Process Engineering Equipment Handbook Episode 2 Part 2 pot

resistance to the magnetic flux generated from the magnet. This gap resistance decreases as the reed blades come closer together. The magnetic force produced by permanent magnets or electromagnets is inversely proportional to the square of this distance gap. Therefore, the reed-switch-blade closure will accelerate as the tips approach each other. The larger the magnetic field, the faster the blades snap together. (See Fig. C-417.) Control Valves A number of process valves are simple hand-turned valves. They include: Globe valves: Fluid flow through this valve changes direction. Fewer turns are required to move this valve than with a gate valve. It is useful for throttling service. If extremely close regulation is required, a needle globe valve should be used. Ball valves require a 90° turn to shut off flow completely. They are much lighter for a given size than either a globe or a gate valve. Maintenance is simple; however, this valve type is not suitable for throttling. Plug valves can be either lubricated or nonlubricated. They are like ball valves, except instead of the ball there is a plug, often shaped like a truncated cone. These valves do not seize or gall as might be the case with some gate valves. Diaphragm valves have a flexible diaphragm that closes the pipe against the flow of the liquid. Isolation of the working parts from the fluid stream prevents product contamination and corrosion. Maintenance requires the occasional diaphragm change. Pinch valves are more for laboratory-type application as they stop flow through small-diameter rubber tubing. Some valves operate either manually or automatically. Controls, Retrofit C-391 FIG. C-414 Reed switch. (Source: Demag Delaval.) FIG. C-415 Single-pole–single-throw (SPST) reed switch. (Source: Demag Delaval.) FIG. C-416 Single-pole–double-throw (SPDT) reed switch. (Source: Demag Delaval.) FIG. C-417 Magnetic activation of reed switch. (Source: Demag Delaval.) resistance to the magnetic flux generated from the magnet. This gap resistance decreases as the reed blades come closer together. The magnetic force produced by permanent magnets or electromagnets is inversely proportional to the square of this distance gap. Therefore, the reed-switch-blade closure will accelerate as the tips approach each other. The larger the magnetic field, the faster the blades snap together. (See Fig. C-417.) Control Valves A number of process valves are simple hand-turned valves. They include: Globe valves: Fluid flow through this valve changes direction. Fewer turns are required to move this valve than with a gate valve. It is useful for throttling service. If extremely close regulation is required, a needle globe valve should be used. Ball valves require a 90° turn to shut off flow completely. They are much lighter for a given size than either a globe or a gate valve. Maintenance is simple; however, this valve type is not suitable for throttling. Plug valves can be either lubricated or nonlubricated. They are like ball valves, except instead of the ball there is a plug, often shaped like a truncated cone. These valves do not seize or gall as might be the case with some gate valves. Diaphragm valves have a flexible diaphragm that closes the pipe against the flow of the liquid. Isolation of the working parts from the fluid stream prevents product contamination and corrosion. Maintenance requires the occasional diaphragm change. Pinch valves are more for laboratory-type application as they stop flow through small-diameter rubber tubing. Some valves operate either manually or automatically. Controls, Retrofit C-391 FIG. C-414 Reed switch. (Source: Demag Delaval.) FIG. C-415 Single-pole–single-throw (SPST) reed switch. (Source: Demag Delaval.) FIG. C-416 Single-pole–double-throw (SPDT) reed switch. (Source: