Becker U 4.70 Series User manual

BECKER
U 4.70-4.100
REPAIR AND SERVICE
MANUAL
04/98

U 4.70-4.100
REPAIR & SERVICE
MANUAL
PAGE 1
Introduction
This manual covers repairs and service for the following Becker models:
U 4.70SA,and U 4.100SA series oil flooded vacuum pumps.
U 4.70F,and U 4.100F series oil flooded vacuum pumps.
This manual is intended to be used in conjunction with the current parts list for the appropriate model.
Reference numbers used in this manual are position numbers as shown on the parts list. The sealing
compounds and greases referred to in this manual are the sealants and greases recommended by the pump
manufacture. These are available through your Becker Pumps Distributor.
Disassembly
1. Remove drain plug (#135) and drain oil from sump. (#61)
2. Remove bolt and washer (#190 & 188) and remove protective hood. (#181)
3. Remove 4 bolts (#194) holding motor flange (#251) to pump.
4. Remove pump coupling (#18) and key. (#24)
5. Remove inlet flange (#41) and check valve assembly.(#42+49)
6. Roll unit on to side so that oil sump is on the bottom.
7. Remove oil feed lines (# 141,#142,#158,and #150) from endshields, oil cooler and oil sump.
8. Place oil cooler in safe place and allow to drain.
9. Remove shaft end bolt (#32), cooling fan, (#30) and key. (#31) If puller is used to remove fan be
sure to protect threads in the end of the rotor by screwing a short bolt into the end of the rotor.
10. Remove oil return line.(#143)
11. Remove B-side endshield. (#16)
12. Remove pump side motor flange/A-side endshield. (#15)
13. Slide rotor (#3) out of cylinder housing. (#1)
14. Roll unit back onto rubber feet.
15. Remove bolts holding oil separator cover (#112) on and remove cover and separator elements.
(#83)
16. Remove bolts holding sump cover (#64) on and remove cover.
17. Remove coarse separator (#101) and screen. (#104)
18. Remove nuts and washers (#71 and #70) holding sump (#61) to cylinder housing. (#1)
19. Remove vanes, (#5) bearings, (#9) shims, (#8) and sealing washers (#7) from rotor.
20. Remove shaft seals (#10) from endshields. Remove gaskets, O-rings, and sealing washers from
mating surfaces of all housings.
21. Thoroughly clean all parts in suitable solvent, flush all oil lines and cooler.
22. Inspect all components for wear or damage. Thoroughly inspect rotor, endshields, and cylinder for
wear or damage. (Scoring, chatter marks, unusual wear, and damage to sealing surfaces.)
Reassembly
1. Install new shaft seals (#10) in endshields. Coat outside diameter of shaft seal with a thin coat of
Curil K2 and press seals squarely into endshields with suitable tool.
2. Apply Ambligon TA 15/2 grease between the lips of the shaft seal. Fill space approximately 1/3
full.
3. Install 1 bearing shield (#7) and 1 shim (#8) on each end of the rotor shaft and press bearing (#9)
onto shaft with appropriate tools. If bearings are shielded on one side, the shield faces the main
body of the rotor. (You can also shrink the bearings on to the shaft by heating the inner races of the
bearing to 200 degrees and quickly sliding the bearing onto the shaft.)

