Valves Flanged, Threaded, and Welding End ASME B16.34-2013

Valves — Flanged,
Threaded, and
Welding End
ASME B16.34-2013

This Standard applies to new construction and covers pressure–temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end and wafer or flangeless valves of steel, nickel-base alloys, and other alloys shown in Table 1. Wafer or flangeless valves, bolted or through-bolt types, that are installed between flanges or against a flange are treated as flanged-end valves. Alternative rules for NPS 21⁄2 and smaller valves are given in Mandatory Appendix V.

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ASME Orientation and Guide for Use of SI (Metric) Units

ASME
Orientation and
Guide for Use of
SI (Metric) Units


This booklet includes: SI Base and Supplementary Units, Rules For Use Of SI Units In ASME Publications, Conversion and Rounding, Dimensioning, Units Outside The International System, Units Not To Be Used In ASME Documents, SI Units For ASME Use, and Methods Of Reporting SI Equivalents For Existing Standards Under Revision. It also includes tables on SI Base Units, Units In Use With International System, Units To Be Used With The International System For A Limited Time, CGS Units With Special Names and SI Units For ASME Use.

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Pipeline Engineering 1st Edition Henry Liu

Pipeline Engineering

1st Edition

Henry Liu

Pipeline engineering has struggled to develop as a single field of study due to the wide range of industries and government organizations using different types of pipelines for all types of solids, liquids, and gases. This fragmentation has impeded professional development, job mobility, technology transfer, the diffusion of knowledge, and the move

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TAHOE DESIGN SOFTWARE HYDROFLO 2

TAHOE DESIGN SOFTWARE
 HYDROFLO 2

HYDROFLO 2 is a unique fluid conveyance system design tool for full pipe incompressible flow conditions. It makes it easy to model and analyze fluid transport systems found in industrial process, water supply, petroleum transport, mining de-watering and HVAC systems. During the design process, you view a vertical elevation-scaled representation of your fluid conveyance system in HYDROFLO's workspace. Elements (such as pipes, valves, etc.) can be added to your design with drag-and-drop and cut-and-paste ease. HYDROFLO's clipboard enables near instant creation of duplicate parallel lines. Element data and analysis results can be viewed simply by placing the cursor over an element. HYDROFLO's Group Editor eliminates repetitive and tedious editing tasks

The Importance of Detailed System Analysis

A liquid transport system must be accurately defined and analyzed for its intended operation before the proper pump can be specified for it. The operational steady-state and dynamic flows and pressures for various operational strategies must be known so that pipe and pump sizes and system strengths can be determined. Many costs and safety considerations must also be addressed. No single pump can satisfy the flow and pressure requirements of all systems. If the wrong pump is selected for  an application, it can result in additional expenses and/or dangerous operating conditions. Many considerations are involved in the selection of a pump for a specific application:

• Liquid properties
• Pump construction materials
• Pump performance throughout a range of operating conditions
• NPSHA to the pump
• Pump speed
• Differential head required

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Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries ISO 15761

Steel gate, globe and check valves for sizes
DN 100 and smaller, for the petroleum and
natural gas industries
ISO
15761



Introduction
The purpose of this International Standard is to establish basic requirements and practices for socket-welding, buttwelding, threaded and flanged end, steel gate, globe and check valves with reduced body seat openings, whose general construction parallels that specified by the American Petroleum Institute standard API 602[1] and the British Standard BS 5352[2].
The form of this International Standard corresponds to ISO 6002[3] and ISO 10434[4]. However, it is not the purpose of this International Standard to replace ISO 6002, ISO 10434 or any other International Standard not identified with petroleum or natural gas industry applications.

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TYPES OF CHECK VALVES

TYPES OF CHECK VALVES

The Development of a Simulation Model of Pipeline Network Systems with Check Valve Tianhe We

The Development of a Simulation Model of
Pipeline Network Systems with Check Valve
Tianhe We

The objective of this thesis is to design and implement a software package to rnodel and simulate pipeline network systens with check valves. The application package is written under the window's environment to provide the hydraulic engineer a user friendly interface for case of simulation and analysis without requiring to write code.
Discussion of the phenomenon of hydraulic transients, derivation of the differential equations, comparison of different kinds of analysis methods, and investigation of the method of characteristics solution and basic boundary conditions are ai1 established. The check vdve dynamic equation is investigated for the analysis of pipeline transients, and formulate for flow torque acting on the valve discs are derived by introducing the orifice sequence model. 
Dynamic behavior of pumps is considered during the pipeline transients, and the analysis of this behavior combines the method of characteristics with check valve dynarnics, pump characteristic and pump boundary conditions both for pump failure and pump start up. Numericd solutions to pipeline transients, check vaive dynamicq and pump characteristic are established. Finally, the implementation into a working simulation program of a dynamic model for pipeline network systerns with check valves is described, and a user guide for the software HyrioAmlps and HyrioGruphic is presented

