PD Flow Meter Service Training Liquid Controls PD Flow Meter Service Training Installation, setup, operation and troubleshooting Liquid Controls LLC © 2004 A Unit of IDEX Corporation

Positive Displacement Meter

The meter housing (1) is designed with three cylindrical bores (2) The meter housing (1) is designed with three cylindrical bores (2). Three rotors, the blocking rotor (3) and two displacement rotors (4,5), turn in synchronized relationship within the bores. The three rotors are supported by bearing plates (6,7). The ends of the rotors protrude through the plates. The blocking rotor gear (8) is placed on the end of the blocking rotor. The displacement rotor gears (9,10) are placed on the ends of the displacement rotors. These gears create the timed Relationship between the three rotors.

As fluid moves through the meter housing, the rotor assembly turns As fluid moves through the meter housing, the rotor assembly turns. Fluid is broken into uniform sections by the turning rotors. Fluid displacement happens simultaneously. As fluid enters, another portion of the fluid is partitioned and measured. At the same time, the fluid ahead is being displaced out of the meter. Since the volume of the bores is a known value, the same amount of fluid passes through the meter during each revolution of the blocking rotor. The exact amount of fluid that has passed through the meter can be accurately be determined.

Hydraulically balanced design Product flowing through the meter exerts a dynamic force that is at right angles to the faces of the displacement rotors. The meter is designed so that the rotor shafts are always in a horizontal plane. This results in no Axial thrust, therefore there is no need for thrust washers or bearing. The rotors automatically seek the center of the stream between the two bearing plates, eliminating wear between the ends of the rotors and the bearing plates No wear results in no metal fatigue and no friction.

Mounting Arrangements

Installation Make sure any necessary safety precautions have been taken. Install the meter and components in conformance with state and federal construction, electrical and safety codes. Prior to installing the meter, ensure that the entire meter is flushed of all debris with a liquid that is compatible with the material of construction within the meter. Keep external surfaces of the meter clean. The meter must always be securely bolted to a platform or support. NEVER HANG A METER ON THE CONNECTING PIPING! Prevent pipe strain or stress when making meter connections. THE WEIGHT OF THE PIPES MUST ALWAYS BE SUPPORTED INDEPENDENT OF THE METER! Install the meter on the downstream (discharge) side of the system pump. PRODUCT SHOULD NEVER BE PULLED (SUCTIONED) THROUGH THE METER.

Installation (cont) ALWAYS position the meter with service in mind. Install a strainer on the inlet side of the meter to avoid foreign debris such as weld slag from entering the measuring system. Ensure that the metallurgy of the meter is correct for the given type of liquid. A meter should not be used with a different liquid from the original liquid specified unless the physical characteristics and pH rating are similar and the application has been verified by Liquid Controls or through a full service distributor. Read the manual as well as the supporting literature provided in the meter packet, shipped with each meter. If you have any questions, consult Liquid Controls or a Liquid Controls full service distributor.

Operation Requirements Meter must remain full of product at all times. Upstream lines must be maintained full to prevent air from entering the meter Every meter should be calibrated in the field, under actual service and installation conditions. Provide a means of conveniently diverting liquid for calibration purposes. Give careful attention to system plumbing and piping, keeping the system free of entrained air or vapor. Follow the installation guide lines provided by the pump manufacture to minimize air and vapor elimination issues. On vehicle tank installations, piping layout and tank design are important in preventing problems with split compartment test conformance. Avoid Hydraulic shock and Thermal Expansion. Both are extremely harmful to the critical measuring components within the measuring chamber. Pressure relief valves should be used in any portion or branch of the system that might be closed off by closure of operating valves or block valves. For liquids that tend to flash or vaporize easily at higher ambient temperatures, it is desirable to use flooded suctions and piping sized larger than the normal pump size.

Startup and Operation Prior to meter start up: Ensure that the meter is properly secured. Ensure that all connections are tight. Ensure that all valves are in the closed position. When placing the meter into service: The meter and system must be filled SLOWLY with liquid and be free of air prior to start up. Extreme care should be taken at this time to avoid damaging the meter. System may be filled by gravity (recommended) or by the use of a pump when filling the system with liquid for the first time.

Gravity Filling* Verify all valves up and down stream of the meter are closed. Crack open the valve located at the storage tank. The meter register will start to move then stop provided there is not another valve between the tank and the meter inlet. If there is another valve between the tank and meter, repeat this step for each valve until the meter is exposed to the liquid. Once you verify the meter has registered liquid volume and stopped, slowly proceed to fully open the tank valve. With the valve(s) between the tank and the meter inlet fully open, proceed to the valve located down stream of the meter. SLOWLY open the down stream valve until the meter register starts to move. Once the product is flowing from the end of the system, the down stream valve can be fully opened. NOTE–Do not allow the meter to run faster then 25% of the max flow rate during startup. Never exceed the max flow rate marked on the meter. *Systems with positive head pressure from storage above the inlet port of meter

Maintenance Prevent pipe strain or Stress – The meter and accessories should be able to be easily removed without affecting the pipes or the pipe alignment. Never leave any of the pipes hanging. Seasonal meter storage – If meter is used for seasonal work, at the end of each season, the meter, including front and rear covers should be removed from the system and thoroughly flushed with a compatible liquid. If water is used to flush the meter, ensure that the meter is completely drained and the all internal components are dried. Immediately refill the meter with a compatible liquid to prevent corrosion. Machined surfaces – Do not mar or scratch any of the precision machined surfaces by prying or sanding parts. Reassembling the meter – Ensure that all machined surfaces are free of burrs and mars. Repair pulled threads – Use threaded insert fasteners (heilacoils) to repair damaged or stripped threads.

