Process Engineering Equipment Handbook Episode 3 Part 4 docx

FIG P-281 Untimed-screw pump (Source: Demag Delaval.) FIG P-282 Cutaway view of two-stage pump (Source: Demag Delaval.) The Transamerica DelavalTM CIG pump (see Fig P-282) is of the internal-gear type (see Fig P-278) In this type of pump, fluid is carried from the inlet to the discharge by a pair of gears consisting of one internal and one external gear The gears are placed eccentrically to each other and are separated by a crescent-shaped divider that provides a sealing path for the internal and external flow paths The internal-gear design is generally known for its quiet operation Modification of the gear profile also provides for reduction of the trapped oil, eliminating any pressure pulsations and thus reducing the noise level The design is extremely simple and allows gear sets to be stacked into a multistage arrangement for increased pressure rating With this arrangement, the pressure loads are distributed to reduce stress on the pump components, thus lengthening pump life The design also has the inherent feature of providing for a hydrodynamic film buildup on the bearings and external gear ring that eliminates metal contact between the working parts, also adding to pump life The design also provides for double pump configurations consisting of two independent pumps arranged on a common shaft, each pump having a separate discharge and sharing a common suction The TransamericaTM Delaval GTS pump is of the externally timed-screw type (see Fig P-283) The construction of this type of pump is conducive to operation on nonviscous liquids such as water that exclude the use of the IMO design This design relies on timing gears for phasing the mesh of the threads and support bearings at each end of the rotors to absorb the reaction forces With this FIG P-283 Cutaway view of externally timed-screw pump (Source: Demag Delaval.) FIG P-284 Cutaway view of double-end IMO pump (Source: Demag Delaval.) arrangement, the threads do not come into contact with each other or with the housing bores in which they rotate This feature, combined with the external location of the timing gears and bearings, which are oil-bath- or grease-lubricated, makes the pump suitable for handling nonviscous, corrosive, or abrasive fluids To provide for operation with corrosive or abrasive fluids, the pump housing can be supplied in a variety of materials including cast iron, ductile iron, cast steel, stainless steel, and bronze Moreover, the rotor bores can be lined with industrial hard chromium for additional abrasive resistance The rotors also may be supplied in a variety of materials including cast iron, heat-treated alloy steel, stainless steel, Monel, and Nitralloy The outside diameter of the rotors can be furnished with hard coatings including tungsten carbide, chromium oxide, and ceramics The IMO pump (see Fig P-284) falls into the untimed-screw category, and it will serve as a base for all further discussion of rotary pumps in general Because the fundamental characteristics of all rotaries are similar, many IMO pump features can be related to other types of rotaries without comment; however, when characteristics unique to the IMO pump are mentioned, they will be so identified Characteristics The IMO pump normally is offered as a three-screw type having no need for timing gears or conventional support bearings It is simple and rugged and has no valves or reciprocating parts to foul It can run at high speeds, is quietoperating, and produces a steady pulsation-free flow of fluid Properly applied, the IMO pump can handle a wide range of fluids from molasses to gasoline, including modern fire-resistant types, even to 5 percent soluble oil in water It can be made with hardened wear-resistant rotors to handle some types of contamination and abrasives Wide ranges of flow and pressure are available In the IMO pump, as in most screw pumps, it is the intermeshing of the threads on the rotors and the close fit of the surrounding housing that create one or more sets of moving seals between pump inlet and outlet These sets of seals act as a labyrinth and provide the screw pump with its positive-pressure capability Between successive sets of moving seals or threads are voids that move continuously from inlet to outlet These moving voids, when filled with fluid, carry the fluid along and provide a smooth flow to the outlet, which is essentially pulsationless Increasing the number of threads or seals between inlet and outlet increases the pressure capability of the pump, the seals again acting similarly to classic labyrinth seals The