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.

compact steel gate valves flanged , threaded , welding and extended body ends API 602

compact steel gate valves
flanged , threaded , welding and
extended body ends
API 602

Gate, Globe, and Check Valves for Sizes DN 100 (NPS 4) and Smaller for the Petroleum and Natural Gas Industries, Tenth Edition, Includes Errata (September 2016)

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Specification for Steel check valves (flanged and butt-welding ends) for the petroleum, petrochemical and allied industries BS 1868:1975

Specification for
Steel check valves
(flanged and
butt-welding ends) for
the petroleum,
petrochemical and
allied industries
BS 1868:1975


This British Standard specifies requirements for cast or forged steel check valves with flanged or
butt-welding ends of the following types:
a) swing, for vertical or horizontal flow 
b) lift:
i) piston type, for angle or horizontal flow 
ii) ball type, for angle or horizontal flow 
iii) ball type, for vertical flow
iv) disk type, for vertical flow 
The terms “vertical”, “horizontal” and “angle” relate to the axes of the body ends.
When swing check valves are used in vertical lines the flow must be in an upward direction. For the
purposes of this standard any line with a slope (upward or downward) of 5° or less is deemed to be
horizontal. In the case of angle pattern valves the inlet should be vertical.

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An Introduction To Check valve Types , Principles ,And Application

An Introduction To Check valve
Types , Principles ,And Application 

Introduction 
Check valves are designed to prevent the reversal of flow in a piping system. These valves are
activated by the flowing material in the pipeline. The pressure of the fluid passing through the
system opens the valve, while any reversal of flow will close the valve. Closure is accomplished
by the weight of the check mechanism, by back pressure, by a spring, or by a combination of
these means. The general types of check valves are swing, tilting-disk, piston, butterfly, and
stop.

Valve Types
There are essentially four major types of check valves:
· Swing Check Valves
· Tilting Disk Check Valves
· Lift Check Valves
· Dual Disk In-Line Check Valves

1- Swing Check Valves
A swing check valve is illustrated in Figure 1. The valve allows full, unobstructed flow and automatically closes as pressure decreases. These valves are fully closed when the flow reaches
zero and prevent back flow. Turbulence and pressure drop within the valve are very low.
A swing check valve is normally recommended for use in systems employing gate valves because
of the low pressure drop across the valve. Swing check valves are available in either Y-pattern
or straight body design. A straight check valve is illustrated in Figure 1. In either style, the disk and hinge are suspended from the body by means of a hinge pin. Seating is either metal-tometal or metal seat to composition disk. Composition disks are usually recommended for services where dirt or other particles may be present in the fluid, where noise is objectionable, or where positive shutoff is required.

FIG 1

Straight body swing check valves contain a disk that is hinged at the top. The disk seals against the seat, which is integral with the body. This type of check valve usually has replaceable seat rings. The seating surface is placed at a slight angle to permit easier opening at lower pressures, more positive sealing, and less shock when closing under higher pressures. Swing check valves are usually installed in conjunction with gate valves because they provide relatively free flow. They are recommended for lines having low velocity flow and should not be used on lines with pulsating flow when the continual flapping or pounding would be destructive to the seating elements. This condition can be partially corrected by using an external lever and weight.

2- Tilting Disk Check Valves

The tilting disk check valve, illustrated in Figure 2, is similar to the swing check valve. Like
the swing check, the tilting disk type keeps fluid resistance and turbulence low because of its
straight-through design
Tilting disk check valves can be installed in horizontal lines and vertical lines having upward Figure 2 Operation of Tilting Disk Check Valve flow. Some designs simply fit between two flange faces and provide a compact, lightweight installation, particularly in larger diameter valves.

FIG 2

The disk lifts off of the seat to open the valve. The airfoil design of the disk allows it to "float"
on the flow. Disk stops built into the body position the disk for optimum flow characteristics.
A large body cavity helps minimize flow restriction. As flow decreases, the disk starts closing
and seals before reverse flow occurs. Back pressure against the disk moves it across the soft seal
into the metal seat for tight shutoff without slamming. If the reverse flow pressure is insufficient
to cause a tight seal, the valve may be fitted with an external lever and weight.
These valves are available with a soft seal ring, metal seat seal, or a metal-to-metal seal. The
latter is recommended for high temperature operation. The soft seal rings are replaceable, but
the valve must be removed from the line to make the replacement.

