Common Misconception Regarding 150# and 300# Valve Flange Thickness

There exists a common misconception in the minds of end-users of valves, with regard to the flange thickness of 150# and 300# valves. This is due to the fact that the ASME B16.5 standard treats these two pressure class valve flanges differently when compared to the other higher pressure class valve flanges. The flange thicknesses in the case of 150# and 300# valve flanges are required to be in accordance with the flanged fittings table and are lesser than the flange thickness for the corresponding class pipeline flanges. Sometimes, end users are confused as to whether they should accept valves with thinner flanges than the corresponding pipeline flange thicknesses.

The reason for the confusion stems from the fact that the explanation for this anomaly is given in section 6.2.2 of ASME B16.34 standard and not in ASME B16.5 standard. Section 6.2.2 of ASME B16.34 states that “Flanged ends shall be prepared with flange facing, nut bearing surface, outside diameter, thickness, and drilling in accordance with ASME B16.5 requirements for
(a) flanged fittings for Class 150 and 300 valves
(b) flanges for Class 600 and higher valves”

In light of the above, it is important to understand that Class 150# and 300# valve flanges shall follow the flanged fittings table and shall have lesser flange thicknesses compared to the corresponding pipeline flanges.

NON-SLAM CHECK VALVE- NEW PRODUCT FROM KAVAATA VALVES

KAVAATA is proud  to announce our newly developed product NON-SLAM CHECK VALVE. The valve can be supplied in sizes like 2″, 3″ & 4″. The materials of construction are ASTM A216 Gr WCB (CS), ASTM A351 Gr CF8 (SS304) and ASTM A351 Gr CF8M (SS316).

These valves can be used in the following applications:

  • Gas and liquid pipelines – Gas export facilities
  • Water and steam systems – Product tank farms
  • Cooling towers – Gas storage caverns
  • Water treatment – Mine dewatering

Non-slam check valves are also used in similar applications throughout the chemical processing industry, steam condensate systems and in the power generation industry.

One of the primary advantages of non-slam check valves is their ability to effectively prevent water hammer  therefore, eliminate resultant pressure swings, vibrations, and damage.

 

Timely Procurement of Valves- A Challenge for the Project Manager

Procurement of valves for a project presents itself as a challenge to the Project manager. This is because of the variety of valves required in a project- be it ball valves (manual or actuated, floating or trunnion mounted, two way or multiport), gate valves (rising stem, non-rising stem or knife gate valve), check valves (swing check valve, non-slam check valve or lift check valve), globe valves (regular or Y type globe valve), butterfly valves (lug type or flanged type), plug valves (two way or multiport, manual or actuated), hydraulic valve for high pressure, pinch valves for slurry and the list goes on.  Further, there is a classification based on the material of construction (WCB, CF8, CF8M etc.) and end connections (screwed end- BSP, NPT, BSPT, NPTF etc, socket weld end, butt weld end, and flanged end). Flanged end valves are further classified into pressure classes like 150#, 300#, 600#, PN10, PN16 etc. and country wise standards like ASA, DIN, JIS, BS, EN etc. Of course, size of valves range from 1/4″ to 60″ and above- Phew!

The sheer variety of valves makes it impossible for one company to manufacture all types. Unlike hardware items like bolts, nuts, pipes etc. which are normally available ex-stock, it is impossible for any one company to maintain an inventory of all types of valves. Valve requirement, quantity, size, and type, typically undergoes a number of changes as the project implementation progresses. Hence, the final list of valves required is available only as the pipeline work nears the end. This leaves the project manager very less time for the ordering and procurement of valves. The project manager has to rely on his project a consultant’s recommendation for supplier selection or scout for new manufacturers. The tender process, technical and commercial negotiation and final order generation take up a good chunk of the available time.

Valve manufacturers are always at the receiving end as the time allotted for supply is much less than what is normally required. Valve manufacturers knowingly accept L-D Clause terms, like a discount, while accepting an order. Valve industry is not looked upon as a manufacturing entity with its own set of problems and lead time requirements. This is mainly because the ratio of the total cost of valves to the project cost is very small. The fragmented and specialized nature of manufacturing ensures that valve manufacturers remain small compared to the customer size and hence are not accorded any importance.  Valve manufacturing is a batch process and not a continuous high volume process. What is forgotten is that a delay in supply of valves can bring the entire project implementation to a halt and lead to huge losses. Foundries who supply castings to valve manufacturers work under huge time constraints. Sometimes there are casting defects which can undermine the quality of valves. These show up at the very end of the manufacturing cycle at the valve testing stage and brings more misery to valve manufacturers. Rework, rejection or replacements are required which further delays valve supplies. To add to the misery, sometimes, third-party inspection agencies appointed by customers, do not have inspectors available to conduct a timely inspection. This leads to further delays.

In view of the above, it is imperative that project consultants, project managers, and customers allot sufficient time, typically 6- 8 weeks for good quality valve manufacturing.  Some understanding of the typical problems faced by valve manufacturers will go a long way in early ordering for valves and reduce project delays. It is hoped that this post shall help all concerned to  E-Valve.

 

Seat Material Selection in Ball Valves

Seat material selection in ball valves poses a challenge to most end users in the industry. This is because most users are masters of their domain but lack the technical information to make the correct seat material selection. In this blog, we shall present the required information to help such users.

Generally, PTFE (Poly tetra fluoro ethylene) is the most common seat material used in ball valves. This is because PTFE is chemically compatible with most chemicals and has a very low co-efficient of friction. This allows ball valves to be operated with ease. PTFE can work at 69 Kg/ sq. cm in the temperature range -40 deg C to 90 deg C. The maximum temperature this seat material can withstand is 200 deg C at pressures up to 15 Kg/ sq. cm.

For higher temperatures up to 250 deg C and pressures up to 15 Kg/ sq. cm, Carbon Filled PTFE grades can be used. Similarly, Glass-filled PTFE grades can be used for higher pressures up to 100 Kg/ sq. cm at room temperature.

In case of valves for hydraulic applications at room temperature and pressures up to 400 Kg/ sq. cm, POM (Acetal Resin) seats can be used economically.

In applications requiring the seat material to withstand both higher temperatures (150 deg C) and pressures up to 400 Kg/ sq. cm, PEEK seats can be used. Virgin PEEK, as well as carbon filled PEEK grades, are available. However, PEEK seats are very expensive and should be specified only in very critical applications.

For severe service, valves can be supplied with metal seats. Various combination of metal seat types are available for temperature ranges from 350 deg. C to 650 deg C. The advantage of metal seats is that there is practically no pressure constraints. Moreover, these valves can work very well with abrasive media.

KAVAATA valves are manufactured with all the above-mentioned seat materials and can be supplied against specific customer requirements. KAVAATA can supply metal seated valves with Class V and Class VI leakage rates.