flow of fluid through the screw pump is parallel to the axis of the screws as opposed to the travel around the periphery of centrifugal, vane, and gear-type pumps This axial flow gives the screw pump ability to handle fluids at low relative velocities for a given input speed, and it is therefore suitable for running at higher speeds, with 1750 and 3500 rpm common for IMO pumps The fundamental difference between the IMO pump and other types of screw pumps lies in the method of engaging or meshing the rotors and maintaining the running clearances between them Timed-screw pumps require separate timing gears between the rotors to provide proper phasing or meshing of the threads Some sort of support bearing also is required at the ends of each rotor to maintain proper clearances and proper positioning of the timing gears themselves The IMO pump rotors are precision-made gearing in themselves, having mating generated thread forms such that any necessary driving force can be transmitted smoothly and continuously between the rotors without need for additional timing gears The center or driven rotor, called the power rotor, is in mesh with two or three close-fitting unsupported sealing, or idler, rotors symmetrically positioned about the central axis by the close-fitting rotor housing This close-fitting housing and the idlers provide the only transverse bearing support for the power rotor Conversely, the idlers are transversely supported only by the housing and the power rotor The real key to all IMO pump operation is the means employed for absorbing the transverse idler-rotor-bearing loads that are developed as a result of the hydraulic forces built up within the pump to move the fluid against pressure These rotors and the related housing bores are, in effect, partial journal bearings with a hydrodynamic fluid film being generated to prevent metal-to-metal contact This phenomenon is most often referred to as the journal-bearing theory, and IMO pump behavior is closely related to the applied principles of this theory The three key parameters of speed, fluid viscosity, and bearing pressure are related exactly as in a journal bearing If viscosity is reduced, speed must be increased or bearing pressure reduced in order not to exceed acceptable operating limits For a constant viscosity, however, the bearing-pressure capability can be increased by increasing TABLE P-30 Safe Axial-Velocity Limits for Various Fluids and Pumping Viscosities Fluid* Viscosity, SSU Velocity, ft/s Diesel oil Lubricating oil No C fuel oil Castor oil Cellulose 32 1,000 7,000 20,000 60,000 30 12 7 2 1 /2 * For characteristics of fuel oils see Table P-31 the speed It is this phenomenon that gives the IMO its high-speed capability; in fact, with proper inlet conditions, the higher the IMO pump speed the better the performance and the better the life This is directly opposite to most rotary-pump behavior Since the IMO pump is a displacement device, like all rotaries, it will deliver a definite quantity of fluid with every revolution of the power rotor If no internal clearances exist, this quantity, called theoretical capacity Qt, would depend only upon the physical dimensions of the rotor set and the speed Clearances, however, do exist, with the result that whenever a pressure differential occurs, there always will be internal leakage from outlet to inlet This leakage, commonly called slip S, varies with the pump type or model, amount of clearance, fluid viscosity at pumping conditions, and differential pressure For any given set of conditions, it is usually unaffected by speed The delivered capacity, or net capacity Q, therefore, is the theoretical capacity less slip The theoretical capacity of any pump can readily be calculated with all essential dimensions known Basically, IMO pump theoretical capacity varies directly as the cube of the power rotor’s outside diameter, which is generally used as the pumpsize designator Thus a relatively small increase in pump size can give a large increase in capacity Slip can also be calculated but usually is based upon empirical values developed by extensive testing Performance Inlet conditions The key to obtaining good performance from an IMO pump, as with all other rotaries, lies in a complete understanding and control of inlet conditions and the closely related parameters of speed and viscosity To ensure quiet, efficient operation, it is necessary to completely fill with fluid the moving voids between the rotor threads as they open to the inlet, and this becomes more difficult as viscosity, speed, or suction lift increases Basically, if the fluid can