Recent content by valvit

For 10K no. For other pressure ratings yes. See Tables 67-72, as well as Table 4 for tolerances. Valvit

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...

API 6A PR2 test specifies 20 cycles at both minimum and maximum rated temperature. Valvit

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

Per API, if you seal weld the ring, it is not a renewable seat. To be a renewable seat, it must be threaded or pressed in. 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...

I would agree. Since the spring is jacketed by the PTFE, you should not experience galvanic corrosion. Valvit

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...

I agree with reverman, both the body marking in 4.2 and the nameplate marking in 4.3 are mandatory (as well as all of section 4). Valvit

The number of thermocouples required is not additive. You are correct, 16 thermocouples are required. Valvit

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...

LittleInch, Yes, it is a spring relief valve. Commonly 1/2" NPT or ISO 228 parallel thread. Valvit