Milton Roy mROY Instruction Manual

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®
mROY Pneumatic Capacity Control
Instruction Manual
Manual No. : 53871 Rev. : 0 Date : 05/2019
1 Rev.
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PRECAUTIONS
For Pumps with PVC & 316SS Liquid Ends WHEN USED IN SWIMMING POOLS OR SPAS/HOT TUBS (ANSI/NSF 50)
Caution on Chemical Concentration:
There is a potential for elevated chemical concentration during periods of no ow, for example, during backwash in the system. Steps, such as turning the pump off, should be taken during operation or installation to prevent this. Contact your sales representative or distributor about other external control options to help mitigate this risk.
Flow Indicating Device:
To ensure operation of the pump it is recommended that some type of ow indicating device be installed to measure water ow rates and be appropriate for the output of the pump. Contact your distributor or sales representative for further information.
Head Loss / Over Pressure Protection / Back Pressure-Anti-Siphon Valve:
• Milton Roy metering pumps are positive displacement. Head loss is not applicable to the pump.
• To ensure safe operation of the pump it is recommended that some type of safety/pressure relief valve be installed to protect the piping and other system components from failing due to excessive pressure.
• If you are pumping downhill or into low or no system pressure, a back pressure/anti-siphon device should be installed to prevent over pumping or siphoning. Contact your distributor or sales representative for further information.
Additional Operation and Installation Instructions for 316SS or PVC Liquid Ends:
• Application of this pump to swimming pool/spas only evaluated to NSF/ANSI 50.
• There is a potential for elevated chemical concentration during periods of no ow, for example, during backwash in the system. Steps, such as turning the pump off, should be taken during operation or installation to prevent this. See your sales representative or distributor about other external control options to help mitigate this risk.
• Liquid Compatibility CAUTION: Determine if the materials of construction included in the liquid handling portion of your pump are adequate for the solution (chemical) to be pumped. ALWAYS wear protective clothing, face shield, safety glasses and gloves when working on or near your metering pump. Additional precautions should be taken depending on the solution being pumped. Refer to MSDS precautions from your solution supplier. Reference a Milton Roy Material Selection Chart for aid in selecting appropriate material of construction for uids of your specic metering pump. Contact your sales representative or distributor for further information.
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TABLE OF CONTENTS
SECTION 1 - PNEUMATIC CAPACITY CONTROL................................................ 5
SECTION 2 - DISASSEMBLY AND ASSEMBLY PROCEDURE ......................................7
2.1 DISASSEMBLY ..................................................................7
2.2 ASSEMBLY .....................................................................7
2.3 CALIBRATION AFTER ASSEMBLY................................................... 7
SECTION 3 - GENERAL PERFORMANCE...................................................... 8
SECTION 4 - OPERATING SPECIFICATION .................................................... 9
SECTION 5 - TABLE OF EQUIVALENTS ...................................................... 11
LIST OF ILLUSTRATIONS
FIGURE 1. Assembly Pneumatic Capacity Control ................................................ 10
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SECTION 1 - PNEUMATIC CAPACITY CONTROL
Reference the drawing for pneumatic capacity control assembly and operating principles (pages 3 and 4) for a schematic and cross section representation of the pneumatic capacity control positioner mounted on the mRoy pump. The assembly consists of three major sections as follows:
1. The Moore Products Company, Model 73N air control valve which continuously compares the location of the piston in the pneumatic cylinder with the instrument air pressure and regulates the supply air pressure imposed on one side of the piston to obtain the required piston position.
2. The pneumatic cylinder, with a differential area piston, is the device that moves the capacity
control spool of the pump in response to the
metered supply pressure from the air control valve. The cylinder is made of a clear impact resistant plastic, so that the position of the piston is visible at all times for comparison against a “Percent Capacity” decal. (Read percent capacity at the black line of the O-ring contact).
3. The mounting ange, which is used to rigidly mount the assembly onto the standard production mRoy pump assembly, forms the end of the pneumatic cylinder and seals off the I.D. of the piston to establish a differential area between the two sides of the piston.
At time of installation, the instrument air pressure (Pi) and the supply air pressure (Ps) are connected to the corresponding ttings in the air control valve. The supply air (Ps) is routed internally to the pilot valve and it is also routed unrestricted, internally through the cylinder wall onto the small area (pump side) of the differential area piston. The instrument air pressure (Pi) is routed to a “dead end” cavity formed by the exible diaphragm assembly.
