A.15% B.16% C.17% D.18%
A.1/6~1/4圈 B.1/4~1/2圈 C.1/2~1圈 D.1~2圈
A.彈簧間有結(jié)晶 B.泵抽空后密封破壞 C.介質(zhì)不清潔 D.機(jī)械密封冷卻效果不好
A.截止閥 B.球閥 C.減壓閥 D.蝶閥