properly enter into the rotor elements, the pump will perform satisfactorily Remember that a pump does not pull or lift fluid into itself Some external force must be present to push the fluid into the voids Normally, atmospheric pressure is the only force present, but in some applications a positive inlet pressure is available Naturally the more viscous the fluid, the greater the resistance to flow and, therefore, the lower the rate of filling the moving voids of the threads in the inlet Conversely, light-viscosity fluids will flow quite rapidly and will quickly fill the moving voids It is obvious that if the rotor elements are moving too fast, the fill will be incomplete and a reduction in output will result The rate of fluid flow must always be greater than the rate of void travel or closing to obtain complete filling Safe rates of flow through the pump for complete filling have been found from experience when atmospheric pressure is relied upon to force the fluid into the rotors Table P-30 (see also Table P-31) gives these safe axial-velocity limits for various fluids and pumping viscosities TABLE P-31 Detailed Requirements for Fuel Oils a Viscosity Grade of Fuel Oilb No 1 2 4 5 6 Description Distillate oil intended for vaporizing pot-type burners and other burners requiring this gradec Distillate oil for generalpurpose domestic heating for use in burners not requiring No 1 Oil for burner installations not equipped with preheating facilities Residual-type oil for burner installations equipped with preheating facilities Oil for use in burners equipped with preheaters permitting a highviscosity fuel Carbon Water Residue and on 10% Sediment, Residuum, % % Max Max Flash Point, °F Min Pour Point, °F Max 100 or legal 0 Trace 100 or legal 20d 130 or legal Distillation Tem., °F Saybolt Universal at 100°F Kinematic Centistokes at Furol at 122°F 100°F 122°F Ash, % Max 10% Point Max 90% Point Max End Point Max Max Min Max Min Max Min Max Min Gravity, API Min 0.15 420 625 2.2 1.4 35 0.10 0.35 e 675 40 (4.3) 26 20 0.50 0.10 125 45 (26.4) (5.8) 130 or legal 1.00 0.10 150 40 150 or legal 2.00f 300 45 (32.1) (81) (638) (92) Reprinted by permission from Commercial Standard CS 12–48 on Fuel Oils of U.S Department of Commerce a Recognizing the necessity for low-sulfur fuel oils used in connection with heat treatment, nonferrous metal, glass, and ceramic furnaces, and other special uses, a sulfur requirement may be specified in accordance with the following table: Grade of fuel oil Sulfur, maximum % No 1 No 2 Nos 4, 5, and 6 0.5 1.0 No limit Other sulfur limits may be specified only by mutual agreement between the buyer and seller b It is the intent of these classifications that failure to meet any requirement of a given grade does not automatically place an oil in the next lower grade unless in fact it meets all requirements of the lower grade c No 1 oil shall be tested for corrosion for 3 h at 122°F The exposed copper strip shall show no gray or black deposit d Lower or higher pour points may be specified whenever required by conditions of storage or use However, these specifications shall not require a pour point lower than 0°F under any conditions e The 10 percent point may be specified at 440°F; maximum for use in other than atomizing burners f The amount of water by distillation plus the sediment by extraction shall not exceed 2.00 percent The amount of sediment by extraction shall not exceed 0.50 percent A deduction in quantity shall be made for all water and sediment in excess of 1.0 percent It is thus quite apparent that pump speed must be selected to satisfy the viscosity of the fluid to be pumped The pump manufacturer generally must supply the determination of the axial velocity through a screw pump, although the calculation is quite simple when the driving-rotor speed and screw-thread lead are known The lead is the advancement made along the thread during a complete revolution of the rotor as measured along the axis In other words, it is the travel of the fluid slug in one complete revolution In this handbook, the more general term fluid is used to describe the fluids handled by rotaries that may contain or be mixed with matter in other than the liquid phase The word liquid is used only to describe true liquids that are free of vapors and solids Most of the fluids handled by rotary pumps, especially petroleum oils, because of their complex nature contain certain amounts of entrained and dissolved air or gas that is released as vapor when the fluid is subjected to pressures below atmospheric If the pressure drop required to overcome entrance losses to push