Inspection, Inspection and Complementary Testing 1 Inspection at the manufacturer's factory The purchaser will specify in the order to inspect the valve at the valve manufacturer and to witness the inspection and testing of the valve. During the execution of the purchase contract, the Buyer Inspector may enter any part of the manufacturing plant related to valve manufacture at any time. 2 Inspection outside the valve manufacturer When the purchaser specifies that the inspection includes parts of the housing manufactured outside the valve manufacturer, these parts should be checked by the buyer at the place of manufacture. 3 Inspection Notification When the inspection by the buyer is required, the valve manufacturer shall notify the buyer at the address listed on the order 5 working days prior to the required valve test and required supplementary inspection or inspection. If the factory inspection is needed, the valve manufacturer shall also notify the buyer at 5 days in advance when and where it can inspect the shell parts manufactured outside the valve factory. 4 Scope of inspection Scope of inspection can be specified in the order, unless otherwise indicated, the inspection should be limited to the following. a, in the assembly process to check the valve to ensure compliance with the provisions of the order. Inspection may include the use of prescribed non-destructive testing methods. b. Witness the required and prescribed pressure tests and inspections on site. C Field witness any additional testing (see Section 2.6). d. Review processing records and NDT records (including specified ray inspection records). 5 Inspection 1. The valve manufacturer shall perform a visual inspection of all castings of valve bodies, bonnets and seals to ensure compliance with valve MSSSP-55. 2. The valve manufacturer shall inspect each valve to ensure compliance with this International Standard and the referenced procurement specifications (eg APl 600, see section 1.2.2). 3. All inspections shall be conducted in accordance with written procedures prepared in accordance with the appropriate standards. 6 Supplementary Testing Various supplementary tests are to be carried out only in the order and only in the specified range. Magnetic powder test, ray test, liquid penetrant test and ultrasonic test of cast steel or forgings shall comply with Chapter 8 of ASME Bl6.34 or buyer's own procedures and acceptance criteria, if any. These inspections should be carried out by the valve manufacturer in the presence of the buyer inspector. 7 pressure test 1. Test site pressure test by the valve manufacturer in the valve factory. 2. Test Equipment The equipment used by the valve manufacturer to perform the required pressure test shall not apply external forces that affect the seat seal. If the end clamp test device is used, the valve manufacturer shall verify that the test device does not affect the sealing performance of the tested valve. End clamps are suitable for valves fitted between mating flanges, such as wafer-type check valves and wafer-type butterfly valves. 3. Necessary Tests 1. Each valve shall be subjected to the pressure tests listed in Table 1-A or Table 1-B in accordance with written procedures prepared in accordance with this standard. 2. Unless otherwise stated in the order, the valve on which the seal is to be made is to be hermetically sealed by the manufacturer for either high pressure or low pressure. 3. Specifications of NPS or less 4 Pressure ratings of less than or equal to ASME Class 1500 valves and sizes greater than NP5 4 Valves rated less than or equal to AsME 600 pounds should be tested in accordance with Table l-A. 4. Specifications of NPS or less 4 Pressure ratings greater than AsME 1500 pounds of valves and sizes greater than NPS 4 Valves rated at 600 pounds or more of ASME pressure shall be tested in accordance with Table 1-B. 4. High Pressure Seal Tests As shown in Table 1-A and Table 1-B, there are several types of valves that require high pressure seal tests. For some types of valves, high pressure sealing tests are optional, as shown in Tables 1A-A and B-B. However, these valves are still required to pass the high pressure seal test as a design of the valve seal structure. 5. High-pressure gas shell test When specified in the order, high-pressure gas shell test should be carried out. High-pressure gas shell test should be carried out after the hydraulic shell test, and have the appropriate safety precautions, gas shell test pressure should be 100 (30 ℃) 110% of the maximum allowable pressure or as specified in the order No visible leaks allowed. 8. Pressure Test Methods 1. General 1. For valves with a structure that allows emergency or additional filling of the sealing surface or packing with sealing grease, the injection system shall be empty and ineffective at the time of the test. Oil seals Excluding plug valves. 2. When the liquid is tested as a test medium, there should be essentially no air inside the valve. 3. The required protective coating, such as paint, may mask surface defects. No coatings of this type shall be applied to any surface prior to inspection and pressure testing (phosphating or similar chemical treatments are acceptable for protecting valve surfaces and may even be performed prior to testing as long as such treatments do not obscure defects such as porosity ). 4. When the gate valve, plug valve and ball valve seal test, the valve manufacturer should adopt such a test method, in the valve seat and valve cover cavity filled with medium and pressurized. This ensures that no leakage of the sealing surface is not detected due to gradual filling of the media with the test site and pressurization. 