We often see in the sample of the heat pump oil pump model after the addition of A, B, C characters, which means that the pump impeller diameter is cut, is a variation of the pump .A, B, C, said impeller cutting different degrees. According to the classical theory, a series of formulas are deduced according to the similarity theory, that is, the flow rate is proportional to the square of the impeller diameter, and the lift is proportional to the square root of the impeller diameter, and the power and the cubic of the impeller diameter According to the latest information, (6) than the speed of 66 to 212 between the verification by the typical pump, relatively close to the actual, as shown in Table 2-4, of course, due to the experimental pump As yet only as an estimate, it is better to use the classic one, two, three times to estimate. If you want to make a comparison, may wish to use a variety of methods to compare. If found and the actual difference is too much The accumulation of data, perhaps the law of perfect contrast, will play a catalytic role.Also developed a new cutting method, that is, only the outer diameter of the blade, without cutting the front and rear cover of the impeller or rear cover than the front cover The reason is that if both the front and the rear covers of the impeller are cut off, the gap between the impeller and the casing of the heat transfer oil pump becomes larger, resulting in hydraulic losses such as circulation, eddy current and secondary flow in the flow between the impeller and the pump casing. It shows that the cutting method has less head descent, and the efficiency does not decrease when the cutting amount is less than 5%. The specific conversion formula can refer to the following formula: Q '/ Q = (D'2 / D2) 1.8 H' / H = '2 / D2) 2.3 In addition, no matter what method, in order to cut the efficiency will not decline too much, the amount of cutting to be controlled.