Oval manways

Stainless steel oval manways – basic information

Oval manways are used as an inspection component, usually mounted in the side wall of a stainless steel tank. Thus, among oval manways there is a wide range of models with increased pressure resistance.

Stainless steel oval manways (next to round manways) are one of the most common equipment of stainless steel tanks used for various purposes, especially pressure tanks.

Types and parameters of oval manways for tanks

The most important selection parameters among the oval manways group are:

manway dimensions (width and height),
opening direction (inward/outward),
pressure resistance,
construction type (straight or bent to the diameter of the tank),
construction material (AISI 304/304L or AISI 316/316L).

Stainless steel oval manways – dimensions

Due to its specific design and application, within the oval manway category, the dimensional variation between individual models is not significant. Thus, oval manways usually have a longer side of 400-500 mm (common dimensions: 440x308 mm, 440x340 mm, 400x490 mm).

However, we also offer models with larger dimensions, where the longer side of the manway exceeds 500 mm (for example: 550x450 mm, 540x410 mm) or even 800 mm (600x800 mm).

2 ways to open oval manways

The way a manway opens defines to a large extent its pressure resistance. Due to this parameter, a distinction is made:

manways that open inward,
manways that open outward.

The former group (inward opening manways) is dominant among oval manways. This is primarily due to the practicality and versatility of this solution.

Inward opening oval manways use the inner frame surface as a pressure zone, which is permanently bonded to the tank shell. Thus, the value of the pressure that acts on the manway may be higher than for manways that open outward. Oval inward opening manways are therefore often used in large diameter and large capacity tanks, as well as in specialised tanks (for example, CCT or BBT tanks used in beer production). On some models in this group, there is a possibility to remove the manway to the outside of the tank.

Outward opening oval manways are used in tanks whose small diameter does not allow for free installation and use of the inward opening manway. Furthermore, the maximum pressure resistance of such a manway is much lower and usually does not exceed 0.5 bar. However, these types of manways can also be used as top lids, for example as an alternative to round manways.

Pressure resistance of oval manways

Due to its design and purpose, the oval manway category is also characterised by increased pressure resistance. The vast majority of standard oval manways have a pressure resistance between 2 – 4 bar. However, specialized PED-certified models are also available with pressure resistance as high as 10 bar.

Oval manways bent to the tank diameter

A characteristic feature of oval manways is the fact that some of them can be manufactured only for special order – these are oval manways bent to the diameter of the tank.

In case of bent manways, the selected model is manufactured according to the declared diameter/radius parameter of the tank, in which the manway is to be installed by default. An extremely practical aspect of this type of solution is the possibility to obtain a highly aesthetic design, in which the frame of the inspection opening (manway) does not protrude beyond the outline of the tank shell.

For oval manways, a special cover with a door is provided as an accessory that allows thermal insulation of the main manway opening. This is particularly desirable when using oval manways in thermally insulated tanks.

Parameters