As shown by the schematic, the supply pressure
imposed on the small area side of the piston
creates a force to move the piston until it bears against, and compresses, the range spring. The range spring in turn is supported by the exible diaphragm assembly which bears against the stiff suppression spring. The diaphragm assembly is then a moveable element between two opposing spring forces. This movement of the diaphragm assembly is transmitted to the pilot valve which
acts to either increase or decrease the metered
supply air pressure (Psm) imposed on the large area side of the piston. The relationship of metered supply pressure (Psm) on one side and full supply pressure (Ps) on the other side of the differentially area piston is used to establish and maintain the required capacity control position. A xed air bleed is incorporated in the metered supply ‘pressure chamber which will maintain a small air ow across the pilot valve to provide instant response to any changes in the operating conditions.
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SECTION 1 - PNEUMATIC CAPACITY CONTROL
In operation, an increase in instrument air pressure (Pi) upsets the balanced forces and moves the diaphragm assembly to the left. This lifts the pilot valve above its seat to reduce the air pressure drop
across the pilot valve and increases the metered
supply pressure, (Psm) on the downstream side of the pilot valve, which is imposed on the large side of the air piston. The metered supply pressure will continue to increase until sufcient force is developed to move the piston to the right which increases the pump capacity.
As the piston moves, the range spring feeds back
a force proportional to the piston location so that
when the range spring pressure plus the diaphragm
force from the instrument air signal are again in
balance with the suppression spring force, the pilot valve closes and maintains a balanced pressure condition.
A decrease in instrument air pressure moves the
diaphragm assembly to the right which seats the
head of the pilot valve and lifts the pilot valve stem
off the exhaust seat. This vents the pressure (Psm) on the large side of the piston at atmosphere (Pa), then the supply pressure on the small side of the piston will move the piston to the left to decrease the pump capacity. Again the range spring feeds back to the positioner the location of the air piston until the forces are again in the balanced condition.
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SECTION 2 - DISASSEMBLY AND ASSEMBLY PROCEDURE
2.1 DISASSEMBLY
1. Disconnect the supply and instrument air pressure lines.
2. Remove the six ¼ -20 NC nuts from the air control valve hold-down studs.
3. Mark the alignment between the air control valve, gasket, cylinder and mounting ange to facilitate reassembly.
4. Remove positioner by sliding off hold-down studs.
5. Remove spring adapter plate and spring from bore of cylinder.
6. Slide plastic cylinder off mounting studs to expose piston.
7. Hold piston O.D. and remove mounting screw in center of piston.
8. Remove the mounting screw in the ange and the screw in the barrel of the ange. Now slide the ange off the pump capacity control boss.
2.3 CALIBRATION AFTER ASSEMBLY
To calibrate the pneumatic capacity control after reassembly, apply an instrument air signal corresponding to 100% capacity setting. Remove
the cover on the top of the valve positioner and use
a screwdriver to turn the zero adjust until the piston seal line corresponds to the 100% graduation on the % capacity decal. Turn the adjusting screw counter clockwise to move the piston away from the pump.
9. Use a thin screwdriver or similar tool to remove “E” ring which retains the piston adapter onto the pump capacity control spool.
This completes the disassembly.
2.2 ASSEMBLY
For assembly follow the disassembly procedure in reverse order (descending step numbers from 9 to 1) making certain that the O-rings are lubricated with pump oil or ring lubricant before assembly of the retaining part. Make certain that parts are aligned in the same way as the original assembly. Make certain the gasket between the Moore positioner and the cylinder body is positioned so that the small hole in the gasket, adjacent to the stud hole, is aligned with the corresponding hole through the plastic cylinder.
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SECTION 3 - GENERAL PERFORMANCE
The pneumatic capacity control assembly will provide accurate incremental adjustment in both
directions as a linear function of the applied
instrument air pressure. There is no tendency for the capacity control to “drift” off setting over long periods of time because
1. There is no signicant force acting on the pump capacity control adjustment spool.
2. The friction from, the sealing rings act to hold the spool in position until the pneumatic capacity control applies sufcient force to overcome this friction.
With 40 psi supply air pressure, the pneumatic capacity control cylinder will develop up to 40
pounds force in the direction to increase the
capacity setting and up to 110 pounds force in the opposite direction. Then with 100 psi air pressure applied, these forces are increased to 100 pounds and 275 pounds respectively. There is no noticeable change in control position when the supply air pressure is varied within the specied pressure range. However, the nominal force
required to overcome the seal ring friction on the
control spool is in the range of 17-30 pounds, so the pneumatic capacity control should have no difculty providing rapid, accurate adjustment of the pump capacity when the minimum specied control air pressure is applied.