such a fluid into the rotor voids is sufficient to reduce the pressure so that vapors are released in the rotor voids, cavitation results This leads to noisy operation and an attendant reduction in output It is therefore very important to be aware of the characteristics of the entrained air and gas of the fluids to be handled In fact, it is so important that a more detailed study of this relatively complex subject is included below in the subsection “Effect of Entrained or Dissolved Gas on Performance.” Speed The speed N of a rotary pump is the number of revolutions per minute of the driving rotor In most instances this is the input shaft speed; however, in some geared-head units the driving-rotor speed can differ from the input shaft speed Capacity The actual delivered capacity of any rotary pump, as stated earlier, is theoretical capacity less internal leakage or slip when handling vapor-free fluids For a particular speed, this may be written Q = Qt - S, where the standard unit of Q and S is the U.S gallon per minute Again, if the differential pressure is assumed to be zero, the slip may be neglected and Q = Qt The term displacement D is of some general interest, although it is no longer used in rotary-pump calculations It is the theoretical volume displaced per revolution of the driving rotor and is related to theoretical capacity by speed The standard unit of displacement is cubic inches per revolution; thus Qt = DN ÷ 231 The terms actual displacement and liquid displacement are also less frequently used for rotary-pump calculations but continue to be used for some theoretical studies Actual displacement is related to delivered capacity by speed The actual delivered capacity of any specific rotary pump is reduced by 1 Decreasing speed 2 Decreased viscosities 3 Increased differential pressure The actual speed must always be known and most often differs somewhat from the rated or nameplate specification This is the first item to be checked and verified in analyzing any pump’s operating performance It is surprising how often the speed is incorrectly assumed and later found to be in error Because of the internal clearances between rotors and the housing of a rotary pump, lower viscosities and higher pressure increase slip, which results in a reduced delivered capacity for a given speed The impact of these characteristics can vary widely for the various types of rotary pumps encountered The slip, however, is not measurably affected by changes in speed and thus becomes a smaller percentage of the total flow with the use of higher speeds This is a very significant FIG P-285 Cutaway view of single-end IMO pump; two closures (Source: Demag Delaval.) factor in dealing with the handling of light viscosities at higher pressures, particularly in the case of devices, such as the IMO pump, that favor high speed Always run at the highest speed possible for best results and best volumetric efficiency with the IMO pump This will not generally be the case with rotaries having support-bearing speed limits Pump volumetric efficiency Vy is calculated as Vy = Q/Qt = (Qt - S)/Qt, with Qt varying directly with speed As stated previously, theoretical capacity of an IMO pump is a function that varies directly as the cube of the power rotor’s outside diameter for a standard three-rotor pump configuration For a constant speed, a 2-in rotor will have a theoretical capacity 8 times that of a 1-in rotor size However, for a given model, slip varies directly as the square of the rotor size; therefore, the slip of the 2-in rotor is 4 times that of a 1-in rotor with all fluid variables held constant On the other hand, viscosity change affects the slip inversely to some power which has been determined empirically An acceptable approximation for 100 to 10,000 SSU is obtained by using the one-half power Slip varies directly with approximately the square root of differential pressure, and a change from 400 to 100 SSU will double the slip just as a differential-pressure change from 100 to 400 lb/in2 Pressure The pressure capability of different types of rotary pumps varies widely Some of the gear and lobe types are fairly well limited to 100 lb/in2, normally considered low pressure Other gear and vane types perform very well in the moderate-pressure range (100 to 500 lb/in2) and beyond Some types can operate well in the high-pressure range, while others such as axial piston pumps can work at 5000 lb/in2 and above The slip characteristic of a particular pump is one of the key factors that determine the acceptable operating range, which generally is well defined by the pump