NOHKEN INC Rotating Paddle Level Sensor Model R7 Rotating Paddle Level Sensor Ideal for powders, solids, and granular material Product Overview R7 is a solid level measurement sensor that is ideal to incorporate in plastic processing machinery or cereal processing machinery. The sensor has a paddle that is projected to the tank and rotates slowly. Without material around the paddle, it keeps rotating. When material reaches the paddle, the rotation stops and the output signal is given. Principle of Operation 1) Without material around the paddle Spindle and paddle, connected to the motor via the slip mechanism, slowly rotates as the motor rotates. 2) With material around the paddle Paddle rotation is impeded by the material, and the motor revolves with the spindle as its axis. The motor revolution causes the pin on the motor to actuate the microswitches; turning on the signal output and turning off the motor rotation, to give an output signal and stop the motor revolution simultaneously. 3) Reset When the material descends and the paddle is no longer covered by it, the pin on the motor returns to its original position by the spring force, causing the microswitches to reset and thus the motor and the paddle to resume rotation. 4) Slip mechanism When downward flow or other excessive force causes the spindle to rotate, the slip mechanism on the connection of the motor shaft and the spindle makes the spindle slip. This prevents constrained rotation of the motor, and protects the motor from damage. - 1 -
Features Compact and Low Cost R7 utilizes a miniature motor and plastic devices for main components, making itself a compact, lightweight, and low cost sensor. Easy Torque Adjustment Remove the cover, and change the spring position. That s all you have to do to achieve the best torque. Slip Mechanism The durable magnetic slip mechanism of R7 prevents excessive force applied on the paddle from damaging the motor. Easy Maintenance Maintenance is easy as the internal components can be removed while the sensor is mounted on a tank. Specifications Model Object Principle R7-Z (Standard) R7-ZL (Long Type) Plastic pellet, Powder, Grain etc. Rotating Paddle ( CE Marked ) Drawing Material Temp. Process side Housing/Body Process side Ambient Power supply Revolution Switch rating Detection torque Protection class Mounting Cable entry Color L length Mass PC, 304SS, Brass(C3604BD), Aluminum Die Casting(ADC12), NBR, PTFE ABS, Aluminum Die casting (ADC 12) -10 to 70 (no-freeze) -10 to 45 (no-dew condensation) 24/100/110/115/120/200/220/230/240 V AC, 50/60 Hz (Specified with order) 1 rpm at 50 Hz(power freq.) / 1.2 rpm at 60 Hz(power freq.) Microswitch, 250 V 3A AC, 30V 4A DC (Restive Load) Approx. 50 mn m IP65 or equivalent G 3/4" 1 G 1/2" or equivalent 2 Munsell 10B 5/6 93 mm 1,000 mm Max. 3 Approx. 0.7 kg Approx. 1.8 kg 4-2 -
Model Object Principle R7-X (Standard) R7-XL (Long Type) R7-XT (High Temp.) Plastic pellet, Powder, Grain etc. Rotating Paddle Drawing Temp. Material Process side Housing/Body Process side Ambient Power supply Revolution Switch rating Detection torque Protection class Mounting Cable Color L length Mass PC, 304SS, Brass(C3604BD), NBR, PTFE 304SS, Brass(C3604BD), NBR, PC, Aluminum PTFEDie casting PC, Aluminum Die casting (ADC 12) (ADC 12), Aluminum Alloy(A2017BD) -10 to 70 (no-freeze) -10 to 120 (no-freeze) -10 to 45 (no-dew condensation) 24/100/110/115/120/200/220/230/240 V AC, 50/60 Hz (Specified with order) 1 rpm at 50 Hz(power freq.) / 1.2 rpm at 60 Hz(power freq.) Microswitch, 250 V 3A AC, 30V 4A DC (Restive Load) Approx. 50 mn m IP40 or equivalent G 3/4" 1 VCTF 5 0.5 mm 2 ( φ10.5 300 mm) Munsell 10B 4.5/5 89 mm 1,000 mm Max. 3 100 mm Approx. 0.5 kg Approx. 1.6 kg 4 Approx. 1.5 kg Notes: Stainless paddle (304SS, 2-vane) is optionally available. 1 Special mounting flange for R7 is optionally available. 2 Cable gland, JIS F 20a (G3/4), is optionally available. 3 Point load for L=1,000 model: 134 N Max for EX, 94 N Max. for ZL 4 When L=1,000 Part Name Paddle and body shapes vary with - 3 -
