Mounting and Operating Instructions EB 9520 EN. Differential Pressure and Flow Meter Media 05

Transcription

1 Differential Pressure and Flow Meter Media 5 Fig. 1 Media 5, indicating unit with differential pressure cell, on the right with valve block and pressure gauge Mounting and Operating Instructions EB 952 EN Edition April 24

2 Contents Contents Page 1 Design and principle of operation Installation Arrangement of instruments for liquid level measurement Arrangement of instruments for flow rate measurement Media 5 indicating unit Differential pressure lines Orifice plate assembly Accessories Valve block Shut-off and equalizing valves Equalizing tanks Accessories for connection Start-up Flow rate measurement Liquid level measurement Operation Zero adjustment Draining Adjusting and modifying the measuring range Version with limit switches Electrical connection Adjusting the alarm contacts Retrofitting/replacing the contact unit Dimensions in mm Note! Devices intended for oxygen service are labeled "Oxygen! Keep free of oil and grease!" These versions are cleaned and assembled by the manufacturer under special conditions. Appropriate gloves need be worn on replacing parts that come in contact with oxygen, e.g. measuring springs. When returning devices designed for oxygen service the manufacturer for repair, the sender assumes full responsibility that the handling of the devices be repaired meets the requirements specified in VBG 62 or equivalent regulations until the devices are handed over the manufacturer. Otherwise, SAMSON AG will not accept any responsibility. 2 EB 952 EN

3 Safety instructions Assembly, start-up and operation of the device may only be performed by trained and experienced personnel familiar with this product. According these mounting and operating instructions, trained personnel is referred as individuals who are able judge the work they are assigned and recognize possible dangers due their specialized training, their knowledge and experience as well as their knowledge of the relevant standards. Any hazards that could be caused at the meter by the medium and the operating pressure in the instrument are be prevented by appropriate measures. Make sure that the instrument is only used where temperatures and operating pressure do not exceed the sizing data specified in the order. When mounted on vessels in which hazardous area conditions of Zone are be expected, the Media 5 Differential Pressure and Flow Meter without limit switches may be used measure flammable gases and liquids provided that the operar observes the relevant regulations on the measurement of flammable gases and liquids of Zone. This means measuring instruments suitable for connection Zone may be installed provided that: 1.) The pipes connecting the instruments have been sized and installed according the German Technical Regulations for Flammable Liquids TRbF 5 or 2.) Flame arresters or endurance burning flame arresters have been installed in the two measuring lines. Whether you have install flame arresters or endurance burning flame arresters depends on the conditions on site. It is, however, preferable install endurance burning flame arresters. You are required contact the appropriate regulary authority agree on the necessary measures. Note that it is the operar s responsibility meet the requirements specified in 1.) and 2.) and that SAMSON AG does not assume any responsibility if the operar fails do so. Proper shipping and appropriate srage are assumed. Note! The device with a CE marking fulfils the requirements of the Directives 94/9/EC (ATEX) and 89/336/EEC (EMC). The declaration of conformity can be viewed and downloaded on the Internet at EB 952 EN 3

4 Technical data Differential pressure meter Nominal range mbar Adjustable measuring span in mbar max min Nominal pressure PN 5, overloadable on one side up 4 bar Scale Scale 25, scale length approx. 162 mm, division of scale...1 % linear or squared, on request for any linear measured quantities, for measured quantities acc. equation, curve or table Performance Characteristic linear differential pressure, scale linear tank contents Deviation of characteristic < ±2.5 % (including hysteresis) Sensitivity <.5 % <.25 % Influence of static pressure <.3 % / 1 bar Limit switches 2 inductive alarm contacts A1 and A2 according EN Control circuit Values corresponding the downstream switching amplifier according EN , e.g. KFA6-SR2-Ex2.W or KFA-SR2- Ex1.W Proximity switch SJ 2-SN for hazardous areas according PTB ATEX 249 X Switching accuracy < ±2 % Reverse span, approx. <.6 % Perm. ambient temperature C, for oxygen 4 +6 C Perm. srage temperature 4 1 C Degree of protection IP 54 according DIN VDE 47-1/EN Weight, approx. Without valve block 2.6 kg, with valve block 4.6 kg Materials Version Standard version Case CuZn 4 Pb CrNi steel Measuring diaphragm and ECO/NBR seals Measuring springs, diaphragm plates, functional parts and levers Indicating unit CrNi steel Polycarbonate Note: All pressures specified as gauge pressures; all errors and deviations in % of the adjusted measuring span. 4 EB 952 EN