3- Lift Check Valves
A lift check valve, illustrated in Figure 3, is commonly used in piping systems in which globe
valves are being used as a flow control valve. They have similar seating arrangements as globe
valves.
Lift check valves are suitable for installation in horizontal or vertical lines with upward flow.
They are recommended for use with steam, air, gas, water, and on vapor lines with high flow
velocities. These valves are available in three body patterns: horizontal, angle, and vertical.

FIG 3

Flow to lift check valves must always enter below the seat. As the flow enters, the disk or ball
is raised within guides from the seat by the pressure of the upward flow. When the flow stops
or reverses, the disk or ball is forced onto the seat of the valve by both the back flow and
gravity.
Some types of lift check valves may be installed horizontally. In this design, the ball is
suspended by a system of guide ribs. This type of check valve design is generally employed in
plastic check valves.
The seats of metallic body lift check valves are either integral with the body or contain
renewable seat rings. Disk construction is similar to the disk construction of globe valves with
either metal or composition disks. Metal disk and seat valves can be reground using the same
techniques as is used for globe valves.
3-1  Ball Type Lift Check Valves
Ball check valves are very similar in design to piston check valves, except the piston closing element is replaced with a spherical ball. The advantage of using a ball as the closing device is that the ball can rotate with flow, utilizing the entire spherical area as a seating surface. Used in viscous services and services where particulates are present, the increased available seating surface and the rotation during flow help to keep the spherical

FIG 4

ball’s surface “clean”. Most manufacturers offer ball check valves in small pipe sizes (two inch and under). Like piston lift check valves, ball check valves have higher pressure losses than equally sized tilting disk and swing check valves. Additionally, the required differential pressure for tight shut-off can be quite erratic. Ball check valves are generally not recommended for tight shut-off applications with differential pressures under 100 psi without special resilient valve seats.

3-2 Piston Type Lift Check Valve
Generally, piston style lift check (also commonly referred as a piston check valve) valve bodies are of Y-pattern design, with the flow coming up underneath the piston closing element. Note that this arrangement is similar to a globe valve. The closing element is normally contained in a cage-type guiding element to control lateral movement of the piston, assuring alignment during opening and closing.
Manufacturers frequently design piston lift check valves with springs above the piston to increase the closing speed. Seat contact between the piston seat and the valve seat is generally conical. The seat angles and the degree of angular mismatch between the piston and valve seat are varied between manufacturers and the applications for which the valves are designed.
One of main advantages of piston lift check valves is the fast closure response to reverse flow. Lift check valves are very sensitive to fluctuations in flow and offer an extremely

FIG 5

quick closure time. Due to the fact that they have very few moving parts (normally just the piston and in some cases a spring), wear due to impact and bearing loads is minimized. However, due to their quick closure time, lift check valves can be susceptible to repeated disk slam in pulsing flow applications, such as downstream of a positive displacement pump or compressor. This application has been addressed by the development of a “nonslamming” lift check valve design.
Generally, nonslamming lift check valves are designed with vents between the upper bonnet chamber and the downstream pressure by means of machined orifices through the upper guiding surface of the piston. These vents act to dampen the impact of the piston against the bonnet and the seat by increasing the response time to differential pressure reversals. The design of the vents are varied, some even utilizing miniature ball check valve in the piston vent orifices to provide slow piston movement in only one direction. The piston is sealed against the cage or body by very tight machining tolerances or by seal rings installed in machined grooves on the piston guiding surfaces. The purpose of the seal rings is to ensure controlled dissipation of fluid in the bonnet chamber through the piston orifices and the prevention of leak-by between the piston and the guiding surface.
The main disadvantages of piston lift check valves are small Cvs (large pressure drops for given flowrates), difficulty of maintenance and susceptibility to “sticking” in fluid systems containing particulates. The low Cv is caused by the tortuous flowpath through the valve body. These valves may also have higher cracking pressures due to the disk weight, especially in larger valve sizes. Additionally, any particulates in the system fluid can cause disk to become bound in the disk chamber due to the tight tolerances between the piston and the guiding surfac
4- Piston  Check Valve
A piston check valve, illustrated in Figure 6, is essentially a lift check valve. It has a dashpot consisting of a piston and cylinder that provides a cushioning effect during operation. Because of the similarity in design to lift check valves, the flow characteristics through a piston check valve are
essentially the same as through a lift check valve. Installation is the same as for a lift check in that the flow must enter from under the seat. Construction of the seat and disk of a piston check valve is the same as for lift check valves.
Piston check valves are used primarily in conjunction with globe and angle valves in piping systems experiencing very frequent changes in flow direction. Valves of this type are used on water, steam, and air systems.

