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1、浙江大学毕业设计（论文）外文翻译毕业设计（论文）题目： 水解反应釜设计 外文题目:MINIMUM REQUIREMENTS FOR PRESSURE RELIEF VALVES 译文题目： 泄压阀的最低要求 系 （部）： 机 械 系 专业班级：过程装备与控制工程0702 学生姓名： 指导教师： 2010年 9月 27 日MINIMUM REQUIREMENTS FORPRESSURE RELIEF VALVESUG-136(a) Mechanical RequirementsUG-136(a) (1) the design shall incorporate guiding arrangeme
2、nts necessary to ensure consistent operation and tightness.UG-136(a) (2) The spring shall be designed so that the full lift spring compression shall be no greater than 80% of the nominal solid defection. The permanent set of the spring (dened as the difference between the freeheight and height measu
3、red 10 min after the spring has been compressed solid three additional times after presetting at room temperature) shall not exceed 0.5% of the free height.UG-136(a)(3) Each pressure relief valve on air, water over 140F (60C), or steam service shall have a substantial lifting device， which when acti
4、vated will release the seating force on the disk when the pressureRelief valve is subjected to a pressure of at least 75% of the set pressure of the valve. Pilot operated pressure relief valves used on these services shall be provided with either a lifting device as described above or means for conn
5、ecting and applying pressure to the pilot adequate to verify that the moving parts critical to proper operation are free to move.UG-136(a) (4) the seat of a pressure relief valve shall be fastened to the body of the pressure relief valve in such a way that there is no possibility of the seat lifting
6、.UG-136(a) (5) in the design of the body of the pressure relief valve, consideration shall be given to minimizing the effects of deposits.UG-136(a) (6) Pressure relief valves having screwed inlet or outlet connections shall be provided with wrenching surfaces to allow for normal installation without
7、 damaging operating parts.UG-136(a) (7) Means shall be provided in the design of all pressure relief valves for use under this Division for sealing all initial adjustments which can be made without disassembly of the valve. Seals shall be installed by the Manufacturer or Assembler at the time of ini
8、tial adjustment. Seals shall be installed in a manner to prevent changing the adjustment without breaking the seal. For pressure relief valves larger2 Than NPS 1|2 (DN 15), the seal shall serve as a means of identifying the Manufacturer Or Assembler making the initial adjustment.UG-136(a) (8) If the
9、 design of a pressure relief valve is such that liquid can collect on the discharge side of the disk, except as permitted in (a)(9) below, the valve shall be equipped with a drain at the lowest point where liquid can collect (for installation, see UG-135).UG-136(a) (9) Pressure relief valves that ca
10、nnot be equipped with a drain as required in (a) (8) above because of design or application may be used provided:(a) The pressure relief valves are used only on gas service where there is neither liquid discharged from the valve nor liquid formed by condensation on the discharge side of the valve; a
11、nd(b) the pressure relief valves are provided with a cover or discharge piping per UG-135(f) to prevent liquid or other contaminant from entering the discharge side of the valve; and(c) The pressure relief valve is marked FOR GAS SERVICE ONLY in addition to the requirements of UG-129.UG-136(a) (10)
12、for pressure relief valves of the diaphragm type, the space above the diaphragm shall be vented to prevent a buildup of pressure above the diaphragm. Pressure relief valves of the diaphragm type shall be designed so that failure or deterioration of the diaphragm material will not impair the ability
13、of the valve to relieve at the rated capacity.UG-136(b) Material SelectionsUG-136(b) (1) Cast iron seats and disks are not permitted.UG-136(b) (2) Adjacent sliding surfaces such as guides and disks or disk holders shall both be of corrosion resistant material. Springs of corrosion resistant material
14、 or having a corrosion resistant coating are required. The seats and disks of pressure relief valves shall be of suitable material to resist corrosion by the uid to be contained.NOTE: The degree of corrosion resistance, appropriate to the intendedservice, shall be a matter of agreement between the m
15、anufacturer andThe purchaser.UG-136(b)(3) Materials used in bodies and bonnets or yokes shall be listed in Section II and this Division.Carbon and low alloy steel bodies, bonnets, yokes and bolting (UG-20) subject to in-service temperatures colder than 20F(30C) shall meet the requirements of UCS-66, unless exempted by the following.(a) The coincident ratio dened in Fig. UCS-66.1 is 0.35 or less.(b) The material(s) is exempted from impact testing per Fig. UCS-66.UG-136(b) (4) Materials used in nozzles, disks, and other parts contained within the external structure of the pressure reli
