What are the problems encountered during the installation of flanges and clamp connections?
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During a technical discussion, the client said that installing clamped connections is more complicated than installing flanged connections. I would appreciate some guidance on the differences between flanged and clamped connections, as well as the issues that may arise during installation, such as positioning those with metal wound gaskets... Thank you
What matters is the length of the bolts; if there is even a slight deviation, it will be very difficult to insert the bolts, especially those that correspond to the two or four bolt holes in the valve itself.
Following the standards, flange installation is not difficult; one can refer to GB50235. The following points should be taken into account when manufacturing and installing flanges: 1. The deviation of the flange holes located at the mid-span, especially in the case of clamped installations; 2. The parallelism of the flange surfaces; 3. The concentricity of the flange axes; 4. The protection of the flange surfaces; 5. The clearance dimensions of the flanges
Is there a specific solution? Thank you
Is there a good way to maintain concentricity?
Differences between wafer-type and flange-type: The mating flanges are different; the key difference lies in the inner diameter. Wafer-type butterfly valves use special flanges that have two inner diameters – the smaller diameter is used to hold the butterfly valve in place, thus securing it. The bolts used are much longer than those in flange-type valves, as they pass through two flanges on opposite sides (the bolts that connect the flanges on either side of the valve body). As for gaskets, the choice depends on the operating conditions, and they are the same as those used in flange-type valves
In fact, the wafer-type valve, flanges, gaskets, and bolts/nuts can be combined into one unit; once secured, it can be delivered to the customer for use. It actually has to do with the tolerance control in on-site construction: In the flange type, there are two separate connections, and bolt tightening can be used to compensate for that ； Clamped type: fixed at the front, with an opening at the back.
I think it’s a problem with construction tolerance control. Clamped valves require a higher level of precision in installation on pipelines compared to flanged valves, especially regarding their perpendicularity to the pipeline.
It is important to control the flanges properly; for the clamp-type design, the value must be positive, as it is the two flanges that hold it together