FIG 6

5- Straight Through Poppet Type Lift Check Valves
The third type of lift check valve is the straight through poppet lift check valve. These valves are designed such that the disk is centered in the flow stream such that the full disk area is always available to the fluid pressure during both forward and reverse flow. The disk is attached to a “rod” which passes through guiding sleeves designed to provide alignment of the disk to the valve seats. A spring is installed on the downstream side of the disk to increase the closing speed during the initiation of reverse flow and to provide a slightly positive cracking pressure. The spring selection is analyzed for the particular valve application.

FIG 7

Poppet check valve designs range from the very simple and inexpensive foot valves (such as those used in vertical sump pumps in non-critical commercial applications), to the highly engineered “nozzle check valve” design. Poppet lift check valves are extremely good for fast closure applications due to their short disk travel, low minimum velocity and generally low disk mass. These attributes make poppet lift check valves especially good in systems were water hammer is a concern. Another advantage of this valve design is that the minimum required velocity is less than that of swing, tilting disk, piston lift and ball check valves.

FIG  8

Again, this is due to the disk being centered in the flow stream and the short travel distance of the disk to the full open position. Various seating materials are available for this valve design, including elastomer seats, polymeric seats and hardfacing. The main disadvantage of these valves is the difficulty of performing maintenance and the pressure drop associated with the valve design. Since poppet lift check valves are designed as a straight through unit, they have to be removed from the line to perform inspections and maintenance.

6- Butterfly Check Valves
Butterfly check valves have a seating arrangement similar to the seating arrangement of butterfly valves. Flow characteristics through these check valves are similar to the flow characteristics
through butterfly valves. Consequently, butterfly check valves are quite frequently used in systems using butterfly valves.
In addition, the construction of the butterfly check valve body is such that ample space is provided for unobstructed movement of the butterfly valve disk within the check valve body without the
necessity of installing spacers.
The butterfly check valve design is based on a flexible sealing member against the bore of the valve body at an angle of 45o.
The short distance the disk must move from full open to full closed inhibits the "slamming" action found in some other types of check valves. Figure 9  illustrates the internal assembly of the butterfly check valve.

FIG 9 

Because the flow characteristics are similar to the flow characteristics of butterfly valves, applications of these valves are much the same. Also, because of their relatively quiet operation they find application in heating, ventilation, and air conditioning systems. Simplicity of design also permits their construction in large diameters - up to 72 inches.
As with butterfly valves, the basic body design lends itself to the installation of seat liners constructed of many materials. This permits the construction of a corrosion-resistant valve at less expense than would be encountered if it were necessary to construct the entire body of the higher alloy or more expensive metal. This is particularly true in constructions such as those of titanium.
Flexible sealing members are available in Buna-N, Neoprene, Nordel, Hypalon, Viton, Tyon, Urethane, Butyl, Silicone, and TFE as standard, with other materials available on special order. The valve body essentially is a length of pipe that is fitted with flanges or has threaded, grooved, or plain ends. The interior is bored to a fine finish. The flanged end units can have liners of various metals or plastics installed depending upon the service requirements. Internals and fasteners are always of the same material as the liner.

7- Stop Check Valves
A stop check valve, illustrated in Figure 10, is a combination of a lift check valve and a globe valve. It has a stem which, when closed, prevents the disk from coming off the seat and provides a tight seal
(similar to a globe valve). When the stem is operated to the open position, the valve operates as a lift check. The stem is not connected to the disk and functions to close the valve tightly or to limit the travel of the valve disk in the open direction.

FIG 10

Dual Disk Check Valves
A dual disk check valve is actually a type of swing check valve that has been specially modified for piping systems where a low face-to-face profile is necessary due to constraints.

