Situation | Possible cause | Possible solution |
---|---|---|
Inadequate thermal performance at startup. | - Air pockets - Insufficient service fluid |
- Vent the unit - Check flow rates and temperatures |
Decreasing thermal performance with in conjunction with an increased pressure drop or a reduced flow rate. | - Fouling on heat-transfer surface | - Clean the unit and adjust flow rates to specified levels |
Decreasing thermal performance with reduced pressure drop. | -Bypass from one turn to the other caused by damaged cover gasket - Excessive operating pressure |
- Replace the cover gasket - Adjust pressure to specified level |
Excessive pressure drop with maintained thermal performance. | - Inlet or outlet is blocked | - Clean the spiral |
External leakage. | - Damaged cover gasket - Insufficient pipe support(Vibration) - Relaxation of cover gasket during shut-down - Thermal expansion during start-up |
- Replace the cover gasket - Adjust pipe support system - Tighten hook bolts - Tighten hook bolts. If leakage persists, check cover gasket |
Internal leakage. | - Heat-transfer area is damaged by erosion, corrosion or mechanical impact | - Contact KUROSE for advice. ( There is one possible for field repair. ) |
Situation | Possible cause | Possible solution |
---|---|---|
Rapid fall-off in thermal performance possibly with increasing vapour-side pressure drop. | Inadequate venting of non-condensable. | Modify gas removal system (Enlarge or fit exhaust pump or fan). |
Unstable performance fluctuating condensate or product (cooling medium) outlet temperature and condensing. |
a) Inadequate condensate removal. b) Under-dimensioned steam supply system. |
a) Modify condensate removal system (enlarge, fit removal pump or barometric leg). b) Check function of control valve and/or pressure reducing valve. Change to larger size if necessary. |
Situation | Possible cause | Possible solution |
---|---|---|
Major drop in thermal performance with increased pressure loss in the vapour side. | Inadequate extraction of non-condensables. | Modify the gas extraction system with a suitable pump. |
Unstable thermal performance with fluctuation in outlet temperature, condensate or product (cooling medium) and condensation. | a) Inadequate condensate removal system. b) The steam supply system is too small. |
a) Modify condensate removal system with a suitable pump. b) Check functioning of supply valve and/or pressure reducing valve. Replace with larger one if necessary. |
Unstable thermal performance. | a) The heating medium is unsuitable. b) Insufficient supply of a vaporising product. |
a) Adjust the flow and temperature of the heating medium (if steam, check
pressure). b) Modify the supply system (increase the size or install a pump). c) Check the liquid level, which should be approximately level to the upper side of the spiral body. |