MT Pressure Switch INSTALLATION AND OPERATING INSTRUCTIONS. Kaustubha Udyog (Orion Instruments)

Transcription

1 PRESSURE SWITCHES PRESSURE DIFFERENCE SWITCHES VACUUM SWITCHES Frm 1.5 mbar t 600 bar INSTALLATION AND OPERATING INSTRUCTIONS MT Pressure Switch Cnstructin The pressure switch is hused in a tugh Aluminium husing fitted n a stainless steel base, retained by SS screws. A calibrated scale, as als the wrking f the switch is visible thrugh the cver. The pressure capsule, at the bttm f the switch, cmprises a pressure husing (either f aluminium, r SS6), a disc, nyln reinfrced rubber / metal diaphragm and a plunger. Fr hydraulic ranges, a pistn and Oring seal assembly is used. The electrical changever is thrugh a snapactin micrswitch. 2 SPDT switching can be prvided as an ptin. Other ptins like hermetically sealed micrswitches etc, can be prvided n checking feasibility, as per the rder. The electrical wiring terminates at a terminal strip having screwed ends. The cable gland prvided is M20 X 1.5 standard and 1/2"NPT. By using apprpriate capsules and wetted parts, MT series pressure switches can be used fr thusands f applicatins. Kaustubha Udyg (Orin Instruments) S. N. 36/1/1, Sinhgad Rad, Vadgan Khurd, Pune INDIA Tel.: +91-(0) Telefax : +91-(0) / pressure@vsnl.cm / inf@rin-instruments.cm Certificate N.: FM72815 Website : BULLETIN NO. : KA170206

2 INSTALLATION DRAWING FOR HIGH RANGE PRESSURE RANGES 1 Fig. 1A INSTALLATION DRAWING FOR HIGH PROOF HIGH RANGE PRESSURE RANGES 126 (4.88) INSTALLATION DRAWING FOR FLANGED RANGE 147 (5.78) INSTALLATION DRAWING FOR HYDRAULIC PRESSURE RANGES 1 (5.82) (1.12) ANSI 1" NB 300# RF Pressure Prt Ø124 (4.88) Munting Hles, Ø7 2 Ns 1/2" NPT r (6.1) Hex A/F 22 (0.) Fig. 1B Fig. 1C (1.12) Fig. 1D Principle f Operatin The pressure in the pressure capsule is cnverted int frce by means f a reinfrced rubber / metal diaphragm and a calibrated pistn, which is balanced by a cmpressin spring frm abve. When the frce generated by the pressure in the pressure capsule exceeds/falls beynd the balancing spring frce, an electrical element is actuated thrugh a bell crank lever mechanism fr accurate switching. Munting Please use the pressure switch well within the pressure / vacuum / pressure difference as als the electrical parameters The high pressure range pressure switches can be munted in any directin. 1) Please refer figure fr the apprpriate switch being used. a) Pressure / Vacuum switches can be munted directly in case the munting is rigid. b) Fr panel munting, fix the bracket prvided t the pressure / vacuum switch. Please use M5 blts f apprpriate length thrugh the munting hles. If the equipment is subject t vibratin, please use rubber washers / pads between the panel and the switch. 2. Cnnect the pressure tubing t the pressure / vacuum prt (s). The pressure prt size is generally 1/4" B.S.P. female, unless specially rdered therwise. Other sizes can be btained via adaptrs. Electrical Cnnectins Pressure switches will generally have nly ne SPDT micrswitch. Pressure switches with tw SPDT micrswitches can als be prvided. Fr 2 SPDT micrswitches, the scale will crrespnd t ne micrswitch. The setpint f the ther micrswitch will vary and the n-ff differential f the ther micrswitch will depend n the stage difference between the tw setpints. Please use electrical lads well within the limits specified fr the micrswitch. Wiring Please refer figure 2. a) Remve the tp cver. b) P a s s t h e c a b l e thrugh the cable gland (usually prvided with switch) and cnnect the wiring as per the wiring diagram. The wiring cde is as per the details given belw. terminal 1 : (C) Cn terminal 2 : (NC) Nrmally Clsed terminal 3 : (NO) Nrmally Open Fig. 2 Z 2 3 Please discnnect supply befre wiring the switch, r remving the wiring. The cver shuld nt be remved, if the supply is n. 1 2