manufacturer; however, all applications for high pressure should be approached with some caution, and the manufacturer or the manufacturer’s representative should be consulted The IMO pump is suitable for a wide range of pressures from 50 to 5000 lb/in2, dependent upon the selection of the right model Internal leakage can be restricted for high-pressure applications by introducing increased numbers of moving seals or threads between inlet and outlet (see Figs P-285 through P-287) The number of seals between inlet and outlet normally is specified for a particular model in terms of number of closures The number of closures is increased to obtain higher-pressure capability, which also results in increased pump length for a given rotor size FIG P-286 Cutaway view of single-end IMO pump; five closures (Source: Demag Delaval.) FIG P-287 Cutaway view of single-end IMO pump; 11 closures (Source: Demag Delaval.) TABLE P-32 IMO Pumps Number of Closures Maximum Pressure, lb/in2 1 2 3 5 11 100 500 1500 3000 5000 IMO pumps generally are available with predetermined numbers of closures versus maximum pressure rating when rated at 150 SSU and 3500 rpm in the 10- to 100-gal/min range (see Table P-32) Horsepower The brake horsepower (bhp) required to drive a rotary pump is the sum of the theoretical liquid horsepower and the internal power losses The theoretical liquid horsepower is the actual work done in moving the fluid from its inlet-pressure condition to the outlet at discharge pressure Note: This work is done on all the fluid of theoretical capacity, not just delivered capacity, because slip does not exist until a pressure differential occurs Rotarypump power ratings are expressed in terms of horsepower (550 ft·lb/s), and theoretical liquid horsepower can be calculated: tLhp = QtDP ÷ 1,714 It should be noted that the theoretical liquid horsepower is independent of viscosity and is concerned only with the physical dimensions of the pumping elements, the rotative speed, and the differential pressure Internal power losses are of two types: mechanical and viscous Mechanical losses include all the power necessary to overcome the mechanical friction drag of all the moving parts within the pump, including rotors, bearings, gears, mechanical seals, etc Viscous losses include all the power lost from the fluid viscous-drag effects against all the parts within the pump as well as from the shearing action of the fluid itself It is probable that the mechanical loss is the major component when operating at low viscosities and high speeds while the viscous loss is the larger at high viscosity and slow-speed conditions No direct comparison can easily be made between various types of rotary pumps for internal power loss, as this falls into the category of closely guarded trade secrets Most manufacturers have established their own data on the basis of tests made under closely controlled operating conditions, and they are very reluctant to divulge their findings In general, the losses for a given type and size of pump vary with viscosity and rotative speed and may or may not be affected by pressure, depending upon the type and model of pump under consideration These losses, however, must always be based upon the maximum viscosity to be handled since they will be highest at this point The actual pump power output (whp), or delivered liquid horsepower, is the power imparted to the fluid by the pump at the outlet It is computed in the same way as theoretical liquid horsepower, using Q in place of Qt; hence the value will always be less Pump efficiency is the ratio of whp to bhp In the application of rotary pumps certain basic factors must be considered to ensure a successful installation These factors are fundamentally the same regardless of the fluids to be handled or the pumping conditions The pump selection for a specific application is not difficult if all the operating conditions are known It is often quite difficult, however, to obtain accurate information as to these conditions This is particularly true of inlet conditions and viscosity, since it is a common feeling that inasmuch as the rotary pump is a positive-displacement device, these items are unimportant In any rotary-pump application, regardless of the design, suction lift, viscosity, and speed are inseparable Speed of operation, therefore, is dependent upon viscosity and suction lift If a true picture of these two items can be obtained, the problem of making a proper pump selection becomes simpler, and it is probable that the selection will result in a more efficient unit Application and selection Viscosity It is not very often