Mounting Options Sandwich mounting Thread mounting 1) Remove the split pin fixing the paddle. 2) Disassemble the paddle, mounting nut, washer and gasket. 3) Mount the sensor on the hopper. 4) Fit the gasket, washer and mounting nut in this order on the threaded connection. Tighten the mounting nut with a wrench. 5) Mount the paddle on the spindle. Insert the split pin, and bend the tines apart with a plier to secure the paddle. 1) Remove the split pin fixing the paddle. 2) Disassemble the paddle, mounting nut, washer and gasket. 3) Apply sealing compound on the threaded connection. 4) Fit the mounting nut on the threaded connection. Mount the sensor on the hopper, and secure it with the mounting nut. 5) Mount the paddle on the spindle. Insert the split pin, and bend the tines apart with a plier to secure the paddle. Simple flange mounting(optional) 1) Remove the split pin fixing the paddle. 2) Disassemble the paddle, mounting nut, washer and gasket. 3) Fit the flange, gasket, washer and mounting nut in this order on the threaded connection. Tighten the mounting nut with a wrench. 4) Mount the paddle on the spindle. Insert the split pin, and bend the tines apart with a plier to secure the paddle. 5) Mount the flange on the hopper with bolts and nuts. Special flange for R7-X is optionally available. Threaded flange mounting (optional) 1) Remove the split pin fixing the paddle. 2) Disassemble the paddle, mounting nut, washer and gasket. 3) Apply sealing compound on the threaded connection. 4) Fit the mounting nut on the threaded connection. 5) Mount the sensor on the flange and secure it with the mounting nut. 6) Mount the paddle on the spindle. Insert the split pin, and bend the tines apart with a plier to secure the paddle. 7) Mount the flange on the hopper with bolts and nuts. - 4 -
Torque Adjustment R7-X. R7-XL, R7-XT Follow the instruction below that suits your application to achieve best torque. Spring and holes used for adjustment are located on the switch plate. See below. 1) Standard Spring is fitted to the hole B. Torque will be approximately. 55 mn m in this state 2) Small solid load If small solid load causes error, use the hole C or D. The torque will be approximately 46mNm for the hole C and 38mNm for the hole D. 3) Excessive vibration If hopper vibration causes error, use the hole A. The torque will be approximately 62mN m. R7-Z, R7-ZL Follow the instruction below that suits your application to achieve best torque. Spring and notches used for adjustment are located on the switch cover. See below. 1) Standard Spring is fitted to the notch B. Torque will be approximately 38 mn m in this state. 2) Small solid load If small solid load causes error, use the notch C or D. The torque will be approximately 30.9 mn m for the notch C and 26 mn m for the notch D. 3) Excessive vibration If hopper vibration causes error, use the notch A. The torque will be approximately 50mN m. Wiring Example Alarm circuit - 5 -
Control circuit for filling Control circuit for discharge Note Ensure ample space around the mounting location for mounting and maintenance. Consider the angle of repose and mount the sensor so that the material will reach the paddle. Be extra careful when the sensor is used for high alarm. - 6 -
Ensure deposit will not affect operation. Ensure bridge formation will not affect operation or damage the sensor when it breaks. If the material level exceeds the sensor location by 1 meter or more, provide a guard to protect the sensor. Ensure falling material will not damage the sensor. If such a location is inevitable, provide a guard to protect the sensor. Troubleshooting Sensor does not trip alarm with material at the alarm point. << Causes >> << Corrective Action >> The paddle is not covered by the material due to the angle of repose. Relocate the sensor. Solids density is too low. Adjust torque (change spring position). Coefficient of friction of the material is so low that solid resistance applied on the paddle is too small. Adjust torque (change spring position). Microswitch is faulty. Replace with a new one. - 7 -
Paddle does not resume rotation even after the material descends below the detection point. << Causes >> << Corrective Action >> Paddle is in the material (deposit). Relocate the sensor. Spring is too weak to return to the original position. Adjust torque (change spring position). Microswitch is faulty. Replace with a new one. Paddle does not start rotation at startup. << Causes >> << Corrective Action >> Wiring is incorrect. Ensure no incorrect connection. Motor is faulty. Replace with a new one. Microswitch is faulty. Replace with a new one. NOHKEN INC. Overseas Dept. Export sales section 15-32, Hiroshiba-cyo, Suita-city, Osaka, 564-0052, Japan Tel:06-6386-8149 / Fax:06-6386-8307 E-mail:overseas.dept@nohken.co.jp URL:http://www.nohken.com February, 14, 2014 Rev.0-8 -