![Page 1: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/1.jpg)
Positive Displacement Blowers
Positive Displacement Definition: To lift a given volume for each cycle of
operation.
![Page 2: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/2.jpg)
History
• The machine was first invented as a more efficient water wheel. Made of wood, it was put in the millstream and as the water flowed through it, the rotors turned and power was generated for milling from the output shaft. It worked well except for a minor flaw; the wood would swell up and ruin the clearances and the mill would stop. The unit would be taken out of service and dried out, shrinking the parts to their original dimensions.
• In an effort to speed up the drying, as soon as the rotors would turn, a power source could be connected to the output shaft and the rotors spun. Someone noticed that such an arrangement would move a quantity of air and the use as an air blower was begun.
![Page 3: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/3.jpg)
Warranty
• The blower is warranted by the manufacturer (Roots, Hibon) and supported by a blower dealer for a period of 1 year. The warranty covers defect of material or workmanship. A failure of any type, the blower must be removed from the truck and shipped to the blower dealer or manufacturer
Failure to repair cycle and typical down time
Customer
Vac-Con Dealer
PD blower dealer
Blower manufacturer
Customer
1 week minimum
Determine cause of failure and submit findings to manufacturer for approval
3 weeks typical
Manufacturer approves warranty and dealer orders parts for repair.
![Page 4: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/4.jpg)
Intake rotation
Must have tight tolerances
Must maintain tight tolerances to move material
Exhaust rotation
![Page 5: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/5.jpg)
![Page 6: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/6.jpg)
P.D. Blower Construction
![Page 7: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/7.jpg)
Drive gears
![Page 8: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/8.jpg)
Driven bearings are shimmed to 9 thousandths (.009) of an inch to center the lobe in the housing
![Page 9: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/9.jpg)
Drive gearOil slinger
Shim plate
Bearing
Spring washer
Fluid seal
Vacuum seal
Drives the lobes
Lubricates gears and bearings
Centers lobes in housingSupports and allows lobes to rotate
Keeps lobes centered
Keeps oil in gear housingKeeps vacuum in housing and stops air leaking in
![Page 10: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/10.jpg)
The land is responsible for maintaining the tight tolerance between the lobe and housing. Any material ingested
will wear the land down increasing the distance between the lobe and the
housing decreasing efficiency
![Page 11: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/11.jpg)
Clearance between land and housing is 9 thousandths of an inch
About the thickness of 2 business cards
![Page 12: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/12.jpg)
Close tolerances
• Absolutely must not have any carry over.• Debris body screens absolutely must be in
place.• Final strainer must be in place• Absolutely nothing larger than 9 thousandths
of an inch (.009) can pass through the blower.
• Special care must be taken, if the blower is not going to be operated for long periods of time oil must be applied to the lobes to keep them from rusting together.
![Page 13: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/13.jpg)
Potential causes of damage
• Carryover running through the blower for long periods of time
Severe erosion
![Page 14: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/14.jpg)
Potential causes of damage
• Large debris causing the blower to stop rotation instantly
Housing cracked because of lobes stopping while running
Head plate broke in two
![Page 15: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/15.jpg)
Potential causes of damage
Over heating caused the lobe to grow (expand) too much causing lobe to head plate contact. Over heating is caused by a restriction or vacuum relief (kunkle) valves failing.
![Page 16: Vac-Con's Two-Engine PD Machine puts the Power Where You Need it!](https://reader033.vdocument.in/reader033/viewer/2022060203/559ecb3a1a28abdb338b4690/html5/thumbnails/16.jpg)
Vacuum relief valves