TOV,
All valves must open or close with pressure in the pipeline. With the valve in the closed position, and full pressure (MAOP) on one side of the valve, and low to zero pressure on the other side, this is known as full differential pressure (aka delta-P). Most valves, when opening against...
Most manufacturers will report MAST at Maximum Allowable Operating Pressure (MAOP). At maximum temperature rating, the MAOP is lower. If the valve MAST is lowest at maximum temperature and the coincident pressure, that is the value you should report.
Valvit
You've answered the question for yourself. 17-4 has higher SMYS and UTS than anything in the austenitic family, so parts of the same size will be stronger and will have higher allowable stress values. If you have high sulfur content, you need to be concerned with H2S content. 17-4 is highly...
Lip seals need a very smooth surface finish to provide an effective seal. Any corrosion in the seal area will allow the lip seal to leak, thus the need for the corrosion protection. The lip seal itself, should use a spring made from a corrosion resistant material.
Valvit
I use Roarks 6th Ed. This formula is just for the portion of the stem that is in the double-D (opposing flat sides) shape. The section below the double D is (probably) circular in section and needs to be evaluated separately. The below is the formula for non-circular section under pure...
@CKchi...
RPTFE may have a maximum temperature range of 200C, and it may also be suitable for Class 600 pressure....but not at the same time. Many manufacturers will answer each question independent of the other...and ignore the fact that because of creep, RPTFE cannot handle higher pressures...
My advice is to be sure you understand how to disassemble anything when it could have a compressed spring. Stop work, and get a maintenance manual from the manufacturer.
Valvit
Best guess is that stands for Extended Buttweld end. Very common for a small diameter forged ball valve like that, to have "integrated" pipe nipples, forged directly with the valve ends. This moves the heat source from field welding away from the body and seat seals, and prevents damage during...
If you are designing for a specific project, a good rule of thumb is to check to see what material the associated piping is made from. If the piping is carbon steel, then your valve can likely be carbon steel as well. If the piping is stainless steel...then your valve may have to be stainless...
I presume you are building a valve to API 6D, since you are referring to DIB-1. For now, B31.3 makes no reference to API 6D as an approved valve standard, but ASME committee are including it for B31.3-2015 revision, so thats good news. Also note the title of 24th Edition of 6D now includes...
There is no standard to refer to when determining the bore to sphere ratio. I agree it is true that the rest of the valve design is performed after the bore/seat design is complete...and in that manner, it can be said that the rest of the design is dependent on the bore...but to Mike's point...
An angle valve is suitable for 2-phase flow because if you fill the pipe halfway with water, the other half is filled with air, and you have 2-phase flow.
If you connect 220V-3 phase electric to the pipe, then you are allowed to multiply the 3-phase electric to the 2-phase fluid to get 6-phase...
API 598 and API 6D both state that if a valve is equipped with a backseat, it must be tested. ASME B16.34 does not address the topic.
Backseat test is a test on the valve stem...and has nothing to do with the seat test.
If you ordered the valve to be tested in accordance with API 598, and it...