5 Design and principle of operation 1 Design and principle of operation The Media 5 Differential Pressure and Flow Meter serves measure and indicate the differential pressure or variables derived from the differential pressure of gases or liquids, i.e. it is used, for example, for measuring the liquid level in pressure vessels, the differential pressure between flow and return flow, the pressure drops across valves and filters as well as the flow rate according the differential pressure method. The device comprises a differential pressure cell including a measuring diaphragm and measuring springs, plus indicating unit including a pointer mechanism and a scale. The differential pressure p = p1 p2 produced by the orifice plate creates a force acting on the measuring diaphragm (1.5) proportionally the differential pressure. This force is balanced by the measuring springs (1.4) and results in a deflection of the lever (1.8). The movement of the lever in the high-pressure chamber is transmitted the pointer mechanism (2.2) located in the indicating unit by means of a flexible disc (1.9). The scale is linear for the differential pressure, and squared for the rate of flow. Version with limit switches The othed segment (2.1) carries the tags (3.1) and actuates the alarm contacts by moving the tags in the adjustable proximity switches (3.2). If the tag enters the pick-up field of the associated proximity switch, the switch becomes highly resistive (contact opened). If the tag leaves the field, the proximity switch becomes low resistive (contact closed). The switching function is activated when the tag moves either in or out of the proximity switch depending on the contact settings A1 Differential pressure cell 1.1 Measuring cell 1.2 High-pressure chamber 1.3 Low-pressure chamber 1.4 Measuring springs 1.5 Measuring diaphragm 1.6 Diaphragm plates 1.7 Diaphragm rod 1.8 Lever 1.9 Flexible disc A2 _ + Fig. 2 Functional of version with 2 alarm contacts Indicating unit 2.1 Toothed segment 2.2 Pointer mechanism 2.3 Scale Limit switches (optional) 3.1 Tags 3.2 Proximity switches for alarm contacts A1 and A2 EB 952 EN 5

6 Installation 2Installation 2.1 Arrangement of instruments for liquid level measurement The center schematic (p row) illustrated on the following page includes the additional height z in the measurement. Therefore, you should keep z as small as possible. You can select the compensation height K (see schematic on the p right of the following page) as large as required by the installation conditions on site. 2.2 Arrangement of instruments for flow rate measurement The decision whether you have secure the instrument above or below the point of measurement or whether you must install equalizing tanks or not depends on the type of process fluid and the conditions on site. The installation schematics illustrated at the botm of the following page show standard and reverse installation. Standard installation is always be preferred. Choose reverse installation only if there is no alternative which often occurs especially when measuring steam. For further details on reverse installation, we recommend that you refer VDE/VDI 3512 Part 1. Note: You need screw joints connect the differential pressure lines. In addition, the unused instrument connections must be fitted with plugs or vent plugs depending on how the instruments are arranged (see also section 3.4). Carefully clean the connections prior connecting the differential pressure lines the instrument. Do not purge the instrument with compressed air or pressurized water. At the place of installation, secure the instrument the pipe, wall or mounting plate free of vibrations. For attachment vertical or horizontal pipes, use a mounting component with a clamp. For wall mounting, use a mounting component without a clamp. For panel mounting, a mounting bracket is required (see dimensional drawing of section 7). 2.3 Media 5 indicating unit Be sure connect the high-pressure (plus) line the high-pressure connection and the low-pressure (minus) line the low-pressure connection of the instrument. 6 EB 952 EN

7 Installation Liquid level measurement Diagram including SAMSON valve block H h z K Measuring range Measured height Additional height Compensation height z h H h H h H Y K Measurement with cryogenic systems (liquid gases) Measurement at pressure vessels with condensed or noncondensed pressure cushion Measurement at open vessels with measuring instrument on the botm Flow rate measurement Measurement of liquids Measurement of steam Measurement of gases Orifice plate Equalizing tank 1) 1) 1) Separation chamber Installation: Standard Reverse Standard Standard Reverse 1) SAMSON valve blocks can be mounted upside down so that the connection assignment (+) (+) and ( ) ( ) is kept. See section 3.1 for more details. Fig. 3 Installation schematics EB 952 EN 7

