Capítulo II. Instalación y Operación de Caldera, Chiller y Cuarto Frio
2.2.11 Tubería de la recuperación parcial de calor
Equipment that is custom designed and engineered by the client and/or EPC to perform a project-specific function. Engineered equipment will typically
require more source inspection than non-engineered equipment. 4.106 Non-ferrous Materials
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4.107 Normalizing Heat Treatment
A heat treating process in which a ferrous material or alloy is heated to a specified temperature above the transformation range of the metal and subsequently cooled in still air at room temperature. Typically normalizing
heat treatments will refine the grain size and improve the impact properties of steels.
4.108 NPS
Nominal Pipe Size—A standard for designating pipe sizes (inches) and
associated wall thickness (schedule) e.g. the nominal pipe size for a four inch pipe is normally shown as NPS 4.
4.109 NPSHa
NPSH determined by the purchaser for the pumping system with the liquid at (1) the rated flow and (2) normal pumping temperature.
4.110 NPSHr
NPSH that results in a 3% loss of head (first-stage head in a multistage pump) determined by the vendor by testing with water.
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4.111 Normal Operating Condition
The condition at which usual operation is expected and optimum efficiency is desired. This condition is usually the point at which the vendor certifies that performance is within the tolerances stated in this standard.
4.112 Normal Operating Point
Point at which usual operation is expected and optimum efficiency is desired. This point is usually the point at which the vendor certifies the heat rate is
within the tolerances stated in this standard.
4.113 Normal Transmitted Power
The power at which usual operation is expected and optimum efficiency is desired. The normal transmitted power may be equal to or less than the gear- rated power.
4.114 Nozzles
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4.115 Oil Mist Lubrication
Lubrication provided by oil mist produced by atomization and transported to the bearing housing, or housings, by compressed air.
4.116 Observed Inspection (Observed test) (non-hold point?)
Inspection or test where the purchaser is notified of the timing of the inspection or test and the inspection or test is performed as scheduled, regardless of whether the purchaser or his representative is present.
4.117 Open Cycle
One which the working medium enters the gas turbine from the atmosphere and discharges to the atmosphere directly or indirectly through exhaust heat recovery equipment.
4.118 Operating Region
Portion of a pump's hydraulic coverage over which the pump operates.
4.119 Overhung Pump
Pump whose impeller is supported by a cantilever shaft from its bearing assembly.
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Overhung Pump
The impeller(s) is mounted on the end of a shaft which is cantilevered or “overhung” from its bearing supports.
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Charlie Chong/ Fion Zhang 4.120 P
The chemical symbol for phosphorus which may appear on an MTR.
4.121 Peak to Peak Value
The difference between positive and negative extreme values of an electronic signal or dynamic motion.
4.122 Pinion
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4.123 Piston Rod Drop
A measurement of the position of the piston rod relative to the measurement probe mounting location(s) (typically oriented vertically at the pressure
Charlie Chong/ Fion Zhang Rod Drop
The vast majority of Reciprocating Compressors are designed with horizontal Cylinders and Pistons. This is primarily due to foundation requirements and the popularity of opposed- balanced machine designs.
The force of gravity causes the Piston to "RIDE" more in the bottom of the Cylinder than in the top. In turn, this causes the Piston to wear more in the "DOWN" direction. Machine
manufactures provide wear or rider rings to provide a replaceable wearing surface. For lubricated Cylinders, glass embedded Teflon may be used. For non-lubricated Cylinders, Teflon may be used.
The wear or rider rings are allowed to wear sacrificially. They are rotated or replaced before
damage to the Cylinder lining occurs. There are several methods used to determine when to replace or rotate the rings. One method is to operate a new machine for a given number of hours or days. Then a valve is removed, and the wear is measured by using a feeler gauge. A calculation is then performed with this information. The results determine the length of time the machine can be safely operated with periodic inspections of the rings. Obviously, this is a very frustrating method of performing preventative maintenance.
Currently, one popular safety device for detecting Rod Drop is a unit mounted under the rod at a gap determined by the allowable wear of the wear ring. When the rod contacts the safety unit white metal is worn through allowing instrument air to escape. This in turn causes a
pneumatic flag on the control panel to change status.
