フランジボルトパターンとは?

フランジは配管システムの重要なコンポーネントです, パイプを接続するために使用されます, バルブ, パンプス, およびその他の機器. One of the most important aspects of flange design is the ボルトパターン—the arrangement of bolt holes around the flange. The bolt pattern ensures that the flange aligns correctly with its mating component and maintains a tight, leak-proof seal when bolted together.

この記事では, we will explain what flange bolt patterns are, how they are measured, why they matter, and how to select the correct bolt pattern for your system. This guide is brought to you by ササフランジ, your expert manufacturer of standardized and custom flanges for global applications.

What Is a Flange Bolt Pattern?

あ flange bolt pattern を指します ボルト穴の数, の diameter of the bolt circle, そして間隔 between each bolt hole on a flange. It determines how the flange mates with another flange and how the bolts are positioned to create an even, secure seal.

The bolt pattern must be precisely matched between mating flanges. If the bolt holes do not align perfectly, the connection cannot be assembled or sealed properly. That’s why understanding bolt patterns is essential in any piping project.

ササフランジ manufactures flanges with highly accurate bolt hole patterns that conform to global standards such as ASME B16.5, EN 1092-1, そして JIS B2220.

Components of a Flange Bolt Pattern

To fully understand a bolt pattern, you need to be familiar with the following elements:

1. ボルト穴数

This refers to how many bolts are required to fasten the flange. The number varies depending on the flange size and pressure rating.

2. ボルト円直径 (BCD)

Also called the Pitch Circle Diameter (PCD), it is the diameter of the imaginary circle that passes through the center of all the bolt holes.

3. Bolt Hole Size

The diameter of each bolt hole, which must match the size of the bolts used.

4. Bolt Hole Spacing

The angular distance between adjacent bolt holes, usually symmetrical around the flange.

All these factors must match between two flanges for them to connect securely. で ササフランジ, we use precision CNC machining to ensure bolt hole alignment and compatibility.

Common Flange Standards and Bolt Patterns

Different international standards specify bolt patterns differently. The most commonly referenced include:

ASME B16.5 (used in the USA)
EN 1092-1 (used in Europe)
JIS B2220 (used in Japan)
ゴスト (used in Russia)

Each standard defines bolt patterns for various nominal sizes (NPS または DN) そして 圧力クラス (Class or PN).

例えば, an ASME 6-inch Class 150 flange typically has:

8 ボルト穴
A bolt circle diameter of 190.5 mm
Bolt holes sized for 19 mm bolts

This is different from a DIN PN16 flange of the same nominal size. それで, bolt pattern compatibility must be checked carefully when sourcing or designing flanges.

Why Bolt Patterns Matter

Bolt patterns are critical for several reasons:

Mechanical Stability: An even bolt pattern distributes pressure uniformly to avoid flange warping or gasket failure.
Sealing Integrity: Proper bolt placement ensures the gasket is compressed evenly, 漏れのリスクを軽減する.
標準化: Consistent patterns enable interchangeability between different manufacturers and systems.
Installation Efficiency: Accurate patterns make flange assembly faster and easier on site.

Improper bolt alignment can cause serious operational and safety issues. それが理由です ササフランジ invests in high-precision manufacturing to ensure bolt pattern accuracy.

How to Measure a Flange Bolt Pattern

To measure a bolt pattern on a flange:

Count the bolt holes
Measure the ボルト円径 (BCD/PCD)
Measure the diameter of each bolt hole
Check the bolt spacing (angle or linear distance between holes)

For flanges with even hole counts, measure from center-to-center across the flange. For odd hole counts, を測定する diameter of the imaginary circle through the centers of the holes.

These measurements help identify the correct standard and size of the flange.

不明な場合は, you can always contact ササフランジ with your measurements, and our team will help match or design the correct flange for your application.

Bolt Pattern Variations by Pressure Class

As the pressure class increases, bolt patterns often change to accommodate larger or more bolts for greater strength. 例えば:

A 4-inch flange in クラス 150 may have 8 ボルト
A 4-inch flange in クラス 300 may have 8 larger bolts and a different BCD
A 4-inch flange in クラス 600 may increase to 12 ボルト

This ensures the flange can withstand higher internal pressures without leakage or deformation.

ササフランジ offers all flange sizes across various pressure classes, with consistent and accurate bolt patterns that follow international norms.

Custom Bolt Patterns

While most projects use standard flanges, some systems require custom bolt patterns due to retrofitting, space constraints, or special designs. そのような場合には:

Flanges can be drilled with non-standard hole counts
Hole positions can be offset or rotated
Custom templates can be followed for one-off solutions

ササフランジ specializes in custom flange fabrication. We can machine flanges with special bolt patterns to match legacy systems or new design requirements.

Applications of Bolt Pattern Knowledge

Understanding flange bolt patterns is essential in:

Piping system design
Maintenance and repair
Procurement and sourcing
Engineering drawing interpretation

With the right knowledge, engineers and procurement teams can avoid costly mismatches and installation delays.

結論

の flange bolt pattern is a fundamental aspect of flange design, affecting everything from installation to sealing performance. Whether you’re dealing with ASME, DIN, またはカスタムフランジ, getting the bolt pattern right ensures your piping system operates efficiently and safely.

で ササフランジ, we provide flanges with precisely machined bolt patterns that meet or exceed global standards. Whether you’re sourcing standard flanges or need a custom pattern for a specialized application, ササフランジ has the technical expertise and manufacturing capability to deliver exactly what your project demands.

選ぶ ササフランジ—where precision meets performance in every bolt hole.