8 Installation 2.4 Differential pressure lines Select differential pressure lines featuring an external diameter of 12 mm and install them according Fig. 3. Be sure select the proper arrangement. The use of screw joints ensures tight sealing of the lines. Lines which would normally be routed horizontally, must be installed with a continuous slope of min. 1:2, sloping from the orifice plate or the point that enables ventilation. The minimum bending radius must not be below 5 mm. Purge the differential pressure lines thoroughly prior connecting them the instrument. 2.5 Orifice plate assembly The process medium flows in the direction indicated by the arrow. An undisturbed, straight length of pipe is required at the inlet and outlet sides of the orifice plate assembly. With the orifice tubes supplied by SAMSON, these pipe lengths are ensured by the welded-on calibrated pipes. With orifice flanges, the straight length of pipe which must precede the orifice plate is specified in the order confirmation. The orifice plate assembly and the seals must not be eccentrically displaced with respect the pipeline. Do not install control valves such as manually operated valves or temperature regulars that continuously vary the operating state of the process medium upstream of the orifice plate assembly because the operating state is expected correspond the calculated state as much as possible. Regulars, however, which do not vary the operating state (e.g. pressure regulars) prove be advantageous upstream of the measuring instrument. d Type 9 Orifice Flange Type 91 Orifice Tube 65 Arrangement of the differential pressure lines on the orifice plate assembly Gases Steam Liquids Inlet 2 5 x d Outlet 5 x d Fig. 4 Orifice plate assembly 8 EB 952 EN

9 Accessories 3 Accessories We recommend that you install both a shuff valve and, additionally, an equalizing valve in the differential pressure lines. They are used shut off the two differential pressure lines, as well as for short-circuit switching of the indicating unit for checking zero. 3.1 Valve block A valve block (Fig. 5) with three combined valves is available as a SAMSON accessory. The valve block is directly flanged the botm side of the measuring cell. On measuring the flow rate of liquids and gases, the SAMSON valve block can also be mounted upside down allow the connections be assigned properly, i.e. (+) (+) and ( ) ( ). However, the pressure gauge connection can no longer be used due the reversed mounting and it must be sealed using an O-ring and screw cap G 1/2 - LH (see dimensional diagram in section 7). 3.2 Shut-off and equalizing valves As an alternative the SAMSON valve block, you can also install the two shut-off valves as well as the bypass valve/equalizing valve according Fig. 6. Liquid level measurement Media 5 1 Shut-off valves 2 Equalizing valve Test connection Equalizing valve Flow rate measurement From the point of measurement Bores for leading 1 Shut-off valve ( ) Pressure gauge connection Fig. 5 SAMSON valve block + Connection for measuring lines Shut-off valve (+) Fig. 6 Shut-off and equalizing valves, separate or combined as a block 2 To indicating unit EB 952 EN 9

10 Start-up 3.3 Equalizing tanks Equalizing tanks for maintaining a constant liquid column are required when measuring steam. When measuring liquids, these tanks are only needed if the indicating unit is located above the point of measurement. When measuring gas, equalizing tanks designed as separation chambers are required for draining the condensate if the indicating unit is located below the point of measurement. 3.4 Accessories for connection The instruments are supplied without screw joints (versions for oxygen are protected from contamination by means of 4 NBR blanking plugs). Required screw joints, drain or vent plugs as well as screw joints with orifice plates dampen the vibrations caused by the measured medium (especially gas) must be ordered separately. Note:! The screw joints as well as SAMSON valve blocks including order numbers are listed in the Data Sheet T 9555 EN. 4 Start-up See Fig. 6 for start-up. 4.1 Flow rate measurement For steam measurement The steam should never have direct contact with the measuring diaphragm of the instrument. For this reason, unscrew the differential pressure lines located below the shut-off valves or the valve block and fill the instrument with water. As an alternative method, wait approximately 2 minutes after start-up (steam switched on) with locked shut-off and equalizing valves or locked valve block until condensate in the differential pressure lines rises above the valve up the orifice plate. 1. Open the high-pressure (plus) line. 2. Close the equalizing valve, i.e. the bypass of the valve block. 3. Open the low-pressure (minus) line. 4. Wait a moment before you continue remove both vent plugs of the measuring cell in succession until condensate escapes free of bubbles, and retighten screws. In the same manner, vent the equalizing tanks. Lightly tap on the case of the indicating unit or the equalizing tanks promote the escape of air. 5. Check zero as described in section 5.1, and put the instrument in service again. 1 EB 952 EN