that a rotary pump is called upon to handle fluids having a constant viscosity Normally, because of temperature variations, it is expected that a range of viscosity will be encountered, and this range can be quite wide; for instance, it is not unusual that a pump is required to handle a viscosity range of 150 to 20,000 SSU, the higher viscosity usually being due to cold-starting conditions This is a perfectly satisfactory range insofar as a rotary pump is concerned; but if information can be obtained concerning such things as the amount of time during which the pump is required to operate at the higher viscosity and whether or not the motor can be overloaded temporarily, a multispeed motor can be used, or the discharge pressure can be reduced during this period, a better selection can often be made TABLE P-36 Multistage Pumps Design Criteria SI Units 80 to 400 mm 230 to 660 mm to 3200 m3/h to 3000 m to 310 bar to 204°C to 6500 rpm Discharge size Impeller diameter Capacity Head Pressure Temperature Speed U.S Units 3 to 16 in 9 to 26 in to 14,000 gpm to 9850 ft to 4500 psi to 400°F to 6500 rpm including water, gasoline, propanes, and light products, as well as hard-to-handle crude oil Applications include ᭿ Refinery use ᭿ Petrochemical plants ᭿ Gas processing ᭿ Coal processing ᭿ Offshore installation Design features These include: ᭿ In-line suction and discharge nozzles ᭿ Full compliance with API 610 8th edition specifications ᭿ Overhung, vertical in-line, integral bearing frame, flexibly coupled pump ᭿ Seal chamber designed to accommodate all single and dual cartridge seal configurations; complies fully with API 682 specification Table 1 ᭿ Back pullout device See Figs P-307 through P-313 and Table P-38 Materials Standardized API 610 material classes: S-4, S-6, C-6 and A-8 Other material combinations are available CVAR rigid coupled pump See Fig P-314 and Table P-39 API 610 with rigid or flexible coupling See Figs P-315 through P-321 and Tables P-40 through P-42 API 610 double suction between bearings process pump CD8 type Application ranges These pumps (designated CD8) are designed for pumping applications covering the full range of refinery services, including water, gasoline, propanes, and light products, as well as hard-to-handle crude oil and fractionator bottoms Applications include: ᭿ Refinery ᭿ Petrochemical plants ᭿ Gas processing TABLE P-37 Multistage Pump Design Features and Benefits Features Advantages Benefits ᭿ Large bore ᭿ Accommodates nonmetallic wear parts ᭿ Increased efficiencies, nongalling ᭿ Full range of design pressures ᭿ Satisfies many applications ᭿ Case appropriate for application ᭿ Established hydraulic designs ᭿ Optimum match of operating requirements to the pump ᭿ Lower operating cost ᭿ State-of-the-art pattern equipment ᭿ High-quality castings ᭿ Predictable production and performance ᭿ Accessible fasteners for internal parts ᭿ Ease of assembly and disassembly ᭿ Lower maintenance cost ᭿ Preengineered bleed-off connection at optimal location ᭿ Handles multiple requirements ᭿ Eliminates additional pump and reduces capital cost ᭿ Axially split ᭿ Ease of disassembly and inspection ᭿ Lower maintenance cost ᭿ Opposed impeller design Case ᭿ Minimizes axial thrust ᭿ Optimum bearing life ᭿ Double volute design ᭿ Minimizes radial thrust ᭿ Optimum seal and bearing life ᭿ Full range of hydraulics ᭿ Higher head per stage and higher efficiency ᭿ Lower operating cost ᭿ Precision investment pattern equipment ᭿ Repeatable high-quality castings with a smooth surface finish ᭿ On time delivery, predictable and repeatable performance ᭿ Optional impeller/rotor balance to 4 W/n Impeller ᭿ Reduces vibration ᭿ Improved mean time between maintenance ᭿ Optional integral wear ring ᭿ Lower maintenance cost ᭿ Accommodates double and tandem cartridge seals with ease of access for maintenance ᭿ Reduced seal inventories ᭿ Easy coupling removal ᭿ Lower maintenance cost ᭿ INPROTM bearing isolators ᭿ Minimizes lubricant contamination ᭿ Promotes longer bearing life ᭿ Finned housing ᭿ Increased heat transfer area ᭿ Eliminates the requirement for costly water or product cooling ᭿ Optional fan cooling ᭿ Improved convective heat dissipation ᭿ Eliminates the requirement for costly water or product cooling ᭿ Optional fin tube cooler ᭿ Additional cooling efficiency ᭿ Increased life for bearings ᭿ Ring oil lubrication Baseplate ᭿ Reduced maintenance cost ᭿ Accommodates double and tandem cartridge seals with ease of access for maintenance ᭿ NEMA tapered shaft extension Bearing housing ᭿ Reduced number of parts ᭿ Bearing bracket enlarged and extended ᭿ API 682 compliance