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Pit Viper Mud Agitator Owners Manual
Introduction
Agitator Selection
Sizing Verification
Displacement Rate Calculation
Installation and Operation
Maintenance
Lubrication Recommendation
INTRODUCTION
PETRO-EQUIPMENT, INC. introduces the PIT VIPER MUD AGITATOR, a new, more compact unit that incorporates high efficiency, light weight, minimal maintenance and the high torque capabilities required for maintaining a drilling/workover fluid of uniform consistency throughout the surface mud system.
Powered by either a 1445 RPM/50 HZ or 1750 RPM/60 HZ' explosion-proof electric motor, the PIT VIPER MUD AGITATOR takes advantage of the high efficiency (94%) gear reducer to rotate the impeller at 73 RPM or 88 RPM, depending on the input power. The resulting flow pattern maintains an optimum turnover rate, keeping the mud system evenly dispersed at all times. Designed to operate efficiently under the most severe operating conditions, the PIT VIPER MUD AGITATOR is available in all horsepower and impeller types and sizes required to meet the customers needs.
The gear reducer utilizes a helical spiral bevel gear reduction system that produces a highly efficient, quiet operation. Due to the minimal power loss in the reducer, less horsepower is required at the input shaft in order to deliver the needed torque. The gear box is a cast iron, one piece, light weight, compact unit requiring a minimum of maintenance. A breather plug is provided to prevent surging of the lubricant, thereby maintaining a consistent temperature within the gear box. Both the input and output shafts are constructed of alloy steel and the gears themselves meet AGMA Class 10 quality.
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AGITATOR SELECTION
Agitators were originally employed to supplement mud guns in keeping the mud from gelling. Maintaining a consistent blend of the mud components was not considered until the mid to late 70's. Since then serious investigations of agitator design have been performed by numerous manufacturers of mud processing equipment, resulting in a better understanding of the function and complexity of mud agitators.
Several factors must be considered in the selection of an agitator in order for it to perform effectively.
- Tank dimensions, width, length, depth and, where compartmentalized, compartment dimensions.
- Ratio of impeller diameter to tank width. For optimum performance this ratio should be in the range of +/-0.3.
- Mud Weight. The maximum anticipated mud weight; if unknown use a weight of 20 ppg.
- Rig Power. The voltage and frequency (HZ) to be supplied to the agitators.
Sizing of agitators is performed by using "squares". If your tank is 8 feet wide, you should use 8 ft. X 8 ft. squares in your calculation; , if it is 12 feet wide, use 12 ft. squares. If your tank or compartment length is not an even multiple of the tank width, use the closest dimension to a square as possible. Example: an 8 ft. X 30 ft. tank would produce four 8 X 7.5 ft. squares. The tank width is always used in the determination of the impeller diameter to tank width ratio. The charts illustrated have been calculated for both 50 HZ and 60 HZ input power, producing 73 RPM and 88 RPM respectively. A D/W ratio of .03 was used in plotting the curves for fresh water, brine water, 14 ppg and 20 ppg mud.
To determine the horsepower required, select your tank width at the bottom of the chart and read up to find your impeller diameter. Locate. the curve that represents the heaviest mud weight to be used. Follow the vertical impeller Diameter line to the curve representing the mud weight and read horizontally to the left to determine your horsepower requirement. In every case, use the higher horsepower indicated by the intersection of the Mud Weight curve and the vertical Impeller Diameter.
Example 1
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Example 2
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EXAMPLE NO.1
Agitators are required for a tank 9 ft. wide X 30 ft. long X 7 ft. deep and an anticipated mud weight of 14 ppg. Rig power is 60 HZ. Work in "squares"; in this case three 9 ft. X 10 ft. squares. Locate the impeller diameter/tank width line for a 9 ft. wide tank, follow it up to the top of the graph to determine the impeller diameter of.32 inches. Follow the same line down to its intersection of the 14 ppg mud curve. Read horizontally to the left to determine the horsepower required; in this case three 5 horsepower units with 32 inch impellers would be needed.
EXAMPLE NO. 2
Agitators will be required for a pit 12 ft. wide X 48 ft. long X 8 ft. deep. Anticipated mud weight is 20 ppg and the power supply is 50 HZ. Work in "squares"; in this case four 12 ft. X 12 ft. squares. Following the 12 foot Tank Width line up to the Impeller Diameter, notice that a 44 inch impeller will be required. Come back down the Impeller Diameter line to the intersection of the 20 ppg curve to find that a total of 20 horsepower units are needed.
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SIZING VERIFICATION
To confirm the agitator selection, the Displacement Rate can be determined. This unit is the time, in seconds, required to completely displace the total volume of mud in the mud tanks. A DR of 35 to 90 is within the acceptable range. The slower the Displacement Rate (the closer to 90), the more settling that will occur in the corners and between agitators. As the Displacement Rate increases (approaches 35), vortexing and air entrapment can be expected.
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DISPLACEMENT RATE CALCUIATION
Tank volume(Gallons)
------------------------------- = # Minutes X 60 = Displacement Rate (Sec.)
Displacement(GPM)
Tank volume, as indicated above, must be calculated in gallons. To do so, multiply the length of the tank (or compartment) in feet by the width in feet and the usable depth of the tank in feet. Multiply the result by 7.459 gallons per cubic feet to obtain the desired tank volume. The Displacement Rate for Axial configuration impellers is shown in the table below.
