Varisco S.p.A.
Z.I. Nord - Terza Strada, 9 - 35129 PADOVA – ITALY
Tel.+39.049.8294111 Email: [email protected]
Fax+39.049.8076762 Web: www.variscospa.com
17
9
X
X
X
Air leakage at intake
10
X
X
X
X
Difficult intake
11
X
X
X
X
Air intake from seal or packing
12
X
X
X
X
Too Low speed
13
X
X
X
X
Wrong direction of rotation
14
X
X
X
Available NPSH below required
15
X
X
X
X
X
X
The pump is working dry
16
X
X
X
The stator is faulty – burned-over
17
X
X
X
X
X
Spoilt stator. Check rubber
18
X
X
X
X
X
Faulty rotor
19
X
X
X
X
Faulty connecting rod
20
X
X
The pump is not aligned to the elastic joint
21
X
X
Broken connecting rod
22
X
X
Spoilt bearings
23
X
X
X
Too high speed
24
X
X
X
X
X
Excessive viscosity
25
X
X
X
X
X
X
X
The gland needs to be adjusted
26
X
X
X
Inadequate sealing system
Reference for malfunctioning removal:
1) Fill the pump with suitable product, gliceryn or soap (DO NOT USE any kind of oil if an EPDM rubber stator is
used).
2) Check on the order for details concerning electric connections and compare.
3) Measure pressure with a manometer and compare that with the order.
4) Remove unknown material and replace damaged parts.
5) If the temperature can not be lowered, install a downsized rotor.
6) Check if the fluid corresponds to the order, change stator rubber.
7) Increase the liquid percentage. Install a grid at intake.
8) Clean the pump and repeat the operation after each single use.
9) Increase the level of liquid at intake to prevent air intake.
10) Check seals and carefully tighten the pipes unions.
11) Tighten or replace the gland. If a mechanical seal is used, carefully clean and replace it if necessary.
12) Increase rpm.
13) Modify electric connections.
14) Increase the pressure at the inlet lowering the pump position and lower the inlet fluid temperature.
15) Fill the pump, install a device preventing dry working.
16) Replace the stator.
17) Replace the stator, check if the fluid corresponds to the order and if necessary change stator rubber.
18) Replace the rotor and try to identify the cause, which may be abrasion, corrosion or cavitation.
19) Replace worn parts.
20) Re-align pump and elastic joint.
21) Replace broken part and re-align.
22) Replace bearings, lubricate and tight.
23) Lower rpm through variator.
24) Check viscosity and compare it with the order.
25) Check specific weight and compare it with the order.
26) Choose a different mechanical seal or packing.
Note: For any query, please contact Nova Rotors or our local agent.
9 DISASSEMBLY AND ASSEMBLY OF COMPONENTS
PREMISE
1. Comply with the safety measures set out in Chapter 2 of this Manual.
2. The pump and its piping shall be emptied and cooled.
9.1 DISASSEMBLY OF ROTOR-STATOR
1. Disconnect the pump from intake and delivery pipes.
2. Support the pump body (01) with wooden blocks (02) under the stator (03).