3 Set Pint Adjustment Ensure the supply is ff, befre setting the switch. Status f cntacts can be checked with a multimeter / cntinuity tester. A ) Fr switches with fixed differentials : Refer figure 3 1) Remve the cver. The retaining screws are engaged in the cver, just lsening them shuld unfasten the cver. 2) Adjust the desired setpint n the scale. 3) Apply the desired cutin (lwer) / cutut (higher) pressure t the pressure switch. 4) Sme minr adjustment will be required t achieve the exact cutin (lwer) / cutut (higher) pint, which can be checked with the help f a prper pressure / vacuum measurement device. 5) Replace the cver and tighten the screws. B) Fr adjustable differential mdels Please refer Figure 3 1) Decide the cut-in (lwer) pressure P1 & the cut-ut (upper) pressure P2. The differential will be (P2 - P1). 2) Remve the cver. The retaining screws are engaged in the cver, just lsening them shuld unfasten the cver 3) Set the cut-in pint n the main-scale with the help f the set-screw. 4) Turn the differential screw t the extreme psitive end. 5) Apply the desired cutut (higher) pressure t the pressure switch 6) Decrease the differential pressure setting by turning the differential screw till cntacts changever. 7) Sme minr adjustment will be required t achieve the exact cutin (lwer) / cutut (higher) pint, which can be checked with the help f a prper pressure measurement device. 8) Replace the cver and tighten the screws. Fig. 3 Enclsure Operating Temperatures: The perating cnditin temperature restrictins fr the Flameprf switch FC are as fllws: Ambient : -5 C t +60 C Operatinal (all mdels): -5 C t +80 C (150 C fr metallic diaphragms) Nte : Switches with temperature ranges beynd the nes specified abve can be supplied n request. strage :-5 C t +60 C Truble Shting Tips Generally n prblems are bserved if the pressure switch selectin, wiring and the setpint is prper. Fr a pressure switch selectin prcedure, please cnsult ur sales ffice. Fr prperly selected pressure switches, if fllwing symptms are bserved, the likely causes and remedies are as stated belw. Symptm 1: Switch des nt perate 1) Wiring may nt be crrect. Check electrical cnnectins t the pressure switch, if they are as per the wiring diagram. 2) Pressure des nt reach the pressure prt. a) Check if the entry t the pressure capsule is nt blcked by frzen prcess r scales r impurities in the prcess. i) If this is the case, try freeing the blcked path by a blunt tl in case f scales r impurities. ii) Fr frzen prcess, it is advisable t use chemical seals. DO NOT OPEN THE PRESSURE CAPSULE IN ANY EVENT. If the cause is nne f the abve mentined prbabilities, prceed as per the fllwing steps. b) Check the system pressure & set pint f pressure switch. Fr use f pressure switch fr falling setpints, system pressure has t be greater than cutin pint. Fr use f pressure switch fr rising setpints, the system pressure may nt be reaching / exceeding the cutut pint. i) Fr adjustable differential mdels turn the differential screw t the extreme negative end. ii) Use 'T' cnnectin & cnnect calibrated pressure gauge t the 'T' cnnectin as shwn in the figure 4. iii) Adjust the setpint such that the system pressure is greater than the cut-ut pint f the pressure switch. iv) If the switch still des nt perate, remve the pressure switch physically frm the system. There shuld be cntinuity between terminals 1 & 2. If n cntinuity is bserved, the pressure switch shuld be returned t the factry. Fig. 4 Differential Screw Set Screw 'T' cnnectin Calibrated Pressure Gauge System Pressure 3

4 Symptm 2: Shrt Wiring Islate the switch electrically. Check the cntinuity between terminals and the screws fitted t the bdy. If n cntinuity is bserved in between any f the terminals and screws fitted t the bdy, check the shrt cnnectin elsewhere in the circuit. If cntinuity is bserved, the wires f the pressure switch have internally tuched the bdy, and the switch shuld be returned t the factry. Symptm 3: Leakage In case leakage is bserved, the pressure switch has t be returned t the factry withut pening the pressure capsule. Check fr the fllwing likely causes and use a new switch taking prper precautins. a) System pressure is greater than wrking pressure : Use an verrange prtectr r a switch with apprpriate maximum wrking pressure. b) Incmpatible wetted parts : The wrking medium may nt be cmpatible with wetted parts, which damages the sealing f the prcess frm wrking parts. Use a chemical seal fr the pressure switch r use prper cmpatible wetted parts. c) Excessive prcess temperature : Prcess temperature may exceed maximum allwable temperature, which in turn damages the diaphragms. Use an impulse tubing f prper length fr cling the prcess temperature. There may be a pressure drp depending n length f the impulse tube used. Adjust the setpint f the pressure switch accrdingly. Symptm 4: Chattering 1) Check the system pressure fr surges. Chattering is bserved where the system pressure is clse t the cutin / cutut pint and the surge pressure exceeds the n-ff differential. Use a pressure switch with an adjustable differential r use surge dampers in yur system. 2) If there is a relay in the circuit, check if the relay is prperly plugged in. Chattering may be due t lse cntacts. INSTALLATION DRAWING FOR HYDRAULIC DIAPHRAGM PRESSURE RANGES 136 (5.35) INSTALLATION DRAWING FOR HIGH RANGE ΔP RANGES INSTALLATION DRAWING FOR HIGH RANGE DP RANGES 165 (6.49) 144 (5.66) A/F 19 (0.74) MOUNTING HOLES, Ø7 Munting Hles Ø7 2 Ns 2 Ns. Munting Hles Ø7 Pressure Prt M20x15 Lw Pressure Prt High Pressure Prt High Pressure Prt (0.7) Fig. 1E 50.8 Sq Lw Pressure Prt Fig. 2A Fig. 2B INSTALLATION DRAWING FOR HIGH RANGE BELLOWS RANGES Fig. 2C 1 4

5 INSTALLATION DRAWING FOR LARGE BORE HIGH RANGE PRESSURE RANGES Fig. 1E 145 (5.70) 25 (0.) 1" BSP INSTALLATION DRAWING FOR HIGH RANGE COMPOUND RANGES Munting Hles Ø7 2 Ns. Fig. 2B INSTALLATION DRAWING FOR LOW RANGE COMPOUND RANGES Fig. 2A Hex (0.74 Hex) 158 (6.27) Pressure prt 1/4" BSP(F) Ø 65 (2.55) 1/4" BSP(M) Munting Nut INSTALLATION DRAWING FOR LOW RANGES 158 (6.27) Fig. 2C 1 Pressure prt 1/4" BSP(F) Ø 65 (2.55) 1/4" BSP(M) Munting Nut 5

6 INSTALLATION DRAWING FOR LOW RANGE PD RANGES (6.11) Fig. 1E 152 (1.72) (0.47) 71.0 (0.47) Munting Nut Lw Pressure Prt 1/4" BSP (M) 19 (0.74) 38 (1.49) High Pressure Prt INSTALLATION DRAWING FOR TEMPERATURE RANGES Fig. 2A ns Bulb dia S.S. Capillary 2.0 Mtr. Lng (Optins avail.) Munting Nut 3/8" BSP (Optins avail.) 6