1. Purpose
1.1 This global specification defines the proper use of shipping covers supplied on Samson valves for pressure testing cold box process circuits. It is important that cold box fabricators follow these instructions so that the valves are not damaged and that the work associated with pressure testing is optimized.
2. Scope
2.1 This specification applies to all equipment, cold boxes, pump boxes, skids, and fabricated systems on which Samson cryogenic control valves are provided with shipping covers. It applies to fabrication work done by Air Products or third party fabricators doing work on Air Products’ behalf.
3. Related documents
3.1 Air Products Engineering Documents 4WPS-VALV11 Proper Handling and Weather Protection of Samson Cryogenic Globe Cold Box Valves with Bellows Seals
3.2 Samson Documents EB 8093 EN Mounting and Operating Instructions
3.3 Samson Contact Information SAMSON Controls, Inc. SAMSON Controls AG 4111 Cedar Boulevard Weismullerstrabe 3 Baytown, TX 77520-8588 D-60314 (281) 383-3677 Frankfurt am Main www.samson@samson-usa.com Germany 10 1901 011 49 694 009 www.samson.de
4. definitions
4.1 None
5. REQUIREMENTS
5.1 Shipping covers provided with Samson cold box valves are designed to keep rainwater and debris from entering the upper valve extension during shipment and cold box construction/erection.
5.2 When valves are shipped from the Samson factory, shipping covers are installed on the lower bonnet flange with an O-ring to provide a weather-tight seal. A plastic cover is inserted in the top of the cover and an O-ring or plastic washer is installed under the stem-retaining nut.
5.3 The shipping cover, as installed at the factory, also keeps the valve plug off the seat in a partially open position. This allows the valve to be welded in-line with a flowing internal purge. It also allows the valve to pass the pressure test fluid to the downstream piping and permits free flow of cold box shipping purge gas. If the valve is a pressure test boundary valve, it may need to be closed to isolate the upstream and downstream pressure circuits. To close the valve, the shipping cover must be removed and the actuator installed.
Note: The manufacturer’s instructions must be followed very carefully to avoid damaging the internal bellows assembly. If manufacturer’s instruction manuals are not available, contact Samson directly.
5.4 Shipping covers are not designed to be a pressure-containing component. The shipping covers are designed to withstand the stem thrust generated when the valve body is pressurized. The upper extension area is isolated from the pressure in the valve body by the isolating bellows. For that reason, the shipping cover shall remain in place for pressure testing of the piping circuits unless the valve must be in the closed position for the pressure test.
5.5 Shipping covers are marked with the maximum pressure test pressure allowed for use with the covers in place. There are two shipping cover designs: 30 bar g (450 psig) and 90 bar g (1200 psig). These pressure values are for the maximum pressures allowed inside the valve body with the cover plates installed.
5.6 If the shipping covers are removed, they shall be reinstalled with the plastic washer under the stem retaining nut, the large O-ring between the shipping cover and the lower bonnet flange and the plastic cover inserted to prevent any moisture from entering the upper extension area. Make sure the bonnet test connection is secure as well.
5.7 Sometimes it is preferred to ship the cold box with the valve bonnets installed in place of the shipping covers. This can be done by assembling the upper stem assembly, installing the bonnet flange gasket provided, applying the proper torque to the bonnet bolts and fully seating the packing nut.
Note: The packing design is a live loaded type that is designed to have the packing nut fully seated to apply the appropriate packing load on the stem.
Note: The manufacturer’s instructions must be followed very carefully to avoid damaging the internal bellows assembly. If manufacturer’s instruction manuals are not available, contact Samson directly at any of the Samson contact numbers, or if you have access to the Air Products intranet, obtain instructions and Samson support phone numbers on the Process Control Homepage (http://web2.apci.com/geo_procctl/docs/instrum/samson.htm).
5.8 Additional weather protection is required during shipping and outdoor storage to guarantee no moisture egress into the upper extension area. Whether the cold box is shipped with shipping covers or bonnets installed, the extension shall be wrapped with heavy plastic and securely fastened as appropriate for the shipment method and duration.
Note: Consideration shall be taken in wrapping the valves so that the wrapping remains rainproof during transit as well as on site after the cold box is placed in its vertical position.
5.9 Removal of the weather protection and shipping cover shall only be done when actuators are ready to be installed.
5.10 If shipping covers are not used because the bonnets were installed, they shall be bagged, tagged, and sent to the site complete with the large O-rings, plastic cover, and stem-retaining nut for possible use in the future.