Shaft and seal chamber ᭿ Self-contained lubrication design ᭿ Reduced installation and maintenance cost ᭿ Standardized designs for most sizes ᭿ Predictable and repeatable installation details ᭿ Shorter delivery lead times ᭿ Optional job specific baseplates ᭿ Accommodates high nozzle loads with minimum shaft deflection ᭿ Increased operating reliability ᭿ Optional job specific baseplates ᭿ Preengineered installation details ᭿ Reduced stress concentration on foundation pad ᭿ Complies with API 610 8th edition ᭿ Shorter delivery lead times ᭿ Increased operating reliability ᭿ Increased operating reliability LARGE MSD's FIG P-306 Hydraulic range chart: multistage pumps (Source: Sulzer Pumps.) FIG P-307 Vertical inline pump, type CVA8 (Source: Sulzer Pumps.) ᭿ Coal processing ᭿ Offshore installation Design features These include ᭿ Full compliance with API 610 8th edition specifications ᭿ Horizontal, between bearings, radially split, centerline mounted, top suction, top discharge, heavy duty process pump with enclosed type double entry (suction) impeller ᭿ Fully confined gaskets between case, cover, and seal gland plate ᭿ Seal chamber designed to accommodate all single, tandem, dual and cartridge seal configurations; complies fully with API 682 specification Table 1 Some newer manufacturing techniques used in making these pumps are discussed in Figs P-302 through P-305 See Tables P-43 and P-44 as well as Figs P-322 through P-332 Materials Standardized API 610 material classes: S-4, S-6, C-6 and A-8 Other material combinations are available Heavy duty double case multistage pumps This information source designates its radially split, double-volute, double-case, horizontal multistage pump designed for high-pressure, high-speed, high-temperature services requiring reliability and long service life as “Type CP.” The CP’s rotating element is housed in a horizontally split inner case, which is itself contained in a cast or forged outer barrel This design provides for easy maintenance and element removal without piping disturbance FIG P-308 Design features, type CVA8 (Source: Sulzer Pumps.) FIG P-309 Oil mist (CVA8 option) Pure oil mist option; complete with connections and oil drain reservoir (Source: Sulzer Pumps.) FIG P-310 Oil mist system (CVA8 option) Stand-alone oil mist generator; integrally mounted; ready for plant air hookup (Source: Sulzer Pumps.) FIG P-311 Back pull-out tooling (CVA8 option) Available for all pump sizes; ease of in-situ maintenance (Source: Sulzer Pumps.) FIG P-312 Hydraulic range chart (CVA8 type) (Source: Sulzer Pumps.) Suction and discharge nozzles are normally positioned at top centerline, but can be rotated to meet specific application requirements Also, CP can be supplied with a double-suction first-stage for low NPSH The opposed impeller and double volute inner case minimize axial thrust and control radial balance CP is used principally for specialized refinery and industrial services, and for boiler feed applications in power plants See Figs P-333 and P-334 General specifications Capacities to 15,000 gpm (3400 m3/h) Heads to suit Speeds to 7200 rpm Temperatures to 800°F (425°C) Pressure (hydrotest) to 6000 psi (410 bar) Applications Petroleum: ᭿ Refinery and petrochemical services ᭿ Production services FIG P-313 Hydraulic range chart (CVA8 type) (Source: Sulzer Pumps.) TABLE P-38 CVA8 Pumps Operating Data SI Units U.S Units Discharge sizes Capacities Heads Pressures Temperatures Speeds 25 to 250 mm to 1070 m3/h to 220 m to 50 bar to 230°C to 3600 rpm 1 to 10 in to 4700 gpm to 720 ft to 735 psi to 450°F to 3600 rpm Power: ᭿ Boiler feed Options that can be supplied ᭿ ᭿ ᭿ These typically include Double-suction first stage Suction/discharge nozzle orientation Bearing arrangements and lube systems FIG P-314 Offered as a low-cost alternative to the horizontal overhung and integral thrust bearing frame flexible coupled vertical in-line Includes equivalent hydraulic performances and many mechanical features required by API services Includes four-piece rigid coupling design that transmits thrust load from the pump to the driver Freestanding vertical in-line configuration; API 682 Table 1 seal chamber; interchangeable components with CAP8 and CVA8; rigid four-piece coupling (Source: Sulzer Pumps.) ᭿ ᭿ ᭿ ᭿ ᭿ Seals and piping Stuffingbox covers Cooling jackets Custom baseplates for special drivers Metallurgy combinations TABLE P-39 CVA8 Features, Functions, and Benefits Features Functions Benefits ᭿ Volute case design capable of withstanding two times API 610 nozzle loads ᭿ In-line suction and discharge nozzles ᭿ Supports typical piping