Multi-stage axial flow submerged pump with long shaft and method for conveying phosgene

Abstract

The invention relates to a multi-stage axial flow submerged pump with a long shaft and a method for conveying phosgene, which are mainly used for pressurizing and conveying the phosgene or chlorine gas. The submerged pump is provided with an inducer (1), a primary impeller (2), a secondary impeller (5), an auxiliary sliding bearing and shaft sleeve (6), a lower main sliding bearing and shaft sleeve (8), an upper main sliding bearing and shaft sleeve (10), a seal cavity (19) and a bearing bracket (28). The lower end of a packing box (13) is provided with an emergency seal rubber pneumatic bag (17); a double-end face mechanical seal (22) is sleeved on a pump shaft (30); a radial balancing hole (37) is arranged on the impeller; and the auxiliary sliding bearing and shaft sleeve (6) is made from silicon carbide. When both of the mechanical seal and the packing seal become invalid, high pressure nitrogen gas ensures that the emergency seal rubber pneumatic bag (17) is inflated to clasp theshaft so as to quickly block leakage of the conveyed phosgene.

Description

technical field [0001] The invention relates to a long-axis multi-stage axial flow down pump and a method for pressurizing and transporting phosgene or chlorine gas. Background technique [0002] At present, domestic isocyanate and other industries use shielded pumps imported or produced by joint ventures for pressurized transportation of toxic, harmful or corrosive liquids such as phosgene and chlorine. Practice has proved that the disadvantages of the pump are as follows: ① strict requirements on medium inlet pressure, outlet pressure, temperature and cleanliness; ② high requirements on cavitation allowance; , ⑤ short suction. Vertical vane pumps used to transport flammable, explosive, highly toxic and other harmful chemical liquids, in order to ensure safe and reliable transport medium and prevent leakage, have strict requirements on the shaft seal of the pump, that is, the seal should achieve zero escape, This is difficult to achieve with ordinary mechanical seals. At...

AI Technical Summary

Problems solved by technology

Practice has proved that the disadvantages of the pump are as follows: ① strict requirements on medium inlet pressure, outlet pressure, temperature and cleanliness; ② high requirements on cavitation allowance; , ⑤ short suction

Vertical vane pumps used to transport flammable, explosive, highly toxic and other harmful chemical liquids, in order to ensure safe and reliable transport medium and prevent leakage, have strict requirements on the shaft seal of the pump, that is, the seal should achieve zero escape, This is difficult to achieve with ordinary mechanical seals

At present, there is a kind of submerged pump that proposes to use gas for sealing. It passes sealing gas into the sealing box. The emergency sealing protection of the main seal failure is realized through the rubber sealing bag. This kind of gas sealing is not suitable for other conditions. vertical pump used

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