The dual disk design contains a disk hinge similar to that in a swing check valve. Two “half-circle” shaped disks are connected and hinged by a single “disk shaft” (analogous to a swing check valve’s hinge pin). The disk shaft is a hardened metal rod inserted through a bore in the body wall. A threaded retaining plug seals the body bore hole. Normally, two torsion springs are placed in contact with the two disks, with the disk shaft running through the inside diameter of the torsion springs. Each spring has two legs, one leg contacting each disk. The contact point between the disk and the spring is usually located beyond the centroids of the disks in order to minimize seat wear. As the disks move to the open position, the springs are placed in torsion. The purpose of the springs is to increase the closing speed and to provide a slight positive cracking pressure. Dual disk check valves normally incorporate a backstop into the valve design to prevent each disk from traveling more than 85° from the seated position. The purpose of limiting the travel is twofold:

FIG 11

· It ensures that enough of the downstream disk surface area is available to sense a reversal of flow, 

· It prevents one of the disks from opening more than 90° and being pinned open by the reverse flow.

Without a backstop, the valve may not close fast enough or at all. The disk travel limiting attribute of the dual disk design is either integral to the geometry of the disks or is performed by a backstop component, normally a shaft running through the body and placed such that interference occurs at a disk angle < 85°.

Valve Sizing
When choosing a check valve for a particular application, the flow of the system must be analyzed to determine the correct size and type of valve. There are two primary areas of concern when sizing a check valve:
- The pressure drop across the valve
- The minimum required velocity required to keep the disk in the full open position.
Pressure Drop Calculation Equations
The pressure drop across a check valve can be calculated by the following equations:

where :
Fp = piping geometry factor (dimensionless), obtained by calculation
K = resistance coefficient (dimensionless), obtained by manufacturer
m = mass flow rate (lb/sec), obtained by measurement
𝜌 = fluid density (lb/ft³), obtained by physical properties tables
d = inside pipe diameter (in), obtained by piping tables
w = mass flow rate (w = m x 3600) (lb/hr), obtained by calculation or measurement
Cv = flow coefficient (dimensionless), obtained by manufacturer
S = specific gravity of a liquid relative to water (dimensionless), obtained by physical properties table
q = volumetric flow rate (gpm), obtained by calculation

Minimum Velocity Calculation Equations
necessary to calculate the minimum required velocity for a specific valve to ensure that the valve will be fully open during operation. If system flow velocities are less than the minimum required velocity specified by the valve manufacturer for a specific valve size and model, stable operation of the valve will not be maintained. Excessive wear due to disk oscillations could result. The minimum required flow velocity is calculated by the following equation

where :
C = minimum required velocity constant (dimensionless), obtained by manufacturer
𝛖 = specific volume (ft³/lb), obtained by physical properties tables
The following calculation can be used to calculate the flow through a valve with a Cv
value obtained from the Vendor and a measured differential pressure:

Causes of Seat Leakage
Seat leakage can be the result of a number of adverse conditions. The most common are:
· Seat erosion due to cavitation, abrasive service or high velocity flow
· Corrosion of the seating elements
· Particulates or other seat contact obstructions
· Excessive wear/binding
· Misapplication, and
· Inadequate seat contact force

Advantages of Check Valves
They are self-actuated and require no external means to actuate the valve either to open or close. They are fast acting.
Disadvantages of Check Valves
The following are some of the disadvantages that are attributed to check valves:
1. Since all moving parts are enclosed, it is difficult to determine whether the valve is open or closed. Furthermore, the condition of internal parts cannot be assessed.
2. Each type of check valve has limitations on its installation configurations.
3. Valve disc can stick in open position.
Application of Check Valves

COMPARATIVE LIFE CYCLE COST ANALYSIS OF CENTRIFUGAL AND POSITIVE DISPLACEMENT PUMPS FOR MINE DEWATERING BY ALİ BURAK AKTAŞ

COMPARATIVE LIFE CYCLE COST ANALYSIS OF 
CENTRIFUGAL AND POSITIVE DISPLACEMENT PUMPS
 FOR MINE DEWATERING
BY
ALİ BURAK AKTAŞ



