What is the difference between Blind Flange and Spectacle Blind Flange?

1. Different appearance

We can easily distinguish between blind flange and spectacle blind flange by their appearance. Blind flange is a flange without a hole in the middle. The spectacle blind flange is composed of two round steel plates, one solid and the other hollow, connected by flat steel. Due to its resemblance to the shape of an '8', it is also known as figure 8 blind flange.

2. Different functions

Blind flange, due to its solid structure in the middle and good sealing performance, is generally used as a reliable means of isolation and cutting for systems that require complete isolation. It plays the same role as the head and pipe cap. However, blind flange is fixed by bolts, while the head and pipe cap are generally fixed by welding and cannot be disassembled at any time. Therefore, blind flange is more flexible, convenient for disassembly, and plays a role in removing impurities from the pipeline during maintenance.

The figure 8 blind flange is also a commonly used accessory in pipelines. Due to its external characteristics, the spectacle blind flange can flexibly switch positions, thereby closing or opening the pipeline and controlling fluid flow. It has the same function as blind flange, such as convenient maintenance. When it is commonly used in pipelines that need to change the direction of the fluid, it is usually used on pipelines with larger diameters. Usually, a circular end is used to occupy the spacing to keep the pipeline unobstructed, and a blind plate of the same thickness on the other end can cut off the pipeline.

3. Different characteristics

Blind flanges are mainly used to completely isolate the production medium and prevent production from being affected or even causing accidents due to inadequate closure of the shut-off valve. Blind flanges should be installed in areas that require isolation, such as at the equipment connection port, before and after the shut-off valve, or between two flanges.

The spectacle blind flange is easy to use. When isolation is required, the blind end is used. When normal operation is required, the ring end is used. It can also be used to fill the installation gap of blind flanges on pipelines. Another characteristic is that the identification is clear and easy to identify the installation status.

What are the similarities between blind flange and spectacle blind flange?

1. Material selection: The materials mainly include carbon steel, stainless steel, and alloy, which can be selected according to the pressure level and medium of the pipeline

2. The useage in pipelines, vessels, and other equipment in the chemical industry can effectively isolate, regulate medium flow, or protect equipment safety.

3. Oil and gas industry: It can be used for pipeline maintenance, cleaning, inspection, and oil leakage prevention in the oil and gas industry.

4. Food industry: It can be used to control flow or isolate, clean, and detect environmental media in food production.