Demag Delaval.) FIG. C-417 Magnetic activation of reed switch. (Source: Demag Delaval.) Butterfly valves operate with the movement of a wing-like disk that works at right angles to the fluid flow. This valve type can be operated manually or using pneumatic, electrical, hydraulic, or electronic actuation. Nonreturn or check valves prevent the reversal of flow in piping. In a swing check type the hinged disk is held open with the flow of liquid. When flow stops, gravity causes the disk to fall into closed position. With lift check–type valves, the closure disk is raised by the fluid flow. When flow stops, the disk falls back into closed position. Current-to-Pressure Converters for Precise Steam and Fuel Valve Control* The source for the information in this subsection is Voith Turcon who designate their current-to-pressure converters “I/P” (“I” for current and “P” for pressure). I/P converters offer control of steam and fuel valve actuators. Although designed for turbine applications, these converters can also be effective in other process control situations. This converter quickly and precisely changes a current input signal into a proportional fluid output pressure to regulate steam or fuel flow. I/P converters are built to a solid, compact design. All of the control electronics are safely housed within the unit for reliable functioning—even in harsh environments. With just three moving parts, this I/P converter is reliable and durable (“low-wear”). (See Figs. C-418 through C-421 and Table C-33.) Operating principles The I/P converter reliably converts a 4–20 mA input signal into a proportional output hydraulic pressure and double-checks for supremely accurate valve positions and turbine speeds. At the core of the I/P converter is an electromagnet. A 24-volt DC current energizes the magnet, which in turn creates a force on the actuating rod. A 4– 20 mA input signal works with the unit’s controller and amplifier to regulate this force. Any variation in the 4–20 mA input signal affects the pressure being exerted by the magnet onto the actuating rod. The force applied to the actuating rod is used to precisely control a hydraulic piston, which opens and closes the consumer and drain ports. (See Figs. C-422 through C-425.) The sequence of operations is as follows: 1. When the 4–20 mA signal reaches the converter, its controller and amplifier adjust the magnetic force to a pressure directly proportional to the input signal. 2. This force is measured by a semiconductor that serves as the unit’s magnetic force sensor/flux detector. Magnetic force lines penetrating this element produce a proportional output voltage (the Hall effect). 3. The output voltage is looped back to the converter’s controller and compared to the set value, W. If the unit senses a difference between the input signal and the feedback signal, the controller and amplifier correct the magnetic force so that the difference is zero. 4. The magnetic force adjusts the actuating rod to the appropriate position with up to 90 lb (400 N) of pressure. 5. As a result of this precise control technology, the I/P converter’s output line always contains the exact pressure needed to position the steam or fuel valve. C-392 Controls, Retrofit *Source: J.M. Voith GmbH, Germany. Controls, Retrofit C-393 FIG. C-418 “I/P” converters. (Source: J.M. Voith GmbH.) FIG. C-419 A typical installation of an I/P converter in a cogeneration plant. (Source: J.M. Voith GmbH.) C-394 Controls, Retrofit FIG. C-420 Minimum and maximum output pressures of an I/P converter can be set externally. (Source: J.M. Voith GmbH.) TABLE C-33 Selection Table Manual Piston Maximum Flow Rate Flow Rate Regulating Actuation Damping I/P Converter Type Input to Consumer to Drain Range With Without With Without Standard EExd Pressure (Dp = 1 bar) (Dp = 1 bar) 0–72.5psi ᭿᭿DSG-B05102 