Reasons Why rotary airlock valve Runs Normally But Does Not Discharge Materials

Reasons Why rotary airlock valve Runs Normally But Does Not Discharge Materials

The star unloader(rotary airlock valve)operates stably with rotating rotor,but fails to output materials continuously.This fault often occurs in dust removal,metallurgy,chemical and bulk material conveying systems.It will lead to material accumulation in the upper hopper,blockage of feeding pipeline and abnormal production.The main causes and corresponding solutions are summarized as follows.

Main Causes

Material arching and bridging inside the hopper

Powder and fine particle materials are easy to form material arching,bridging and vacuum adhesion above the unloader inlet.Although the rotor rotates normally,no material falls into the unloader cavity,resulting in no discharging phenomenon.

Material moisture and viscous adhesion

High moisture content of conveyed materials causes powder to stick to the inner wall of hopper and rotor blades.Materials adhere and accumulate on the impeller surface and cannot be scraped and discharged with rotation,leading to empty operation without output.

Excessively large clearance between rotor and shell

Improper matching clearance of internal components causes air leakage inside the unloader.Upward air backflow is generated,which blows the light powder materials back to the upper hopper.Thus materials cannot fall smoothly and be discharged.

Blockage at feeding inlet

Sundries,fiber impurities and agglomerated materials block the upper feeding port.The passage is blocked so that materials cannot enter the unloader body normally.

Too low rotating speed

The motor speed is insufficient,and the rotor runs too slowly.The material pushing capacity of blades is weak,which cannot transfer and discharge materials effectively during rotation.

Material accumulation and hard blockage in internal cavity

Long-term accumulated old materials harden inside the unloader,forming a fixed material layer.The rotor only idles inside without stirring and transporting new materials.

Solutions

Install vibrators or air cannons on the hopper to eliminate material arching and bridging.

Dry the conveyed materials properly to reduce viscosity and wall sticking phenomenon.

Adjust the assembly clearance of rotor and shell to solve internal air backflow problem.

Clean foreign matters and lumps at the feeding inlet to keep the feeding passage unobstructed.

Check motor and reducer parameters,adjust rotating speed to the rated working range.

Disassemble the unloader and clean hardened accumulated materials inside the cavity thoroughly.

References

1.GB/T 7714

Li X,Zhang S.Fault Analysis of No Material Discharge of Star Unloader Under Normal Operation[J].Bulk Material Handling,2022,45(3):83-87.

2.MLA

Li,Xin,and Shuai Zhang."Fault Analysis of No Material Discharge of Star Unloader Under Normal Operation."Bulk Material Handling,vol.45,no.3,2022,pp.83-87.

3.APA

Li,X.,&Zhang,S.(2022).Fault analysis of no material discharge of star unloader under normal operation.Bulk Material Handling,45(3),83-87.