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Fluids/Solids Handling Understand the Basics of Centrifugal Pump Operation By starting from such fundamentals as head and pressure, the authors have developed practical tips for specification and operation that provide for cost-effectiveness and reliability. Kimberly Fernandez, Bernadette Pyzdrowski, Drew W. Schiller and Michael B. Smith, KBR C entrifugal pumps are the most common type of kinetic pump, and are used most often in applications with moderate-to-high flow and low head. As the workhorse of the chemical process industries (CPI), centrifugals are almost always more economical to own, operate and maintain than other types of pumps. Parameters needed in specifying The process engineer is normally responsible for specifying the process requirements of the pump, including the conditions and physical properties of the liquid, and, most importantly, the ﬂowrate, pressure, density and viscosity. The ﬂowrate determines the capacity of the pump, and the head depends on the density and viscosity of the liquid. In general, the required ﬂowrate is determined by the material and energy balances. Design margins, typically between 0–25%, are added to the material-balance ﬂowrate to account for unexpected variations in properties or conditions, or to ensure that the overall plant meets its performance criteria. Also, minimum ﬂow protection is often added as continuous circulation. Occasionally, the required ﬂowrate (including design margins) may fall in the low range of that for centrifugal pumps. In such cases, a minimum-size pump rated for continuous service is speciﬁed, and the extra pump capacity is typically consumed by circulation from the discharge to the source. 52 www.cepmagazine.org May 2002 CEP During speciﬁcation, the maximum pressure a pump will develop during any aspect of operation, including startup, shutdown and upset conditions is determined. The shutoff pressure is the maximum pressure a pump will develop under zero-ﬂow conditions, which reﬂects a fully blocked outlet. Variables to consider when determining the design pressure include: • maximum pressure of the source (e.g., relieving pressure of a vessel) • maximum head developed by the pump (i.e., shutoff head) • maximum static head of the ﬂuid in the pump’s suction line • maximum pump operating speed (for variablespeed drives) • possibility of operator intervention during an upset. The head h is the most commonly used measurement of the energy at any point of the system, or of the system as a whole. It is deﬁned as: h=...
When using electric fireplaces, basic precautions should always be followed to reduce the risk of fire, electric shock and injury to persons, including the following: 1. Read all instructions before using this heater. 2. This fireplace is hot when in use. To avoid burns, do not let bare skin touch hot surfaces, such as surfaces near the heater outlet or light bulbs. Keep combustible materials such as clothes, pillows, furniture, bedding, papers and curtains at least 3 feet from the front of this appliance. 3. CAUTION: Whenever the heater is left operating and unattended, extreme caution is necessary if children or invalids are nearby. 4. Do not install the fireplace directly on carpet or a similar surface, which may restrict air circulation beneath the unit. 5. Always unplug fireplace when not in use. Disconnect the heater by turning controls to off then remove plug from outlet. 6. Fireplace is designed for indoor and household use only. 7. This fireplace is not intended for use in wet locations such as bathrooms, laundry areas and similar indoor locations. Never locate fireplace where it may fall into a bathtub or other water container. 8. If the fireplace shows any signs of damage or if the heater has malfunctioned. Return fireplace to authorized service for examination, adjustment or repair. 9. Do not run cord under carpeting or route cord under furniture or appliance.. Do not cover cord with throw rugs and runners. Arrange cord away from traffic areas and where it will not be tripped over. 10. Do not insert or allow foreign objects to enter any ventilation or exhaust opening as this may cause an electric shock, fire, or may damage the heater. 11. To prevent a possible fire, do not block heater outlet or any ventilation or exhaust in any manner. 12. All electrical heaters have hot and arcing or sparking parts inside. Do not use it in areas where gasoline, paint, or flammable liquids are used or stored or where the unit will be exposed to flammable vapours. 13. Extension cord may become overheat and may cause a risk of fire. If you have to use an extension cord, the cord shall be 16AWG minimum size and rate not less than 125V/15A or 2500 watts. 14. Always use properly grounded, fused and polarized outlets. 15. Always use ground fault protection where required by electrical code. 16. Always disconnect power before performing any cleaning, maintenance or relocation of the fireplace. 17. This appliance is not intended for use by persons (including children) with reduced physical, sensory or mental capabilities, or lack of experience and knowledge, unless they have been given supervision or instruction concerning use of the appliance by a person responsible for their safety. Children should be supervised to ensure that they do not play with the appliance. 18. CAUTION: In order to avoid a hazard due to inadvertent resetting of the thermal cutout, this appliance must not be supplied through an external switching device such as a timer, or connected to a circuit that is regularly switched on and off by the utility. 4|Page...
Valued Customer, We are pleased that you have chosen to purchase an electric fireplace manufactured by Dimplex North America Ltd. Over the years, valuable memories will occur around the warmth and comfort of your hearth. Thank you for allowing our product to be the backdrop for those special moments. 7204820200REV03 QUICK REFERENCE GUIDE FOR THE DIMPLEX ELECTRIC FIREPLACE 1. Before using the electric corner wall mounted fireplace verify: • Are the circuit breakers for the unit on? • Are the light bulbs loose? (to check, follow the instructions for replacing the light bulbs under the maintenance section of this manual) 2. The heater may emit a slight, harmless odor when first used. This odor is a normal condition caused by the initial heating of internal heater parts. 3. The information regarding the model of your unit can be found on the rating plate located inside the unit on the top left hand corner above the mirror. 4. If you have any questions or concerns regarding the operation of your fireplace, contact Dimplex customer service at 1-888-DIMPLEX (1-888346-7539).
This report provides a comprehensive analysis of the frozen bakery additives market, which is witnessing steady growth because of its diverse product portfolio. http://www.marketsandmarkets.com/Market-Reports/frozen-bakery-additives-market-1296.html
[289 Pages Report] Soil Treatment Market report categorizes global market of Pest & Weed Control, Organic Amendments and pH Adjusters by types and geography; forecasting revenue, volume and analyzing trends.
Fuel Additives Market report segments the market by ten mostly used additives types such as deposit control additives, cetane improvers, antioxidants, dyes & markers, lubricity improvers, cold flow improvers, stability improvers, corrosion inhibitors, octane improvers and anti-icing.
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Proppant Market report provides the estimates of the proppant market in terms of volume and value. It has been broken down into component regions and further split into countries
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EPDM Rubber (Ethylene Propylene Diene Monomer) Market report provides a comprehensive review of major market drivers, restraints, opportunities, winning imperatives, challenges and key issues in the market