It should be noted that the instrument air pressure is applied to a closed chamber in the positioner valve so that the regulator or instrument system establishing the air signal must incorporate a venting air bleed to insure accurate air signal response.
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SECTION 4 - OPERATING SPECIFICATIONS
Supply Pressure Regulated 40-100 psi.
CDA (Instrument) Pressure Range
Pump Capacity Variation over Instrument Pressure Range
Minimum Pressure Change Required to Reset Capacity
Linearity of Actuator Movement
Repeatable Accuracy of Actuator Position
Supply Air Consumption (Balanced Condition) 0.2 - 0.4 SCFM
Instrument Air Consumption 0 SCFM
Failure to Supply Pressure (Ps) Moves to 100% position.
Failure of Instrument Air (PI) Moves to 0% position.
3-15 psi standard, other pressure ranges available on special order.
0-100% rated capacity.
0.20 psi or 0.13% of full range pressure.
Within 5% of maximum capacity (maximum difference in output between calibration curve and most favorable straight line drawn through curve).
Within 1% of full stroke. (Maximum difference between two positions of output for the same value of input always approached from one direction)
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150
1000
1010
980
1070
220
1140
215
1060
1080
1120
1100
1110
1020
1040
1145
1050
- (ACTUATOR)
990
1030
1090
1130
ITEM NO. DESCRIPTION
0
220
150
150
215
980
990
1000
1010
1020
1030
1040
1050
1060
1070
1080
1090
1100
1110
1120
1140
1130
MROY PCC INSTRUCTION MANUAL
CLIP 1/4 E-RING EXTERNAL
PLUG 1 NPT LVLSL HE XS 18-8SS
PLUG 1/2 NPT LVLSL HEXS 18-8SS
ADAPTER
MOUNT FLANGE MROY A PNEU.
O-RING .921 X .139 BUNA N
INT TOOTH LOCK WASHER #6 Z PL
RD HD SCR #6-32NCX7/16 Z PLT
5/16-18 SLOTTED SHOULDER SCREW
O-RING#2-011 70 DURO URETHANE
PISTON
O-RING 2-226 BUNA N
FIL HD SCR 1/4- 20X1/2 ZPL
GASKET, PNEUMATIC CYLINDER
PNEUMATIC CYLINDER POLYCARBONA
SPRING, ACT SH -P/N 6240-23
GASKET PNEUMATIC POSITI ONER
STUD
MOORE POSTIONER MODEL 73N12F
PNEUMATIC % CAPACITY DECAL RA
1/4-20 HEX NUT SS
Figure 1. Assembly Pneumatic Capacity Control (102197100015)
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SECTION 5 - TABLE OF EQUIVALENTS
1.0333 kilograms/square centimeter
1 atmosphere Equals
1 Btu/hour Equals 0.2928 Watts
Degrees Fahrenheit Equals 1.8° Celsius + 32
1 Engler degree Equals 7.45 square millimeters/second
1 foot Equals
1 Ford cup #4 Equals 3.76 square millimeters/second
1 gallon (U.S.) Equals
1 gallon/hour (U.S.) Equals
1 horsepower Equals 745.7 Watts
1 inch Equals 2.540 centimeters
1 inch of mercury Equals
1 pint (liquid) Equals
1 pound/square inch Equals
1 Redwood Admiralty Equals 2.340 square millimeters/second
1 Redwood Standard Equals 0.237 square millimeters/second
1 Saybolt Furol Equals 2.16 square millimeters/second
1 Saybolt Second Universal Equals 0.216 square millimeters/second
101.33 kilopascals
1.0135 bars
30.48 centimeters
12 inches
0.1337 cubic feet
0.8333 Imperial gallons
3.785 liters
4 quarts
0.003785 cubic meters/hour
0.002228 cubic feet/minute
0.03442 kilograms/square centimeter
3376.5 Pascals
0.4897 pounds/square inch
0.4732 liters
16 ounces
0.06804 atmospheres
0.06897 bars
0.07029 kilograms/square centimeter
6894.8 Pascals
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Ingersoll Rand (NYSE:IR) advances the quality of life by creating comfortable, sustainable and efficient environments. Our people and our family of brands— including Club Car®, Ingersoll Rand®, Thermo King® and Trane®—work together to enhance the quality and comfort of air in homes and buildings; transport and protect food and perishables; and increase industrial productivity and efficiency. We are committed to a world of sustainable progress and enduring results.
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MROY® is a registered trademark of Milton Roy, LLC.
© 2019 Milton Roy, LLC.
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