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There are several disadvantages to the above-mentioned methods of Rod Drop detection:
1. A real trend of ring wear cannot be established with a short amount of operating time.
2. Since the machine must be shut down, halting production, periodic inspections for ring wear are expensive.
3. A change in processed gas, load changes, and foreign matter can cause an extreme change in ring wear rate.
For several years, Eddy Probe systems have been utilized to measure Rod Drop. This method of Rod Drop measurement has been gaining positive recognition with
Reciprocating Machine users. This is especially true on larger machines, or when the customer has become frustrated with the previously mentioned methods.
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To measure Rod Drop with an Eddy Probe system, the probe is installed in the vertical direction viewing the rod. The preferred installation would have a probe bracket adapted to the packing gland plate, mounted internal to the distance piece. As an alternate solution, some users have used the CMCP801 Eddy Probe Housing, providing an external adjustment (through the distance piece) of the probe gap. As the Eddy Current field emitted from the probe tip will penetrate the rod surface 15 mils, it is important that the observed rod be homogenous in nature and free of any surface irregularities. The Eddy Probe system is interfaced to a CMCP545 Position
Transmitter to measure the probes DC output (Probe Gap). The CMCP545 will provide a 4-20 mA output that is proportional to the DC Gap Voltage. If a CMCP545A Monitor is used, two levels of alarms with corresponding Alert and Danger relays are provided. By trending the DC Gap
voltages from the eddy probe, it is possible to measure the average horizontal running position of the piston rod. This method of Rod Drop measurement offers advantages over the previously described methods:
1. An immediate trend of ring wear can be established.
2. The periodic inspections that require a machine shutdown and disassembly are eliminated. 3. Wear rate changes can be observed.
4. Both Warning and Shutdown alarms can be provided.
Monitoring the Rod Drop of a Reciprocating Machine using an Eddy Probe offers the following benefits:
1. Prevents Cylinder and Piston damage caused by the Piston contacting the liner.
2. Stops unnecessary periodic inspections that require a machine shutdown with the associated lost process time.
1. Scheduling down time to replace or rotate wear rings within the limitations of a plant's schedule.
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4.124 Piston Rod Runout
The change in position of the piston rod in either the vertical or horizontal direction as measured at a single point (typically at or near the pressure
packing case) while the piston rod is moved through the outbound portion of its stroke.
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Rod Run Out
Whereas Rod Drop is a measurement of rod position, Rod Run Out is a
measurement of the rod's actual dynamic motion as it travels back and forth on its stroke. Another term for this measurement is Rod Deflection.
One method to make this measurement is to mount a dial indicator in the
distance piece riding on the piston rod. The machine is then barred through a complete cycle. Indicator readings are taken in both the vertical and
horizontal directions during the machine's cycle.
The amount of Rod Run Out is highly dependent on the cylinder alignment with the Crosshead. Due to inherent looseness in the Crosshead and thermal growth of the machine, higher readings of Rod Run Out are allowed in the vertical direction. The horizontal direction allowances are much less and high readings are attributed to misalignment. Typical Rod Run Out allowances are 3.5 to 6.0 mils Pk-Pk in the vertical direction and 1.5 to 2.0 mils Pk-Pk in the horizontal direction.
Comments:
Angular misalignment?
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An alternative to dial indicators to make this measurement is again an Eddy Probe
System. Since dial indicators can only be used while the machine is being barred, they do not provide an accurate measurement of Rod Run Out. On the other hand, Eddy Probes can make this measurement while the machine is operating. This provides a highly accurate measurement of the actual dynamic motion of the rod under full load conditions.
Eddy Probes for Rod Run Out measurement are typically used on "Hyper
Compressors". These are reciprocating compressors used for very high compression ratios up to 60,000 PSI discharge pressure. To withstand the high pressures, the
gland seals on these machines are quite complex and small amounts of Rod Run Out will cause these gland seals to fail with severe consequences.
Hyper Compressor Piston Rods are manufactured of Tungsten Carbide. Tungsten Carbide is a very hard material (Rockwell C values of approximately 84): will handle enormous compressive loads, but is much weaker when subjected to tension of
flexing. Either a gland seal or Piston Rod failure in a Hyper Compressor will have harsh consequences.
