Horizontal tank saddle support

When selecting saddle supports for horizontal vessels, weight indeed needs to be taken into consideration, but it’s not just the weight issue. The main differences between light and heavy saddle-type supports lie in their structural strength, the range of loads they can handle, and the applications for which they are suitable: Light supports are typically used in conditions of normal temperature and pressure without vibrations, whereas heavy supports are more suitable for environments with high pressure, high temperatures, or vibrations ； When selecting, factors such as container diameter, wall thickness, and medium properties also need to be considered; it is recommended to refer to the load calculation table in standard JB/T4712 ； In actual engineering projects, we generally determine the type of support by comprehensively considering the total weight of the container, the operating weight (weight when filled with water), as well as wind and seismic loads. It is best to have the design firm conduct professional calculations when making a specific selection, as this is a more reliable approach.

It is also necessary to check whether the stresses at various locations of the cylinder exceed the allowable limits. Sometimes, thin-walled equipment can use heavy saddles to avoid thickening the wall thickness of the cylinder.

It needs to be calculated based on a horizontal container.

The strength calculation is to be carried out based on the saddle in the horizontal container.

The choice between a light-type (Type A) or heavy-type (Type B) saddle support for horizontal vessels is determined primarily by the total load (weight) that the support must bear, along with the allowable load for the corresponding nominal diameter; adjustments are also made based on factors such as diameter, temperature, and operating conditions. I. Core basis: Total load vs allowable load (NB/T 47065.1). To calculate the actual total load, consider the container’s own weight (vessel body + head + accessories), the weight of the medium (volume × filling factor × density), as well as additional loads such as insulation, ladder platforms, and those caused by wind, snow, earthquakes, etc. Refer to the standard allowable loads. For the same DN, the allowable load for the heavy-duty Type B is much higher than that for the light-duty Type A (due to thicker walls, ribs, and bottom plates). Process: Calculate the total load → Check the allowable loads for Type A/B at the same DN → If the load is within the allowable limit of Type A, choose Type A; otherwise, choose Type B.

II. Key influencing factors (directly determine the load and selection): Nominal diameter DN. For DN ≤ 900 mm, only heavy-duty types are available, as there are no light-duty types (small sizes with little structural difference). For DN > 900 mm, both Type A and Type B are available, and the choice depends on the load. Container length and filling level: Longer containers, higher filling rates, and high-density media (such as water or liquids) result in higher loads, thus a preference for heavy-duty types. Shorter containers, lower filling levels, and low-density media (such as gases) result in lower loads, thus a preference for light-duty types. Operating conditions: High temperatures or large temperature differences lead to greater thermal expansion and higher stress, so heavy-duty types with sliding saddles (Type S) are preferred. Under normal temperature and pressure conditions, displacement is small and stress is low, so light-duty types with fixed saddles (Type F) can be used. For heat exchangers or containers with internal components, the heavy weight of these components and high vibration levels mean that heavy-duty types are usually the better choice.

III. Essential differences between Type A and Type B (in terms of load-bearing capacity): Light-duty Type A features thin walls, fewer ribs, and a narrower bottom plate, resulting in a lower allowable load. It is suitable for medium-sized containers with light loads operating at normal temperatures. Heavy-duty Type B has thicker walls, more ribs, and a wider bottom plate, allowing for a higher allowable load. It is suitable for large containers with heavy loads, as well as those operating at high temperatures or used in heat exchangers.

IV. Selection guideline: First, calculate the total load, then consider the DN value ； Small DN: full heavy duty; large DN: specific load ； Choose Type A for light loads; Type B is mandatory for heavy loads, high temperatures, or heat exchangers.