| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a urea water pump decreasing wear or adhesion of a sliding part by decreasing urea crystal deposits. <P>SOLUTION: A groove part 53 is formed between an impeller 27 and a pump case 24 and a pump cover 25. Therefore, part of urea water flowing through a pump passage 29 is stored in the groove part 53. The moisture of the urea water stored in the groove part 53 is less apt to evaporate than other parts. As a result, urea crystal is less apt to deposit between the sliding impeller 27 and the pump case 24 and the pump cover 25. The groove part 53 is annularly formed. Hence, the urea water introduced into the groove part 53 is equalized circumferentially in the impeller 27 the pressure between the impeller 27 and the pump case 24 and the pump cover 25. This reduces the inclination of the impeller 27 and a local wear of the impeller 27 due to the inclination of the impeller 27. <P>COPYRIGHT: (C)2009,JPO&INPIT |