Important! Inspect and clean all critical surfaces like gear teeth, rotors, and internal housing faces. Remove any crystalline formulations using a fine emery cloth or a fine wire brush. Be careful not to mar or alter the shape of any of the parts. Changing the shape of the parts may interfere with their operation. Remove nicks and burrs on metal parts with a stone. Remove all grit and other foreign particles. These may also damage parts and interfere with proper operation. Replace all parts that appear worn or damaged.

Torque all fasteners such as screws and bolts in accordance with specifications listed on the torque chart in the M/MA manual. Examine all fasteners to make sure they are not bent rusted or pulled. If bolt (s) are found bent, examine the housing and check the covers for flatness. Use a straight edge to determine flatness. Use anti-seize – When removing or replacing bolts, always coat the bolts with anti-seize.

Flange gaskets – When removing flanges that use flange gaskets, carefully remove all residual gasket material making sure the flange surface is clean. Always discard the old flange gaskets and replace with new. Look for gaps – Use a feeler gauge to check for gaps between the bearing plates and the housing. If gaps are found, check the bearing plates for flatness using a straight edge. Check ‘O’-rings – Cracked, rough or worn ‘O’-rings should always be replaced. If an ‘O’- ring looks nibbled, this may be a sign of shock problems in the systems. Bearing plates – Check bearing plates for flatness. Warped bearing plates are also a sign of problems resulting from shock. Seals – Check with local regulatory agency to determine if removing seals will require the system to be recalibrated.

Reversing The Meter Registration Flow direction of the meter is specified by the customer when the meter is ordered. The standard flow direction is Left to Right when facing the front of the meter. A red pressure sensitive label indicating the inlet is affixed to the meter at the time of shipment. Reversing the drive to the register is accomplished by reversing the position of the adjuster drive gear (face gear) relative to the pinion gear of the packing gland.

Troubleshooting the Meter PROBLEM: Leakage past the packing gland shaft housing from internal metering chamber: Leakage from the cover gasket: PROBABLE CAUSE AND SOLUTION: Internal seal of packing gland assembly is worn. Gasket has been damaged due to shock pressure or the cover bolts have not been tightened sufficiently. Tighten the cover bolts to the proper torque. If problem persists, remove the cover and check the cover for flatness. NOTE: Two common causes of packing gland leakage are thermal expansion and hydraulic shock. The use of a pressure relief valve is recommended to avoid this hazard. Hydraulic shock occurs when a large volume of liquid is moving through the pipe line at some flow rate and a valve is suddenly closed. The mass of the liquid flowing through the pipe line acts as a battering ram causing a shock effect within the meter. To avoid this hazard, a slow closing two stage valve should be used with the meter.

Troubleshooting the Meter PROBLEM: Product flows through meter but register does not operate: PROBABLE CAUSE AND SOLUTION: Check packing gland and gear train. Ensure that the Packing gland is turning with the meter. Ensure that the Packing gland gear is driving the face gear and that the drive shaft is turning properly. On M60 and M80 models, check to ensure the blade drive is not sheared. This may be caused by starting flow too rapidly. With the register removed, and the meter drive components turning, look to ensure that the output of the adjuster is turning. If it is not, replace the adjuster. If all meter parts are turning properly, the register should be removed and checked. The register should be repaired by a trained mechanic.

Troubleshooting the Meter PROBLEM: Breaking teeth on the timing gears: Product flows through the meter but the register does not record correctly: PROBABLE CAUSE AND SOLUTION: Product flow through the meter is starting and/or stopping too rapidly. Install a 2 stage valve if applicable to give the meter a softer closure. Pump bypass is not adjusted properly Meter (Adjuster) is not properly calibrated. Recalibrate the meter. The register was installed with an incorrect gear plate or gear ratio. Remove the gear plate from the register and verify that the correct gears are installed and placed in the correct pattern. Air in the system. Evaluate the system to see if air can be removed. Install an Air Eliminator when able.

Troubleshooting the Meter PROBLEM: Breaking teeth on the timing gears: Product flows through the meter but the register does not record correctly: PROBABLE CAUSE AND SOLUTION: Product flow through the meter is starting and/or stopping too rapidly. Install a 2 stage valve if applicable to give the meter a softer closure. Pump bypass is not adjusted properly Meter (Adjuster) is not properly calibrated. Recalibrate the meter. The register was installed with an incorrect gear plate or gear ratio. Remove the gear plate from the register and verify that the correct gears are installed and placed in the correct pattern. Air in the system. Evaluate the system to see if air can be removed. Install an Air Eliminator when able.

Troubleshooting the Meter PROBLEM: The meter runs too slowly: PROBABLE CAUSE AND SOLUTION: The internal mechanism of a valve is faulty. Valve does not fully open. Repair or replace the valve. The meter gears or rotors are partially corroded enough to slow up the rotation of the parts. Thoroughly clean the meter. There is a downstream restriction. Remove restriction if able. The Strainer basket is clogged. Thoroughly clean or replace the strainer basket.

Ordering Replacement Parts Refer to the exploded view drawings on pages 27-31 of the M/MA Manual. Find the four digit item number for the part you want to order.

Ordering Replacement Parts Locate the computer printout title Parts List that was inserted in the packet along with the owners manual and look up the item number to find the corresponding part number for the item. The part number represents an individual piece, a kit, or a complete assembly. Complete Bill of Materials (BOM) for most meters are also available on the Liquid Controls public website. Always check the website for the most current BOM.