In mining activities, there is water flow to mining environment which must be removed by mine dewatering method to provide suitable working conditions. One of the ways of mine dewatering is conducted via pumps there mainly two types of pumps are being used in mine dewatering operations, centrifugal and positive displacement pumps. Centrifugal pumps utilize the submersible as feeder to horizontal pumps in main stations for further pumping to ponds or collection dams at surface, while positive displacement pumps utilize single stage piston diaphragm pumps to remove water collected at mine bottom. Decision making in both of these system needs to be made by considering overall cost components rather than focusing merely on initial investment cost. This can be made by applying life cycle cost analysis to both of the system.
Main objective of this study is to develop a basic decision support tool for selecting the most economic pump type. Research methodology followed in this research study entails literature survey regarding pump types and case scenario data to be used in economic analysis. Decision support tool was developed by integrating graphical user interfaces (GUI) so that pump selection could be made by decision makers. At the end, the program was tested by implementing a case study data. Results of the four years operation data in the program show that total net present cost of positive
displacement pump yields 828,389 $ USD less than centrifugal pump net present costs value despite of the fact that positive displacement pump has total investment 711,960 $ USD more than centrifugal pumps

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Liquid Ring Vacuum Pumps, Compressors and Systems Conventional and Hermetic Design H. Bannwarth

Liquid Ring Vacuum Pumps,
Compressors and Systems
Conventional and Hermetic Design
H. Bannwarth



Based on the very successful German editions, this English version has been thoroughly updated and revised to reflect the developments of the last years and the latest innovations in the field.
Throughout, the author makes excellent use of real-life examples and highly praised didactics to disseminate his expert knowledge needed by vacuum technology users and engineers in their daily work at industrial plants, as consultants or in design offices. He covers in detail the most modern liquid ring pumps, with chapters dedicated to maintenance, explosion prevention and general procedures for safety at work with this technology. The whole is backed by a large repository of frequently needed technical data, unit conversions, formulae and current industrial, technical and legal norms without drawing on unnecessary complex or theoretical mathematics.
The result is the ideal hands-on introduction to vacuum technology, ranging from fundamentals to in-depth expert knowledge on liquid-ring vacuum pumps.

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Crop protection equipment — Reciprocating positive displacement pumps and centrifugal pumps — Test methods BS ISO 12809:2011

Crop protection equipment
— Reciprocating positive
displacement pumps and
centrifugal pumps — Test methods
BS ISO 12809:2011

This International Standard specifies test methods and the environmental conditions for evaluating the performance of positive displacement pumps and centrifugal pumps designed for crop protection equipment.
It is not applicable to pesticide metering pumps for injection systems.

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Tribology of Hydraulic Pump Testing STP 1310

Tribology of Hydraulic
Pump Testing
STP 1310
George E. Totten, Gary H. Kling, 
and Donald J. Smolenski,
Editors

Traditionally, numerous tests have been used to determine the lubrication properties of hydraulic
fluids. These tests have included both pump tests and bench tests. However, none of these tests has achieved consensus acceptance within the fluid power industry. This lack ofconsensus has affected everyone in the industry.
Fluid users are confronted with a myriad of data obtained from different tests, if any at all,and almost all of the tests are conducted differently with no assurance that there is any correlation with specific types of wear that may be encountered in their hydraulic pumps.
Hydraulic pump OEMs (original equipment manufacturers) face a similar dilemma in that they are continually being asked to approve the use of new fluids on the basis of test data, if it exists, that may be conducted under conditions that may have no applicability to normal hydraulic pump usage or to their pumps.
Fluid suppliers are also confronted with obtaining lubrication data that illustrates that their fluids will exhibit the expected lubrication properties in every manufacturer's pumps of all designs and beating configurations and used in widely varying conditions, which are often severe. This problem is compounded by the fact that OEMs will not accept any test data except a use test in their own particular pump, often under unique evaluation conditions that may not
correlate to the acutal use conditions of the pump. Furthermore, it is impossible to evaluate
every fluid in every pump under numerous evaluation conditions.
Therefore, there is a need to develop a hydraulic fluid testing protocol that will provide the desired insights into the lubrication properties of hydraulic fluids in a widely varying array of pumps and use conditions. This testing protocol should provide the user a method of specifying fluids for particular uses and use conditions. The OEM should be able to apply the data obtained from standard tests to predict the lubrication properties that would be attained with different pumps, pressures, rotational speeds, wear surfaces, and bearings. Ideally, the fluid supplier should have available standard tests accepted by everyone in the industry that can be applied cost-effectively to determine fluid lubricity in hydraulic pumps and motors. Furthermore, these lubrication data could be correlatable to the expected performance in any manufacturer's pumps and use conditions.