DSG-B05202 101.5psi 4.9GPM 5.4GPM 0–5 bar ᭿᭿DSG-B05112 DSG-B05212 7 bar 18.6l/min 20.5l/min ᭿᭿ DSG-B05103 DSG-B05203 ᭿᭿DSG-B05113 DSG-B05213 14.5–101.5psi ᭿᭿DSG-B07102 DSG-B07202 101.5psi 4.9GPM 5.4GPM 1–7bar ᭿᭿DSG-B07112 DSG-B07212 7 bar 18.6l/min 20.5l/min ᭿᭿ DSG-B07103 DSG-B07203 ᭿᭿DSG-B07113 DSG-B07213 0–145psi ᭿᭿DSG-B10102 DSG-B10202 219psi 4.4GPM 4.9GPM 0–10 bar ᭿᭿DSG-B10112 DSG-B10212 15 bar 16.8l/min 18.8l/min ᭿᭿ DSG-B10103 DSG-B10203 ᭿᭿DSG-B10113 DSG-B10213 14.5–203psi ᭿᭿DSG-B14102 DSG-B14202 219psi 4.4GPM 4.9GPM 1–14 bar ᭿᭿DSG-B14112 DSG-B14212 15 bar 16.8l/min 18.8l/min ᭿᭿ DSG-B14103 DSG-B14203 ᭿᭿DSG-B14113 DSG-B14213 0–290psi ᭿᭿DSG-B20102 DSG-B20202 655psi 2.5GPM 2.1GPM 0–20 bar ᭿᭿DSG-B20112 DSG-B20212 45 bar 9.8l/min 12.0l/min ᭿᭿ DSG-B20103 DSG-B20203 ᭿᭿DSG-B20113 DSG-B20213 0–430psi ᭿᭿DSG-B30102 DSG-B30202 430psi 5.4GPM 5.8GPM 0–30 bar ᭿᭿DSG-B30112 DSG-B30212 30 bar 20.5l/min 22.3l/min ᭿᭿ DSG-B30103 DSG-B30203 ᭿᭿DSG-B30113 DSG-B30213 NOTES 1. Further pressure ranges available upon request. 2. Consult factory for FM-certified explosion-proof designs which meet Class I, Divisions 1 and 2, Groups B, C, and D service. 3. I/P converter weight: approximately 22 lb (10 kg) for all models. FIG. C-421 Applications of an I/P converter. (Source: J.M. Voith GmbH.) C-395 C-396 Controls, Retrofit FIG. C-422 Internals of a typical I/P converter. (Source: J.M. Voith GmbH.) Controls, Retrofit C-397 FIG. C-423 Typical dimensions of an I/P converter. (Source: J.M. Voith GmbH.) FIG. C-424 I/P converter uses industry standard connections. (Source: J.M. Voith GmbH.) FIG. C-425 Schematic of I/P converter connections. (Source: J.M. Voith GmbH.) Advantages of this basic design ᭿ The unit’s magnetic drive and the hydraulic section’s pressure-reducing valve work together to function as a pressure-regulating valve. ᭿ Dynamic and hysteresis-free ᭿ Resolution is better than 0.1 percent ᭿ Accuracy is not affected by air-gap, magnetic hysteresis, temperature, or fluctuations in supply voltage. ᭿ Recommended oil contamination to NAS 1638 Class 7, or ISO 4406 Class 16/13. ᭿ Short conversion time from mA input signal to proportional, stationary pressure (t < 35 m). ᭿ Few electronic and mechanical parts ensure full functionality in harsh environments. ᭿ All electronics for the I/P converter are integrated in the housing. ᭿ Design withstands higher input pressure (pressure ranges available from 0 to 3000 psi). ᭿ Standard and explosion-proof designs are available. (See Figs. C-426 and C-427.) ᭿ In the version incorporating a PID controller, you can compensate for pipeline pressure losses. This optional design also allows for control of valve positions and turbine rpm. ᭿ Uses turbine oil as hydraulic fluid with no additional filter required. C-398 Controls, Retrofit FIG. C-426 Explosion-proof design (for EExD IIC T4, PTB No Ex-90, C, 1065). (Source: J.M. Voith GmbH.) [...]... Applies to this OEM’s models AHP- (1 ,20 0XP, 1 ,20 0XPHC, 1,801XP, 1,801XPHC)] UL/CSA Standards UL-1604 UL-1995 CSA 22 .2 Hazardous duty operation, Class I and II Division 2, Class III Div 1 and 2 Tested thru ETL and ETLc Testing Laboratories, Report # 5 320 15 Applies to models AHP- (1 ,20 0XP, 1 ,20 0XPHC, 1,801XP, 1,801XPHC) Heating & Cooling Equipment, Categories 169 & 29 4, No 23 6-M90 Tested thru ETL and ETLc... ambient (outside) air temperature ✍ (9/5 ¥ °C) + 32 = °F or 5/9 (°F - 32) = °C Determine the maximum allowable enclosure air temperature Determine temperature differential (Step 2 - Step 1) ✍ 9/5 ¥ D °C = D °F or 5/9 ¥ D °F = D °C Determine exposed surface area = 2( H ¥ W) + 2( H ¥ D) + 2( W ¥ D) ✍ (Exclude nonexposed surfaces) 1 m2 = 10.76 ft2, or 1 ft2 = 0 929 m2 Estimate ambient load (example uses 1-in insulation;... improved COP C- 422 Cooling; Cool, Products That (Air Conditioners); Liquid-Cooled Air Conditioners TABLE C-36 Air Conditioner Sizing To size an air conditioner proceed with the following 7 steps A free-standing enclosure (3¢ ¥ 3¢ ¥ 2 ) with 1≤ insulation has been provided as an example English Step 1 (Ta) 2 3 (Te) (DT) 4 (Sa) 5 (Qa) 6 (Qe) Metric + 120 °F +50°C +100°F -20 °F +38°C - 12 C 42 ft2 3.9 m2 140 Btu/h... Administration (FHSA) None None Ethylene Glycol “Hazardous Air Pollutant” 42 U.S.C § 74 12 (b) “Hazardous Substance” HAPs from 1990 CAAA are included into 42 U.S.C § 9601 (14) “Toxic Chemical” 42 U.S.C § 11 023 42 C.F.R § 3 72. 