of Karbate bne separator, based on particles with a specific gravity of 1.0 suspended in atmospberic air with a pressure drop of 2.5 cm water gauge. (Union Caihide Corporation Cat. Sec. S-6.900, 1960.)... 

Cyclone Separators Cyclone separators are described in Chapter 7. Typically used to remove particulate from a gas stream, the gas enters tangentially at the top of a cylinder and is forced downward into a spiral motion. The particles exit the bottom while the gas turns upward into the vortex and leaves through the top of the unit. Pressure drops through cyclones are usually from 13 to 17 mm water gauge. Although seldom adequate by themselves, cyclone separators are often an effective first step in pollution control. 

Bee.iusa the nitrogen pressure was unreliable, it was difficult to maintain a pressure of 0.5 inch water gauge in the metal cabinet. Workers complained that the safety switch kept isolating the electricity supply, so an electrician reduced the setpoint first to 0.25-inch and then to zero, thus effeciocly bypassing the switch. The setpoint could not be seen unless the cover of the switch was removed and the electrician told no one what he had done. The workers though I lie wa,s a good electrician who had prevented spurious trips. Solvent and air leaked into the cabinet, as ilready described, and the next time the electricity supply was switched there was an explosion. 

Manometer pressure The pressure recorded on a manometer, measured in Pa or mm water gauge. 

Very small gauge pressures are quoted in inches water gauge, as this gives a picture. 

Pressure drop through wire mesh units is usually very low, in the order of 1-inch water gauge for a 4-inch or flinch thick pad. For most pressure applications this is negligible. If solids are present in the particle stream, then... 

Direct expansion cooling Temperature difference Air changes (room volumes) per hour Air-handling unit Static water gauge... 

Section 38 of the Factories Act 1961 defines a steam boiler as a any closed vessel in which for any purpose steam is generated under pressure greater than atmospheric pressure . Economizers used to heat water being fed to such a vessel and superheater for heating steam are also included. Every boiler must be fitted with the recommended safety measures (e.g. safety valve, stop valve, water gauge, low-water alarms, pressure gages, etc.). 

What size of orifice would give a pressure difference of 0.3 m water gauge for the flow of a petroleum product of specific gravity 0.9 at 0.05 m3/s in a 150 mm diameter pipe ... 

Derive an expression relating the pressure drop for the turbulent flow of a fluid in a pipe to the heat transfer coefficient at the walls on the basis of the simple Reynolds analogy. Indicate the assumptions which are made and the conditions under which you would expect it to apply closely. Air at 320 K and atmospheric pressure is flowing through a smooth pipe of 50 mm internal diameter, and the pressure drop over a 4 m length is found to be 150 mm water gauge. By how much would you expect the air temperature to fall over the first metre if the. wall temperature there is 290 K ... 

It is normal practice to operate with a slight vacuum throughout the heater, so that air will leak in through sight-boxes and dampers, rather than combustion products leak out. Typically, the aim would be to maintain a vacuum of around 2 mm water gauge just below the convection section. 

Large storage tanks are designed to withstand low pressures and vacuums. Typically they are constructed to withstand no more than 8 in of water gauge pressure and 2.5 in of water gauge vacuum. A particular tank is 30 ft in diameter. 

Note A person can easily blow to a pressure of greater than 20 in of water gauge. 

A storage vessel contains liquid benzene at 100°F. The vessel vapor space is inerted with pure nitrogen to a total pressure of 1/2-in of water gauge. Assume that the vapor space is saturated with benzene vapor. 

Methyl alcohol liquid is stored in a vessel. Its vapor is inerted with nitrogen to a total pressure of 2 in of water gauge. Will the inerted vapor be flammable if it escapes the vessel Assume a temperature of 25°C. 

Storage tanks typically are not capable of withstanding much pressure or vacuum. Standard storage tanks are designed for a maximum of 2.5 in of water gauge vacuum (0.1 psi) and about 6 in of water gauge pressure (0.2 psi). 

Dermal/Ocular Effects. Volunteers including the report s author were exposed topically to liquid from a remote water gauge this liquid contained 1,2-dibromoethane as well as other chemicals (Pfiesser 1938). Follow-up tests were formed with 1,2-dibromoethane. No dermal changes occurred when the liquid or 0.5 cc of 1,2-dibromoethane was applied to uncovered skin. A burning sensation, inflammation and vesiculation occurred when a cloth dressing saturated with the liquid was applied for 1-2 hours. Skin lesions resolved with treatment after 7-13 days. 

Pflesser G. 1938. [Skin-damaging effect of ethylene dibromide, a constituent of the liquid from remote water gauges]. Archiv fuer Gewerbepathologie und Gewerbehygiene 8 591-600. (German). 

Replace water gauge at deluge valve with test gauge. Remove highest water spray nozzle in system and install test gauge. 

The fuel sample is cooled under the prescribed conditions and, at intervals of34°F (l°C),a vacuum of200 mm water gauge is applied to draw the fuel through a fine wire mesh filter. As the fuel cools below its cloud point, increasing amounts of wax crystals will be formed. These will cause the flow rate to decrease and eventually complete plugging of the filter will occur. 

Draft readings are a comparison of two pressures taken at the same elevation and are traditionally quoted in inches of water gauge. Whereas it is true that if you open an inspection port on a heater in an area of positive draft, you are liable to singe your eyebrows if you wish to really study or make sense of a set of draft readings for a furnace, you must first normalize the data. 

A steam gauge and water gauge are to be fitted to the boiler and the boiler and associate safety devices are to be inspected every 14 months. 

The example examined in this section is a storage reservoir system (Fig. 6-1) with a main feeder stream (70% of the total feeder stream at the Lawitz water gauge) and several smaller feeder streams into a first storage reservoir (Zeulenroda). The second storage reservoir (Weida) is directly connected to the first reservoir. Because only a few small direct feeder streams flow into this second reservoir, the first reservoir has a large influence on the quality of water in the second reservoir. 

The nitrate concentration was measured monthly from August 1976 to November 1992. Sampling for nitrate measurements was conducted at the water gauge in Lawitz and... 

Expressing w in lbs per sq ft, t in min, and v in ft per min, Williams et al determined the constant K for a number of dusts of different diameters. These are given in Table 84. The constant Kf may be termed the specific resistance and is expressed as in. water gauge per lb dust per sq ft filter area per lineal ft per min filtering velocity. The data contained in this table show that the resistance coefficient (1) increases with decreasing particle-size, and (2) does not vary greatly among several materials when compared at equivalent sizes. These facts are quite clear from Eq (21-5) since h varies inversely as d2. 

This equation gives the draft loss and shows that pressure-drop is independent of the dimensions of the cyclone. Expressed in inches of water gauge, Eq (21-9) may be written... 

---