Selection of living flange for glass lined reactor

The selection of the loose flange for the glass lined reactor should comprehensively consider the equipment operating conditions, medium characteristics, installation requirements, and standard specifications. The following are the key points and steps for selection:

1. Clarify the operating parameters

Nominal pressure (PN): Select the flange pressure rating (such as PN6, PN10, PN16) based on the design pressure of the reaction vessel, taking into account the correction of temperature on material strength.

Nominal diameter (DN): Strictly match the interface size of the reaction vessel (such as DN80, DN100).

Working temperature: Glass lined equipment is usually suitable for temperatures ranging from -20 ℃ to 200 ℃. For high temperatures, the temperature resistance of the flange material needs to be checked.

Medium characteristics: Strong acid, strong alkali, or organic solvents should be preferred for corrosion-resistant materials (such as lined stainless steel or 316L).

2. Flange standards and types

International standards: If the equipment is exported, DIN (German standard) or ASME (American standard) flanges can be selected.

Loop flange structure: composed of flange ring and flange/welding ring, ensuring compatibility between flange and enamel layer (commonly used for low carbon steel Q235-B).

3. Selection of sealing surface

Sealing surface form:

Flat (FF): Suitable for low pressure, non harsh working conditions when paired with soft gaskets (such as PTFE coated gaskets).

Convex surface (RF): Universal type, requiring metal winding pads or graphite composite pads.

Concave surface (FM): Paired with convex surface to enhance sealing.

Gasket material: Choose corrosion-resistant materials (such as PTFE, graphite, metal coated pads) according to the medium.

4. Material selection

Flange ring material:

Carbon steel (Q235-B, 20 #): Economical and versatile, surface requires anti-corrosion treatment (such as spraying epoxy resin).

Stainless steel (304, 316L): preferred for highly corrosive media, but at a higher cost.

Welding ring/flanging material: compatible with enamel glass sintering process, usually low carbon steel (such as Q235-B).

5. Key points for installation and maintenance

Alignment accuracy: The sleeve flange needs to ensure that the bolt holes are aligned to avoid installation stress that may cause the enamel layer to break.

Pre tightening force of bolts: Tighten them step by step according to the standard torque to prevent local over tightening and damage to the sealing surface.

Regular inspection: Monitor the corrosion of flange sealing surfaces and aging of gaskets, and replace them in a timely manner.

6. Suppliers and Certification

Choose a supplier with experience in supporting glass lined equipment to ensure that the flange matches the interface of the glass lined reactor.

Verify material reports (such as MTC) and pressure test certificates to comply with TSG 21 "Safety Technical Supervision Regulations for Fixed Pressure Vessels".

Recommended selection process

Confirm interface parameters: Obtain DN from the reactor drawing PN、 Flange standard.

Select sealing surface type: Choose FF/RF/FM based on the corrosiveness and pressure of the medium.

Material combination: carbon steel+anti-corrosion coating (general working conditions) or stainless steel (strong corrosion).

Verify dimensions: Ensure that the flange inner diameter and bolt hole spacing match the reactor flange.

Consulting manufacturers: Customized solutions are required for special operating conditions such as vacuum and high-frequency vibration.

Example selection:

Operating conditions: DN150, PN6100 ℃,

Medium: 20% hydrochloric acid

Selection: HG/T 20592 loose flange (RF surface, Q235-B+PTFE wrapped gasket)+low carbon steel welding ring.

Systematic selection can ensure reliable flange sealing and long service life, while avoiding the failure of the enamel layer in the glass lined reactor due to mechanical stress or corrosion.