65 Health Advisory Issued 50 ppm PEL 29 C.F.R § 1910.1000 50 ppm TLV “Warning, Harmful or Fatal if Swallowed” 16 C.F.R § 1500.1 32 Adjustable speed vacuum pumps replaced the constant speed milking... Laboratories, Report # 5 320 15 Applies to models AHP- (1 ,20 0, 1 ,20 1, 1 ,20 0HC, 1 ,20 1HC, 1 ,20 0X, 1 ,20 0XHC, 1,801, 1,801X, 1,801XHC, 1,801HC) Reliability and mean time between failure (MTBF) The life expectancy of a thermoelectric device is high due to its solid-state construction Service life is typically in excess of five (5) years, under normal conditions MTBFs on the order of 2 300,000 h at room temperature,... environment Military Standards Mil-Std 810 Corrosion (Salt Fog Testing) Method 509 .2, 168 Hours, Employed for all NEMA-4X units Vibration Method 514.3, 2 hours, x, y, z axis 8.9 G’s, 10 2, 000 Hz with a magnitude of 0.04 G2/Hz, Employed for all XM- Versions, Standard models are designed to withstand 2. 2 G’s Shock Method 516 .2, with 30 G’s peak amplitude, 11 ms pulse duration, half-sine waveform, and three... Performance and frequency response See Figs C- 428 and C- 429 Knife-gate valve* Depending on what flows through (process) pipe, the cause of costliest wear on one line could be heat or corrosion, while abrasiveness is the key concern in another * Source: Adapted from extracts from “Controlling the Flow,” Mechanical Engineering, ASME, December 1998 FIG C- 428 Performance and frequency response curves for... from deteriorating in Hawaii’s tropical climate (Source: Mechanical Engineering Power, ASME, November 1997.) NEC (Source: NEC 1993, Article 500, 70-466 to 70-471) CID2 Groups (A–D) Class 1, Division 2 (Hazardous Environments) A Class 1, Division 2 location is a location (1) in which volatile flammable liquids or flammable gases are handled, processed, or used, but in which the liquids, vapors, or gases will... Co.) system Each mining, power, or paper company has to choose parts for its pipeline that offer the best balance of performance characteristics for its particular load Knife-gate valves control the flow in many process piping systems Mining companies use piping systems to transport newly mined minerals, such as gold, ore, and coal, to processing plants The excavated materials are crushed and suspended... some example application illustrations Typical design environment (NEMA, Mil-Std, NED, UL/CSA) specifications* (see Figs C-438 through C-441) Typical NEMA (Source: NEMA Publication No 25 0, Part 1, Page 1) NEMA- 12 Type 12 enclosures are intended for indoor use primarily to provide a degree of protection against dust, falling dirt, and dripping noncorrosive liquids Type 4X enclosures are intended for . DSG-B1 420 3 ᭿᭿DSG-B14113 DSG-B1 421 3 0 29 0psi ᭿᭿DSG-B201 02 DSG-B2 020 2 655psi 2. 5GPM 2. 1GPM 0 20 bar ᭿᭿DSG-B201 12 DSG-B2 021 2 45 bar 9.8l/min 12. 0l/min ᭿᭿ DSG-B20103 DSG-B2 020 3 ᭿᭿DSG-B20113 DSG-B2 021 3 0–430psi. ᭿᭿DSG-B101 12 DSG-B1 021 2 15 bar 16.8l/min 18.8l/min ᭿᭿ DSG-B10103 DSG-B1 020 3 ᭿᭿DSG-B10113 DSG-B1 021 3 14.5 20 3psi ᭿᭿DSG-B141 02 DSG-B1 420 2 21 9psi 4.4GPM 4.9GPM 1–14 bar ᭿᭿DSG-B141 12 DSG-B1 421 2 15 bar. ᭿᭿DSG-B071 02 DSG-B0 720 2 101.5psi 4.9GPM 5.4GPM 1–7bar ᭿᭿DSG-B071 12 DSG-B0 721 2 7 bar 18.6l/min 20 .5l/min ᭿᭿ DSG-B07103 DSG-B0 720 3 ᭿᭿DSG-B07113 DSG-B0 721 3 0–145psi ᭿᭿DSG-B101 02 DSG-B1 020 2 21 9psi 4.4GPM