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Petroleum, petrochemical and natural gas industries — Reciprocating positive displacement pumps ISO 13710

Petroleum, petrochemical and natural gas
industries — Reciprocating positive
displacement pumps
ISO
13710


This International Standard was developed from API Std 674, 2nd edition, 1995, with the intent that the 3rd edition of API Std 674 will be the same as this International Standard.
Users of this International Standard should be aware that further or differing requirements may be needed for individual applications. This International Standard is not intended to inhibit a vendor from offering, or the purchaser from accepting, alternative equipment or engineering solutions for the individual application. This may be particularly appropriate where there is innovative or developing technology. Where an alternative is offered, the vendor should identify any variations from this International Standard and provide details.
This International Standard requires the purchaser to specify certain details and features.
A bullet (•) at the beginning of a paragraph indicates that either a decision is required or further information is to be provided by the purchaser. This information should be shown on data sheets or stated in the enquiry or purchase order (see examples in Annex D). In this International Standard, where practical, US Customary (USC) units are included in brackets for information.
Annex A lists typical materials standards used in pumps.
Annex B contains a form in which are listed the vendor drawing and data requirements (VDDR).
Annex C specifies techniques for pulsation and vibration control.
Annex D contains typical data sheets.
Annex E describes pump system interaction and explains the differences between NPIP and NPSH.
Annex F contains an inspector's checklist.
Annex G specifies requirements for the lubrication system

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An Introduction To Positive Displacement Pump Types Selection and Applications

An Introduction To Positive Displacement Pump
Types  Selection and Applications


Introduction 
A Positive Displacement Pump has an expanding cavity on the suction side and a decreasing cavity on the discharge side. Liquid flows into the pumps as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. The volume is a constant given each cycle of operation.

Pump Types

PD pumps can be divided into two broad classifications, reciprocating and rotary. Figure 1 illustrates the classes, categories, and types of PD pumps utilized in the industry. The principles of both reciprocating and rotary type pumps, common terminologies of PD pump, and PD pump applications are discussed in the following sections

The positive displacement pumps can be divided in two main classes
              -  reciprocating
              -   rotary

FIG 1

The positive displacement principle applies whether the pump is a
        - rotary lobe pump
        - progressing cavity pump
        - rotary gear pump
        - piston pump
        - diaphragm pump
        - screw pump
        - gear pump
        - vane pump
        - regenerative (peripheral) pump
         - peristaltic

Reciprocating Pumps

Typical reciprocating pumps are
    - plunger pumps
    - diaphragm pumps

FIG 2

A reciprocating positive displacement pump is one in which a piston or plunger displaces a given volume of fluid for each stroke. The reciprocating pumps can also be categorized in different ways such as single acting or double acting; direct acting or indirect acting; and simplex or duplex. Reciprocating pumps are used in power plants for chemical feed system, fuel oil system, lubricating oil system, or hydrostatic pressure test.

FIG 3

In a diaphragm pump the plunger pressurizes hydraulic oil which is used to flex a diaphragm in the pumping cylinder. Diaphragm pumps are used to pump hazardous and toxic fluids.

Rotary Pumps

Rotary pumps operate in a circular motion and displace a constant amount of liquid with each revolution of the pump shaft. In general, this is accomplished by pumping elements moving in such a way as to expand volumes to allow liquid to enter the pump and discharge a smooth flow. Pumping element designs include gears, lobes, vanes, and screws . Rotary pumps are found in a wide range of applications due to their relatively compact design, high viscosity performance, continuous flow (regardless of differential pressure), and the ability to handle high differential pressure.

Gear Pumps

The most common type of rotary pump is the gear pump. In gear pumps, two or more gears mesh to provide the pumping action. The two main types of gear pumps are internal and external . Internal gear pumps carry fluid between the gear teeth from the inlet to outlet ports. External gear pumps carry fluid between the teeth and the casing.

FIG 4

Lobe Pumps

The lobe pump, shown on the right, receives its name from the rounded shape of the rotor radial surfaces, which permits the rotors to be continuously in contact with each other as they rotate. Fluid is carried between the rotor teeth and the pumping chamber

FIG 5

Vane Pumps

The vane pumps have movable sealing elements in the form of rigid blades, rollers, buckets, or slippers. The vanes work with a cam to draw fluid into and force it out of the pump chamber,

as shown.

FIG 6

Screw Pumps

Screw pumps carry fluid in the spaces between the screw threads. The fluid is displaced axially as the screw(s) mesh. Single screw pumps are commonly called progressive cavity pumps. They have a rotor with external threads and a stator with internal threads. The rotor threads are eccentric to the axis of rotation. Screw pumps are classified into single and multiple rotor types. Multiple rotor are the most common.