U 4.70-4.100
REPAIR & SERVICE
MANUAL
PAGE 2
Reassembly
4. Install new O-rings (#25 and #26) on the B-side of the cylinder housing and bolt the B-side
endshield (#16) to the cylinder housing. (#1)
5. Lightly oil vanes slots of rotor, vanes, and bearings with the recommended oil for the pump. Insert
vanes into rotor slots, (see drawing #1) vanes should be able to slide freely into slots.
6. Lightly coat the inside of the cylinder housing with oil. Then with the cylinder housing exhaust port
facing down, slide the rotor into the cylinder housing (B-side/ fan end first) take care not to damage
shaft seal.
7. Install new O-ring on A-side of cylinder housing and install A-side endshield onto cylinder
housing.
8. On F-version pumps install new discharge check valves. (#34-#37)
9. Install new gasket (#80) and reinstall cover (#67) and lower sump.(#61)
10. Install oil return line (#143) with new sealing washers.
11. Replace shaft key (#31) and cooling fan. (#30) Install and tighten shaft end bolt. (#32 and #33)
12. Reinstall oil lines (#141, #142, #158, and #150) and oil cooler. (#157) Use new sealing washers on
both sides of oil line banjo fittings.
13. Reinstall pump side motor flange/A-side endshield. (#15)
14. Install shaft key (#24) and pump side coupling. (#18) Tighten set screw to lock coupling in place.
15. Rotate assembly so that it is resting on the rubber feet.
16. Reinstall separator screen (#104) and coarse separator. (#101)
17. Reinstall sump cover (#64) with new gasket.(#77)
18. Install new oil separator elements (#83) and reinstall oil separator cover with new gasket. (#112)
19. Check motor coupling distance and install motor.
20. Reinstall inlet suction flange (#41) and check valve (#42+49)
21. Reinstall protective hood. (#181)
22. Fill unit with correct oil. (Cap. .52 gallon / 2 Liters)
23. Wire motor for correct voltage and rotation.
24. Test unit for 1 hour before installation.
Setting Motor Coupling Distance
1. Place straight edge across the machined surface of the motor connection flange on the A-side
endshield/pump motor flange (#15) and measure to the outer ring of the pump coupling. (#18)
2. Subtract 2mm (.080”) from measurement obtained in step 1.
3. Place straight edge across motor coupling (#20) and push coupling onto motor shaft far enough to
obtain the distance calculated in step 2 from the end of the coupling engagement lugs to mating
surface of the motor adapter ring. (#251)
4. Apply blue lock tight (Lock Tite #242) to motor coupling set screw and tighten.
5. Attach motor to pump.
Unit Testing
1. Check that motor is wired for correct voltage and frequency. Check unit for correct direction of
rotation.
2. Operate pump with no load for 1 to 2 minutes and check for oil leaks.
3. Place vacuum gauge and ball or gate valve on inlet port, close valve completely and note vacuum
reading on gauge. Check motor amperage. Motor amperage should not exceed maximum rated
amperage for voltage listed on motor data tag.
4. When everything is operating properly continue test for 60 minutes.

U 4.70-4.100
REPAIR & SERVICE
MANUAL
PAGE 3
Setting Rotor to Cylinder Clearance
The following procedure is required anytime a major component is replaced. (End shield, Rotor, or Cylinder)
1. Place cylinder housing on workbench so that the minimum clearance area (the area of minimum rotor to
cylinder clearance when the unit is fully assembled) is positioned on the bottom.
2. Remove locating pegs from both endshields. Mark endshields for suitable location of new holes for locating
pegs.
3. Using drill press, drill pilot holes in locations marked on endshields. Use # 16 drill bit for pilot holes. Be sure to
make pilot holes perpendicular to sealing surface of endshields.
4. Insert gauge tape (feeler gauge, shim stock, paper, or non-reinforced plastic tape) of the proper thickness (see
table #1,rotor to cylinder clearance) and approximately the same width as a rotor segment (the area between two
vane slots) into the cylinder. Gauge tape should be about 1” shorter that the rotor and should support the rotor
above the cylinder.
5. Install A-side endshield but do not fully tighten bolts.
6. Place rotor into cylinder housing making sure that a rotor segment and not a vane slot is resting on the gauge
tape.
7. Install B-side endshield but do not fully tighten bolts.
8. Using moderate pressure, press down and center endshield bolts in bolt holes, while pressing down tighten
endshield bolts. Repeat on opposite end.
9. On #9 drill bit mark drilling depth using locating peg as guide.
10. Using pilot holes drilled in step 3 drill endshields and body to proper depth. Be sure to keep drill perpendicular
to sealing surface of endshields.(Use drill press if needed.) Repeat on opposite end.
11. Clean holes with compressed air and install locating pegs.
12. Remove one endshield and rotor. Remove gauge tape.
13. Reinstall rotor and endshield.
14. Rotor to cylinder clearance is now reset, continue reassembling unit in normal manner.
TABLE #1
PUMP TYPE ROTOR LENGTH HOUSING LENGTH CYLINDER DIA VANE LENGTH ROTOR TO
CYLINDER
U 4/2.70 114.97-115.0 115.128-115.15 122.0-122.04 114.75-.80 0.07 / F 0.05
U 4/2.100 169.945-169.97 170.125-170.15 122.0-122.04 169.75-.80 0.07 / F 0.05
DRAWING # 1
U 4.000 ROTOR