滑道滚球式止回阀主要由阀体、阀盖、阀座、滑道及滚球等组成，其滚球外包覆软密封层，由进、出水口形成的流道与滑道呈30°夹角，阀体内的阀盖表面设有契合滚球的圆弧形凹槽，阀座采用内凹式结构，内设密封垫。该阀滚球外表面及阀座上都设有软密封 ...

主营产品：矿山冶金火电煤化工输灰浆渣组合阀、JSTLCS943TY/G法兰落差式物料阀、HS44W法兰浮瓣式止回阀、JSTV捷斯特安耐特节能 ...

生产橡胶密封件厂家还可能会用到顺丁橡胶（BR）、氯丁橡胶（CR）、丁苯橡胶（SBR）、丁腈橡胶（NBR）以及三元乙丙橡胶（EPDM）等常见再生胶，通过合理利用各种再生橡胶不仅能够减少资源消耗，还有助于环境保护和循环经济的持续发展，提高产品的质量和 ...

The National Board of Revenue (NBR) has sought budget proposals from all concerned to prepare a participatory, pro-people and balanced budget for the next fiscal year (FY26). The NBR usually seeks ...

The National Board of Revenue (NBR) will no longer defer the deadline for submitting income tax returns, which was extended three times from its initial date in November last year. Besides ...

The deadline for income tax return submission, after being extended three times, ended today and will not be extended further this year, the National Board of Revenue (NBR) has announced.

The National Board of Revenue (NBR) plans to amend the existing baggage rules to prevent the misuse of gold import opportunities and is considering imposing additional taxes on jewellers. "There is ...

二、成因分类与解决方案 （一）材料因素1. 生胶类型选择不当 案例：NBR制品硫化后表面发粘 ... （二）配方设计因素1. 硫化体系失衡 案例：EPDM密封件硫化后粘模，分析发现硫磺用量不足（1.0 phr）且促进剂CZ与TMTD比例失调（2:1），导致硫化速度慢、交联度低。