Utilizing the AC component (dynamic motion) of an Eddy Probe signal, one eddy
probe is mounted in the vertical (x) axis and one is mounted in the horizontal (Y) axis in relation to the Piston Rod. Each Eddy Probe is interfaced to a CMCP540A Vibration (Displacement) Monitor for signal conditioning, alarming and interface to a PLC or
DCS.
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The vertical Eddy Probe can also be used as for Rod Drop measurements. Therefore, the installation of X and Y Eddy Probes can be used for both Rod Run Out and Rod Drop measurements.
This method of Rod Run Out measurement offers advantages over the dial indicator method:
1. The measurement is taken all the time.
2. The measurement is taken while the machine is operating under load and at temperature.
3. Alarms are provided for early indication of problems and machine shutdown if desired.
Monitoring the Rod Run Out of a Reciprocating Machine using X, Y Eddy Probes offers the following benefits:
1. An assurance that Rod Run Out is within tolerable limits after the machine is at operating speed and temperature.
2. An early warning of gland seal failure caused by excessive Rod Run Out. 3. Machine shutdowns for repairs can be scheduled
4. To reduce effects on plant production.
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4.125 Potential Maximum Power
Expected power capability when the gas turbine is operated at maximum
allowable firing temperature, rated speed or under other limiting conditions as defined by the manufacturer and within the range of specified site values.
4.126 PQR
Procedure Qualification Record per ASME BPVC Section IX, QW 200.2.
4.127 Predicted Capacity Limit T
he maximum volume flow capacity at the end of curve line which defines the manufacturer’s capability to reasonably predict performance. This may or may not be an actual choke limit.
4.128 Preferred Operating Region
Portion of a pump's hydraulic coverage over which the pump's vibration is within the base limit of this International Standard.
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4.129 Pressure Casing
Composite of all stationary pressure-containing parts of the pump, including
all nozzles, seal glands, seal chambers and auxiliary connections but
excluding the stationary and rotating members of mechanical seals. 4.130 Procedure
A document detailing how a work process is to be performed e.g. a welding procedure.
4.131 Projection
A nozzle or attachment projection is the length from the nozzle or the attachment face to the vessel shell centerline.
4.132 Protractor
An instrument for measuring angles, typically in the form of a flat semicircle marked with degrees along the curved edge.
Charlie Chong/ Fion Zhang Protractor
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4.133 Proximity Probe
A non-contacting sensor that consists of a tip, a probe body, an integral coaxial or triaxial cable, and a connector and is used to translate distance (gap) to voltage when used in conjunction with an oscillator-demodulator.
4.134 RV/PRD/PSV
Pressure Relief Valve/Pressure Relief Device/Pressure Safety Valve.
4.135 PT
Penetrant Testing (Examination).
4.136 QA
Quality Assurance—A proactive quality process that aims to prevent defects and refers to a program of planned, systematic and preventative activities implemented in a quality system that is intended to provide a degree of
confidence that a product will consistently meet specifications. It includes the systematic measurement, comparison with a standard, monitoring of
processes and an associated feedback loop that is intended to avoid deviations from specification.
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Proximity Probe
Charlie Chong/ Fion Zhang 4.139 QC
Quality Control— The specific steps in a QA process that aim to find
potential defects in a product before it is released for delivery e.g. VT, PT, RT, UT, dimensional verification, etc. The QA process will specify the particular QC steps necessary during manufacture/fabrication of a product.
4.140 Qualification
Demonstrated skill, demonstrated knowledge, documented training, and documented experience required for personnel to perform the duties of a specific job e.g. a certified source inspector.
4.141 Quality Surveillance
The process of monitoring or observing the inspection activities associated with materials, equipment and/or components for adherence to the specific procedure, product specification, code or standard specified in the contractual requirements. For the purposes of this guide, quality surveillance and source inspection mean the same thing (see definition for source inspection).
4.142 Quenching
Rapid cooling of a heated metal for the purpose of affecting mechanical and/or physical properties.
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4.143 Radially Split
Split with the principal joint perpendicular to the shaft center-line.
4.144 Rated Input Speed of Gear Unit
The specified (or nominal) rated speed of its driver, as designated by the purchaser on the data sheets.