5. When the valve seal test, the valve manufacturer's test method should be able to ensure that no excessive force to close the valve. The applied closing force can be determined from the appropriate value for MSSSP - 91, but in no case should this force exceed the value widely advertised by the valve manufacturer. 2. Shell Tests In addition to the conditions listed in 4.3.2, the shell test shall be to pressurize the fitted valve. At this point, the valve closed at both ends, the valve part of the open, in addition to the bellows sealed valve, the packing gland pressed enough to maintain the test pressure, which also tested the stuffing box. Non-adjustable shaft seals (O-rings, single washers, etc.) should be free from leakage in the shell test. 3. Upper Seal Test 1. All valves that have the upper seal performance shall be subjected to the upper seal test with the exception of bellows sealed valves. The test should be to have been installed within the valve pressure, this time, the valve closed at both ends, gland packing loose. The upper seal test may be carried out immediately after the shell test. The upper seal test shall be followed by re-packing of the packing gland. Valve manufacturers should not seal the valve on the success of the test, as the recommended valve pressure can be loaded or replaced when filling. 2. The purchaser and the valve manufacturer agree that the upper seal test and the shell test may be combined when using a volumetric meter to detect leaks in the housing and upper seal. In this test, the filler should be relaxed. The valve manufacturer is responsible for verifying that the valve is not leaking of packing at a rated pressure of 100T (38c). 4. Low pressure seal test 1. Low pressure seal test, the sealing surface should be kept clean, no oil, no grease and sealing grease. To prevent scratches, apply a layer of oil film that is not heavier than kerosene on the sealing surface. The requirements of this section do not apply to valves that lubricate the primary seal (eg, oil-tight stopcocks). 2. Low-pressure seal test should be carried out by one of the following methods. a. For valves designed to be bi-directional, with the exception of a dual-use valve and a stop valve, pressure shall be applied at each end of the shut-off valve and open to the atmosphere at the open end to check for leakage at the open end. For the cut-off valve, the valve should be pressurized under the pressure direction. Valves marked as such with wells designed to be unidirectional shall be pressurized only at the inlet. For check valve. Pressurize at the outlet. Any leaks behind the valve seat, seat ring or through the valve disc should be checked at the open end of the valve, sealed with water or smeared with soap and water or similar solution Sealing (valve flap, valve seat and seat ring behind) , Observe the bubbles that pop up from here. In addition, leak detection may be performed using a drain gassing unit, as determined by the purchaser and the manufacturer, provided that measurable leaks correspond to the values ​​given in Table s. Air bubbles may only be tested on valves larger than NPS 2 with the purchaser's consent. b. For interrupting a discharge valve, one end of the valve should be pressurized through the valve orifice. Leakage into the valve chamber between seats should be checked at the stuffing box (at this point, without packing) or through the discharge hole between the seats. Valve test, the stem should be in the vertical position. Leakage rate at the seal should not exceed Table 5. NOTE For wedge single-gate (rigid or flexible) gate valves, pressure-test air or gas is enclosed in the body cavity between the two sealing straps and then either sealed with water or smeared with soap and water or similar solution for leak detection, This low-pressure seal test method is not recognized. 3. If there is a discharge fitting on the valve body and the valve is tested in accordance with 8.4.2, press ASMEBl. 20.1 Joints shall not exceed NPS 1/2. Before the valve is shipped, plug the discharge fitting with a screw-on (equivalent to ASME B16.11) of the equivalent valve housing. 4. Butterfly valves (API 609 Class A valves) designed with 125 lb. or 150 lb. flanges with a sealed or elastomeric liner are only required to perform a seal test in one direction. For other flexible sealing butterfly valve (APl 609B class valve), requires two-way seal test. For valves with a preferred flow direction, the non-preferred seal test shall be conducted in this direction with a reduced pressure differential rating. 5. High Pressure Seal Test 1. The high pressure seal test method is the same as the low pressure seal test except when the test medium is a liquid. Leaks should be detected as droplets rather than as described in Section 2. 9. Valve Certificate of Compliance and Repeated Testing 1. Certificate of Conformity When specified in the order, the valve manufacturer shall provide the purchaser with a certificate certifying that the valve product complies with the order. 9.2 Repeated Test Unless the order specified by the buyer seized, the completion of the valve does not require repeated testing. When the manufacturer provides Ding valve has passed the requirements of this standard passed the inspection, testing and inspection, the buyer inspector can give up the requirements of repeated testing. Repeat test, the valve has been painted do not need to remove the paint. Stock valves should be commercially cleaned prior to repeated testing and shipping. Search Keyword: 德 喜 阀门 阀
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