FIG 7

Pump Selection

The following factors are commonly considered for the selection of PD pumps vs. centrifugal  pumps:

· Self priming

· Abrasion resistance

· Control requirements

· Variation in flow

· Viscosity

· Fluid Density

· Corrosion

Additionally, the selection of pump class and type for a particular application is also influenced by factors such as system layout, intended life, energy cost, code requirements, and materials of construction. Figure 8  shows the differences between PD and centrifugal pumps in terms of performance, flow rate with various viscosity, and efficiency.

FIG 8

Common Characteristics of PD Pumps

Besides higher overall efficiency than centrifugal pumps (because internal losses are minimized), other common characteristics of PD pumps are:

1. Adaptable to high pressure operation

2. Variable flow rate through the pump is possible

3. Maximum throughputs are limited by mechanical considerations

4. Capable of efficient performance at extremely low volume throughput rates.

Pump and Head Terminology

The principle of conservation of energy states that the total energy input to a closed system is equal to the total energy output from that system. The energy in the fluid at Points 1 and 2 (as shown in Figure 9) can be restated by the following Bernoulli’s equation.

FIG 9

where: 

P₁, P₂ = Pressure at Points 1 and 2

ρ = Fluid Density

Z₁, Z₂ = Static Elevation at Points 1 and 2

V₁, V₂ = Velocity at Points 1 and 2

Ep = Energy Added by Pump

hf = Friction Loss Between Points 1 and 2

Fluid flow energy is often expressed as fluid “head” in units of feet. The following terminology applies to the Bernoulli’s equation.

· Pressure head, hp = P / ρ is the pressure energy

· Elevation head, he = Z, is the potential energy

· Velocity head, hv = V²/2𝙜 is the kinetic energy

· Pump head, Ep is the increase in fluid flow energy resulting from the pump work.

· Friction head, hf is the energy required to overcome the resistance to flow in the pipe, fittings, valves, entrances, and exits.

· Static suction head, hs is the vertical distance in feet above the centerline of the pump inlet to the free level of the fluid source.

· Static discharge head, hd is the vertical distance in feet above the pump centerline to the free level of the discharge tank.

· Net suction head, Hs is the total energy of the fluid entering the pump inlet.

· Total dynamic head, H is the net discharge head minus the net suction head. It is the amount of energy added to the fluid by the pump.

PD Pumps Calculations

The displacement is a function of the area of the liquid piston and the speed at which the piston is moving. The displacement of a single piston can be calculated from the formula

D= (A×n× s)/231

Where

 D = pump displacement, gallons per minute

A = area of the piston or plunger, inch²

n = rpm or strokes per minute of pump

s = stroke length, inches

231 = inch³/gal (conversion factor)

Brake horsepower for the pump is:

Where whp = water horsepower

Bhp = brake horsepower

Q = pump capacity, gpm

Pl = net liquid pressure, lb/in²

Em = mechanical efficiency (% as a decimal)

In a rotary pump the liquid displaced by each revolution of the pump is independent of the pump speed. The pump capacity, Q is equal to:

D = k Drp n – S

Where:

D= displacement capacity, gallons per minute

k = 0.004329, gallon/cubic inch (conversion factor)

Drp = rotary pump displacement, cubic inches per revolution

n = pump speed, revolutions per minute

S = pump slip, gallons per minute

Pump speed is the number of revolutions of the driving, or main, rotor per unit time. Pump pressure is the absolute pressure of the fluid at any location in the pump. Several pressure terms of interest are briefly discussed below.

·Velocity pressure Pv is the pressure caused by fluid velocity which mostly small relative to the total pressure and may be caused by the fluid velocity, which is typically small enough to be neglected.

·Outlet pressure Pd is the total pressure at the outlet of the pump. The outlet pressure is commonly expressed as the gage pressure which is the difference between the absolute pressure and atmospheric pressure at the outlet port.

·Inlet pressure Ps is the total pressure at the inlet to the pump. The pump differential pressure Ptd is the difference between the outlet pressure and the inlet pressure.

Ptd = Ps -Pd

Pump power is the total power required by the pump driver or the pump prime mover under given operating conditions. The pump power output can be computed by the following equations:

where:

whp = water horsepower which is equal to 550 ft lb/s

kW = kilowatt

Q = gallons per minute in whp equation or cubic meters per minute in kW equation

Ptd = pounds per square inch

Pump efficiency or pump mecha nical efficiency is the ratio of the rotary pump power output to the pump input. The difference between pump power input and output actually consists of three power losses represented by pump slip, mechanical friction in the pump, and fluid friction.