4.145 Rated Output Speed of Gear Unit
The specified (or nominal) rated speed of its driven equipment, as designated by the purchaser on the data sheets.
4.146 Rated Operating Point
Point at which the vendor certifies that pump performance is within the tolerances stated in this International Standard.
4.147 Rated Power
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4.148 Rated Speed/ 100% Speed
Highest speed (revolutions per minute) of the gas turbine out-put shaft
required of any of the operating conditions for the driven equipment and at which site rated power is developed.
4.149 RMS
Root Mean Square—A measure of surface finish on flanges.
4.150 Rotor
Assembly of all the rotating parts of a centrifugal pump.
4.151 RT
Radiographic Testing (Examination).
4.152 Rust Bloom
The term used to describe surface discoloration that occurs on the surface of steel that has been previously blasted e.g. near-white or white metal in
preparation for coating. When rust bloom is found, the surface should
Charlie Chong/ Fion Zhang 4.153 S
The chemical symbol for sulfur which may appear on an MTR.
4.154 SDO
Standards Development Organization e.g. API, ASME, ASTM, NACE, MSS, TEMA, etc.
4.155 Seal Buffer gas
Clean gas supplied to the high-pressure side of a seal.
4.156 Seal Chamber
Component, either integral with or separate from the pump case (housing), which forms the region between the shaft and casing into which the seal is installed.
4.157 Seal Gas
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4.158 Seal Gas Leakage
Gas that flows from the high-pressure side of the seal to the low-pressure side of the seal.
4.159 Shutdown Set Point
Preset value of a measured parameter at which automatic or manual shutdown of the system or equipment is required.
4.160 SI
Source Inspector or Source Inspection.
4.161 SME
Subject Matter Expert.
4.162 Sole Plates
Grouted plates installed under motors, bearing pedestals, gear-boxes, turbine feet, cylinder supports, crosshead pedestals and compressor frames.
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Charlie Chong/ Fion Zhang Sole Plate
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4.163 Solution Anneal Heat Treatment
Heating an alloy to a specified temperature, holding at the temperature long enough for one or more elements to reenter into solid solution and then
cooling rapidly (?) enough to hold those elements in solid solution.
Comment:
Stainless steel only
4.164 SOR
Supplier Observation Reports—Documents filled out by the SI indicating
concerns or other factual descriptions of what was noticed during the course of product surveillance, but not necessarily issues that may be considered defects or requiring NCR’s.
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Solution Annealing Heat Treatment Process
Many stainless steel castings require either solution annealing or homogenizing after the casting process.
Homogenization is commonly used on precipitation hardening stainless steels like 17-4 and 15-5 to resolve alloy segregation and dendritic structures and homogenize the chemical composition and microstructure. The temperature ranges for this process are often in excess of 2000F.
Solution Annealing stainless steel castings is a process which takes the carbides that have precipitated in the grain boundaries and dissolves then into the surrounding matrix. The austenitic stainless steel castings are typically solution annealed at temperatures between 1900F to 2100F and rapidly cooled to prevent a repeat of carbide precipitation in the grain
boundaries. Some alloys due to their low carbon content do not need a
solution anneal due to carbide formation, but benefit from a solution anneal to achieve maximum corrosion resistance.
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Stainless Steel - Heat Treatment
Introduction
Stainless steels are generally heat-treated based on the stainless steel type and reasons for carrying out the treatment. Heat treatment methods, such as stress
relieving, hardening and annealing, strengthen the ductility and corrosion resistance properties of the metal that is modified during fabrication, or generate hard structures capable of tolerating abrasion and high mechanical stresses.
Heat treatment of stainless steels is mostly carried out under controlled conditions to avoid carburization, decarburization and scaling on the metal surface.
Annealing
Annealing, or solution treatment, is employed for recrystallizing the work-hardened austenitic stainless steels and drawing chromium carbides, precipitated around the work-hardened stainless steels, into the solution. In addition, this treatment removes stresses occurred during sold-working, and homogenizes dendritic stainless steel welds.
Annealing of stainless steels is carried out at temperatures greater than 1040°C, but certain types of steel can be annealed at very controlled temperatures of below