installation ᭿ Arranged for installation in pipe ᭿ Simplified piping arrangement ᭿ Reduced vibration at peak efficiency conditions ᭿ Increased life for bearings and seals ᭿ Positive location and compression ᭿ Simplified assembly ᭿ Improved sealing reliability ᭿ Reduced emissions ᭿ Pressure rating equivalent to ANSI B16.5 Cl 300 designed per ASME Section VIII Division 1 ᭿ Long service life ᭿ Standard pressure class rating ᭿ Nss < 11,000 (S < 214) ᭿ Reduced vibration at low flows ᭿ Long bearing and seal life and flexibility of operation ᭿ Reduced NPSHr ᭿ Lower vessel height and greater NPSH margins ᭿ Enclosed design adjustment ᭿ High efficiencies and no impeller-reduced maintenance ᭿ Lower operating cost and reduced maintenance ᭿ Wide performance range match application requirements ᭿ Broad selection of hydraulics to single vendor for all applications ᭿ Reduced operating cost and single vendor for all applications ᭿ Optimized shaft diameter to overhang ratio ᭿ Lower shaft deflection at seal ᭿ Longer seal life and lower maintenance cost ᭿ Positive shouldering of bearing Bearing assembly ᭿ Minimal foundation preparation ᭿ Nongrouted ᭿ Nss < 14,000 (S < 271) Seal chamber ᭿ Supports all equipment ᭿ Heavy duty construction with 1/8 in (3 mm) corrosion allowance Shaft ᭿ Simplified piping arrangement and foundation design ᭿ Fully confined controlled compression gasket Impeller ᭿ Allows installation in pipeline with minimal footprint ᭿ Double volute (4 in and larger) Pressure casing ᭿ Vertical in-line assembly ᭿ Freestanding Design ᭿ Assures proper assembly ᭿ Reduced maintenance time and longer operating periods ᭿ Seal chamber designed to API 682 Table 1 dimensions ᭿ Allows installation of API 682 seals ᭿ Cartridge seals ᭿ Simplified assembly ᭿ Self-contained oil-lubricated angular contact thrust bearing ᭿ All loads accommodated by the pump ᭿ Allows standard driver selection ᭿ Grease lubricated radial bearing ᭿ Carries transmitted radial loads and controls shaft orbit ᭿ Low maintenance and improved seal life ᭿ Improved sealing reliability ᭿ Reduced emissions ᭿ Standard seals interchangeable between CAP8 and CVAR ᭿ Oil mist lubrication ᭿ Clean cool lubrication ᭿ Improved bearing life ᭿ INPROTM shaft seals ᭿ Minimum external contamination of oil ᭿ Longer bearing life and extended operating periods ᭿ Fan cooling standard >3,000 rpm or >250 °F ᭿ No external coolant required for bearings ᭿ Reduced installation cost for utilities and operating costs FIG P-315 API 610 8th edition compliant rigid coupled without bearing housing (Source: Sulzer Pumps.) FIG P-316 API 610 8th edition compliant flexible coupled with integral thrust bearing (Source: Sulzer Pumps.) FIG P-317 VC2R8 commercial standard API 682, Table 1, seal chamber dimensions; nozzle load capability per API 610; integral mounting plate; optional suction can thicknesses available; flanged and bolted columns with optional O-rings; single piece shaft construction £ 16 feet; flanged and bolted bowls with register fit; hydraulically balanced impellers; keyed and axially retained impellers (Source: Sulzer Pumps.) FIG P-318 Hydraulic range chart (Type VR 8) (Source: Sulzer Pumps.) ᭿ ᭿ ᭿ ᭿ Vibration detectors Seal leakage detectors Temperature detectors Temperature insulation Vacuum Pumps* An amazing number of process plant applications require vacuum systems for continuous or intermittent services Central vacuum systems are often found in power stations and in industrial and marine installations for the purpose of priming * Sources: As acknowledged in captions to illustrations Pumps P-309 FIG P-318 Hydraulic range chart (Type VR 8) (Source: Sulzer Pumps.) ᭿ ᭿ ᭿ ᭿ Vibration detectors Seal leakage detectors Temperature detectors Temperature insulation Vacuum Pumps* An amazing number of process plant applications require vacuum systems for continuous or intermittent services Central vacuum systems are often found in power stations and in industrial and marine installations for the purpose of priming * Sources: As acknowledged in captions to illustrations ... 42 0 625 2.2 1 .4 35 0.10 0 .35 e 675 40 (4 .3) 26 20 0.50 0.10 125 45 (26 .4) (5.8) 130 or legal 1.00 0.10 150 40 150 or legal 2.00f 30 0 45 (32 .1)... See Figs P -33 3 and P -33 4 General specifications Capacities to 15,000 gpm ( 34 00 m3/h) Heads to suit Speeds to 7200 rpm Temperatures to 800°F (42 5°C) Pressure (hydrotest) to 6000 psi (41 0 bar) Applications... pumps are discussed in Figs P -30 2 through P -30 5 See Tables P- 43 and P -44 as well as Figs P -32 2 through P -33 2 Materials Standardized API 610 material classes: S -4, S-6, C-6 and A-8 Other material