Table 1 Displacement Rate
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Impeller
Diameter
Inches |
60 HZ
Four Axial Flow
Blades |
50 HZ
Four Axial Flow
Blades |
 |
|
28 |
3832 |
3179 |
|
32 |
5765 |
4783 |
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36 |
8179 |
7565 |
|
40 |
10886 |
9032 |
|
44 |
14974 |
12423 |
|
48 |
19387 |
16084 |
|
52 |
24592 |
20402 |
Using the facts in the previous Examples 1 and 2, calculate the GPM to verify the agitator requirements.
Example 1 -- 32" Axial impeller, 60HZ
(A) 5765 GPM (chart) X 3 (agitators) = 17295 GPM
(B) (9 x 30 x 7) x 7.459 = 14098 TANK VOLUME/GAL.
(C) DR = 14098 x 60 = 49 seconds 17295
Example 2 -- 44" Axial impeller, 50HZ
(A) 12423 GPM (chart) X 4 (agitators) = 49692 GPM
(B) (12 X 48 X 8) X 7.459 = 34371 TANK VOLUME/GAL.
(C) DR = 34371 X 60 = 41.5 seconds 49692
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INSTALLATION & OPERATION
IMPELLER POSITIONING
To ensure optimum performance, location of the impeller is critical. An Axial type impeller should be positioned with the centerline of the impeller body 0.7 X Impeller Diameter above the tank floor. A Radial type impeller should be located with the bottom of the impeller blades a maximum of 6 inches above the tank floor, or 2 inches above the bottom shaft stabilizer, if used. To determine the impeller shaft length, assume that a bottom stabilizer will be used.
AGITATOR INSTALLATION
It is essential that the agitator mounting be sufficient to support the weight and torque of the complete unit. The gear box itself must be securely bolted in position with four bolts secured with locknuts.
Remove all protective coating from the shaft and flange, using solvent if necessary. Carefully mount coupling on shaft as close to the shaft shoulder as possible. If the shaft and coupling are a tight fit, use HEAT instead of force. DO NOT HAMMER ON SHAFT. The shaft and impeller,
with bottom stabilizer in place, are then coupled to the gear box with a rigid coupling. Be certain the stabilizer is properly aligned before tightening the rigid coupling. After tightening the coupling, weld the stabilizer to the tank bottom. Check the oil level in the gear box. Install the breather plug in the plug hole at the top of the gear box and REMOVE THE PIN FROM THE CENTER OF THE PLUG.
ELECTRICAL & GENERAL
Inspect unit for damage during shipment. Verify speed, horsepower, voltage and Hertz for conformance to power supply. Eyebolts or lugs are provided for lifting the unit; additional weight is prohibited. Lifting angle must not exceed 15 degrees with shank of eyebolt. Use caution when lifting units near overhead power lines.
Agitators perform longer in a clean, well-ventilated area and should be located in a suitable enclosure to prevent access by unauthorized personnel.
Guards should be provided for exposed rotating parts to prevent injuries. Keep fingers and foreign objects away from ventilation and other openings. Applications involving high inertia loads may damage this equipment due to motor overspeed during shutdown. DO NOT force drive coupling or other equipment onto shaft, as bearing damage may result.
The power supply must agree with values on nameplate. Terminal voltage should not vary by more than +/- 10% of nameplate voltage at rated frequency. Unbalance line voltage, even a small amount, will cause overheating. Do not exceed the continuous rated operating current on the nameplate. Starting controls and overload protection should be properly sized in accordance with the National Electrical Code and the control manufacturer's recommendations.
Motor connections should be made by following instructions on connection diagram. Determine direction of rotation before connecting driven equipment. If direction of rotation label is supplied, operate only in specified direction. Rotation may be reversed on three phase motors by interchanging any two-line connections. Wiring of units, controls and grounding shall be in accordance with local and National Electrical Code requirements. Failure to properly ground unit may cause serious injury to personnel. Where unexpected starting could be hazardous to personnel, do not use automatic reset starting devices.
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MAINTENANCE
To ensure safe operation and avoid problems, it is recommended that the gear box be visually inspected every 50 hours of operating time.
It is also recommended that the following items be c,hecked each 5000 hours of operating time.
- Check oil level and add oil if necessary.
- Make sure vent hole in the breather plug is clean.
- Be sure breather plug is open before operating.
Motor for use in hazardous locations-Class I & II installations: repairs of these motors must be made by the manufacturer or manufacturers authorized service shop to maintain the U.L. listing. The U.L. listing applies to the electrical motor only and not to the belt or gear transmissions or other devices that may be connected to the motor.
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LUBRICANT RECOMMENDATION
The PIT VIPER AGITATOR gear box is shipped with a synthetic extreme pressure oil, SINTOGEAR 125, for ambient operating temperatures of -25 to 125 degrees F (-31 to 51 degrees C). Synthetic oil does not require an oil change. It is, however, recommended that oil be checked periodically for proper oil level. NEVER MIX SYNTHETIC OIL WITH MINERAL OIL.
The synthetic oils listed below are recommended by the gear box manufacturer.
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Manufacturer |
Lubricant Type - Synthetic Oil |
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COFRAN |
SINTOGEAR 125 |
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MOBIL |
SHC 629 |
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