11 Operation Note: In case of reverse installation (measuring instrument located above the point of measurement), the differential pressure lines could become partially drained if the plant is relieved of pressure. When starting up again, the measuring arrangement must be vented so that it can refill with condensate. For liquid measurement 1. Open the high-pressure (plus) line by gradually turning. 2. Close the equalizing valve or the bypass of the valve block. 3. Open the low-pressure (minus) line. 4. Loosen one vent plug of the measuring cell until the air has escaped and retighten % 3 ±4 7 Scale screws 4 Fig. 7 Zero correction is achieved by turning the scale Check zero as described in section 5.1 and put the instrument in service again. 4.2 Liquid level measurement See Fig. 5 for start-up. Important! During measurement, make sure that the equalizing valve is closed and that the shuff valves are open. Note! For cryogenic applications, an open equalizing valve during measurement causes the medium circulate and, as a result, the valve block freeze up. 5 Operation 5.1 Zero adjustment If the differential pressure lines are equipped with shut-off and equalizing valves, zero can be checked even when the plant is in operation. 1. Close the shut-off valve on the plus side. 2. Open the equalizing valve. 3. Close the shut-off valve on the minus side so that a balance of pressure is obtained in the measuring cell. The pointer must indicate zero. If it does not read zero, unfasten the scale screws and turn the dial plate (adjustable by ±4 ). In case of larger deviations, remove the pointer using an appropriate ol. Align the dial plate in the middle position. Then reattach the pointer in zero position on the axis. EB 952 EN 11

12 Operation For start-up: 1. Open the minus line. 2. Close the equalizing valve. 3. Slowly but gradually open the plus line all the way. The instrument is in operation again. For applications with installed valve block, proceed as described above. 5.2 Draining When gases are measured, you must drain the condensate from the draining tanks from time time. Close the valves in the differential pressure lines (valve block) prior opening the drain plugs. 5.3 Adjusting and modifying the measuring range The measuring range of the differential pressure and flow meter is determined by the installed measuring springs. The instrument is pre-adjusted at the facry the range specified in the order. Subsequently, it can only be modified infinitely variably up approx. 6 % of the max. measuring span (for technical data, refer page 3). For best results, adjust on the test bench. Adjusting zero and checking the measuring range: 1. Adjust zero in the depressurized measuring cell as described in section Make sure that the low-pressure (minus) line is open and apply pressure the high-pressure (plus) chamber of the differential pressure cell until the pointer indicates 1 %. Read the pressure gauge and check if the adjusted pressure value corresponds the current final value of the measuring range. 3. Depressurize again. Correcting and modifiying the measuring range: 1. Loosen the screws (1) and remove the cover plate (2). 2. Loosen the mounting screw (3) so that the meter frame (4) can be moved easily. 3. Place the tip of an appropriate screwdriver in the 7 mm notch for moving the meter frame upward or downward. If you want increase your measuring range, turn the screwdriver counterclockwise the left. If you want decrease your measuring range, turn the screwdriver clockwise the right. Then tighten the mounting screw (3) again. 4. Correct zero according section Pressurize the measuring cell again until the pointer indicates full-scale value. 6. Check the final value of the measuring range, reading the pressure gauge. Should it not correspond with the desired measuring range, repeat adjustment procedure until zero and final value are properly adjusted. 7. Reattach the cover plate (2) and fasten the screws (1). 12 EB 952 EN

13 Operation 4 5% Notch for screwdriver 1 1 Screws 2 Cover plate 3 Mounting screw 4 Meter frame 5 Scale screws Note! For devices used measure oxygen, make sure the test medium is free of oil and grease. Use oil- and grease-free air or other gases, e.g. N 2. Test pressure Supply air pressure reducing station with oil filter and pressure gauge Precision regular with Class.1 pressure gauge Fig. 8 Test arrangement and modifying the measuring range EB 952 EN 13

14 Version with limit switches 6 Version with limit switches One or two proximity switches can be installed as alarm contacts (A1 and A2) as follows: Contact and function Contact made with Figure Min A1 as main contact botm edge 1.2 Min A1 as main contact Min A2 as precontact Min A1 as main contact Max A2 as main contact botm edge p edge botm edge p edge The maximum contact can also be used as a second minimum contact, i.e. as a precontact. In this case, however, there must be a minimum difference of 15 % between the switching point of the precontact and that of the main contact A Electrical connection This procedure involves connecting the alarm contacts A1 and A2 of the indicating unit an isolating switch amplifier or an alarm system according Fig A2 A1 Switching amplifier acc. EN The listed limits in the table apply concerning the connection of proximity switches certified intrinsically safe circuits in the type of protection EEx ia IIC T6 (PTB ATEX 249 X): Type 1 Type 2 U i 16 V 16 V I i 25 ma 25 ma P i 34 mw 64 mw C i 5 nf 5 nf L i 25 µh 25 µh T T6 T5 T4 T6 T5 T4 73 C 88 C 1 C 66 C 81 C 1 C 6.2 Adjusting the alarm contacts The minimum contacts A1and A2 as well as the contacts in the combination "minimum contact A1 and maximum contact A2" can be shifted in the range of 1 % of the adjusted measuring span. Minimum and maximum contacts have different designs. Contact is made when the tag moves approximately 6 mm in the proximity switch. Minimum contacts: Always adjust the switching points according the decreasing characteristic. The botm edge of the tag causes the contact be made. Maximum contacts: Always adjust the switching points according the increasing characteristic. The p edge of the contact causes the contact be made. Fig. 9 Terminal assignment of the alarm contacts 14 EB 952 EN

