Fans Ventilation A Practical Guide
Normal quantities and units used in fan technology
The fan and air movement industries within the English speaking world have for many years used a number of specialised units. These have been based on the imperial system, adapted as necessary. Often an arbitrary choice was made, for example pressure measured in inches water gauge. Table 22.11 gives a number of conversion factors designed […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Normal quantities and units used in fan technology отключены
Preferred numbers
22.4.1 General Standardisation is necessary if products are to be sold across national frontiers without problems of installation and operation. This applies in particular to dimensions to ensure that products can be purchased to a standard with the knowledge that it will fit in place of the same basic product manufactured by a different company […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Preferred numbers отключены
Other conversion factors
Hardness is not defined within the SI system. The following table can be used for conversion between the popular systems used. Tensile Strength Vickers hardness (F > 98 N) Brinell Hardness Rockwell hardness N/mm2 HV BHN HRB HRc 200 63 60 210 65 62 220 69 66 225 70 67 230 72 68 Tensile Strength […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Other conversion factors отключены
Conversion factors for SI units
A number of electrical terms evolved from the CGS system may still be encountered as well as units in the FPS system and other special units. In general it is best to convert units to the SI system before inserting quantities into equations as this will avoid problems involving conversion factors in the equations themselves. […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Conversion factors for SI units отключены
SI, The International System of Units
SI, Systиme Internationale d’Unitйs, the international measurement unit system, is not a completely new system. It is based on an earlier metric system and is coming more and more into world-wide use. The SI system is now systematically constructed to cover in practice all scientific, technical and daily requirements and is subject to international agreement. […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи SI, The International System of Units отключены
Units, conversions, standards and Preferred numbers
The modern SI system has been adopted in legislation by practically every country in the world. There are, however, extensive changeover problems and many different kinds of data are still only available in units which do not conform to the SI system. Chapter 22 attempts to bridge the difficulties experienced when dealing with quantities expressed […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Units, conversions, standards and Preferred numbers отключены
Pneumatic conveying
A conveying system of any kind is used to transport a material from one particular place to another. For the chosen method of pneumatic conveying, air is used as the transport medium. It is Or: VH = where: VH Equ 21.23 Applicable to most granular materials, be they in that form naturally or have to […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Pneumatic conveying отключены
Explosive atmospheres
On the 1st July 2003 the ATEX Directive of the European Union became a part of UK law. Whilst its provisions can, and do, affect all equipment used in hazardous areas, this Section concentrates on its requirements for fans. They are, after all, the prime mover in ventilation and air conditioning systems. Unfortunately there is […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Explosive atmospheres отключены
Dust and fume extraction
The intention of any local extract system is to reduce what could be a danger due to the pollution of the atmosphere by some mechanical or chemical process. It is imperative that the contaminant be captured as close as possible to its source by moving a mass of air across possible escape routes. An alternative […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Dust and fume extraction отключены
Mechanical draught
Gas, oil and coal fired boilers are used extensively to provide heating, hot water and steam for process applications, and in the generation of electrical power. In all cases where a fuel is being burnt, fans are used to provide combustion air, to transport exhaust gases and in some cases used to transport and deliver […]
Posted in: Fans Ventilation A Practical Guide | Комментарии к записи Mechanical draught отключены