15 Version with limit switches Adjustment with pressure default Connect the device a switching amplifier as described in section 6.1. To the high-pressure connection of the measuring cell, apply a pressure which corresponds the desired switching point. Caution! The low-pressure connection of the measuring cell must be open for this purpose. Loosen the terminal screw of the proximity switch bracket according Fig. 1 and manually move the contact in the desired switching position (note that the middle of the bracket indicates the position). Minimum contact: From the left, move the proximity switch on the left side of the tag until contact is made. Maximum contact: From the right, move the proximity switch on the right side of the tag until contact is made. Slightly tighten the terminal screw. Check the switching point and repeat adjustment, if necessary. Adjustment range A2 Max. contact 1% Min. contact A2 % 1% % Adjustment range A1 Min. contact Fig. 1.2 Min. contact A1 Terminal screw M3 (SW 5.5) % 1% Adjustment range A1 Min. contact Max. contact A2 Fig. 1.1 Fig. 1.3 Min. contact A1 Fig. 1 Adjusting the alarm contacts EB 952 EN 15

16 Retrofitting/replacing the contact unit Adjustment without pressure default e.g. on site Connect the instrument a switching amplifier as described in section 6.1. Adjust the tag by carefully moving the pointer manually. Caution! Do not move the pointer past the currently indicated position on the dial. You may move the pointer below the indicated position. 6.3 Retrofitting/replacing the contact unit The contacts can only be retrofitted or replaced as complete units. Contact unit Order No. 1 min. contact A min. contact A1 a. A min. contact A1 and max. contact A2 When the tank is 1% full, the above action can always be performed, however, when the tank is empty and the dial indicates %, this is not possible. 1. Unscrew the case cover. 2. Remove the screws (1, Fig. 8) and the cover plate (2, Fig. 8). 3. Loosen the two scale screws (5, Fig. 8), lift the dial forward ward the pointer and then remove it upward. 4. Slide the contact unit (2, Fig. 11) on the meter from the right so that the metal tags reach in the proximity switches without uching the contacts. 5. Secure the contact unit (2, Fig. 11) the meter frame using two slotted head screws (5, Fig. 11). 6. Establish the connecting line (4.1, Fig. 11) for the alarm contact A1 below the meter frame and the connecting line (4.2, Fig. 11) for the alarm contact A2 above the meter frame. Ensure that the lines do not prevent the tags from moving in and out of the proximity switches. Moreover, make sure that the lines are not damaged when tightening the case cover later on. 7. Insert the printed circuit board (1, Fig. 11) in the positioning notch from the left and tighten it using a Philips screw (6). 16 EB 952 EN

17 Retrofitting/replacing the contact unit 8. Replace the blanking plug of the indicating unit with a cable gland (8) M12x1.5. Protect the cable gland against water entering until the signal line has been established. 9. Establish the electrical connection as described in section Reposition the dial from the p and secure it the meter frame using the scale screws (2, Fig. 8) assuring the right zero position according section Attach the case cover and screw tight preventing the connecting lines of the proximity switches from being damaged A A1 5 Positioning notch Printed circuit board 2 Contact unit 3 Meter frame 4.1 Connecting line A1 4.2 Connecting line A2 5 Slotted head screws 6 Philips screw 8 Cable gland Fig. 11 Retrofitting the alarm contacts EB 952 EN 17

18 Dimensions in mm 7 Dimensions in mm Bores for wall/panel-p mounting Center of indicating unit Two bores ø 8.5 mm for attachment rear side of the measuring cell (screws M8) (52) Two bores ø 8.5 mm for attachment valve block (screws M8) Valve block when mounted upside down Pipe mounting Ø (2) SW14, G¼ Ø13 25 Ø NG63 _ Pressure gauge connection G 1/2-LH with coupling sleeve G 1/2 for pressure gauge NG 1 and O-ring 12x2 as well as G 1/4 for pressure gauge NG 63 with seal G 1/ EB 952 EN

19 EB 952 EN 19

20 SAMSON AG MESS- UND REGELTECHNIK Weismüllerstraße 3 D-6314 Frankfurt am Main Phone: Fax: Internet: EB 952 EN S/Z 24-7