Control valve & on off valve ,solenoid-valve manufacturer

Close this search box.

Professional Sight Glass Flow Indicator Manufacturer

●Small in size.

●Easy and rapid operation

●Good sealing characteristics.

●Good flow regulation function.

●Easy maintenance.

●A wide variety of unique materials to meet the most diverse applications.

●Practical methods of flow monitoring.

Get in Touch with Us

    A Reliable Sight Glass Flow Indicator Supplier In China

    The BCST flow indicator is a device used to observe the condition of materials inside the vessel. The sight glass flow indicator gauges the direction, speed, and flow of the process material. It is a product installed in a tube that provides a visual aid to verify movement and accuracy of liquid flow. Unique mechanisms can be mounted in most sight glass flow indicator models to enhance visibility when observing a liquid.

    BCST flow indicators never go out of style, but require occasional replacement, as part of the overall facility maintenance plan or to repair damaged units. When installed in process piping, visual flow indicators allow visual observation of flow direction and rate liquids, dusts or gases, as well as the color and sharpness of the material, through one or more observation windows. BCST sight glass flow indicator is divided into valve sight glasses, pipe sight glasses, straight through sight glasses, and industrial sight glasses.

    BCST - A Top Rated Sight Glass Flow Indicator Suppliers In China

    BCST sight glass flow indicators are used to observe the flow of process fluids, including process liquids, pharmaceutical processing, chemical processing, biofuels, liquid food products, petroleum processing, steam lines, powdered food products and food processing, etc. Through the window of the glass flow indicator, an operator can observe the flow direction, the approximate flow rate and flow characteristics of the process fluid, without interrupting the process flow.

    Double window sight glass flow indicator

    Double Window Sight Glass Flow Indicator

    flow indicator

    Wheel Sight Glass Flow Indicator

    Paddle Wheel Sight glass Flow Indicator

    Paddle Wheel Sight Glass Flow Indicator

    sanitary sight glass flow indicator

    Sanitary Sight Glass Flow Indicator

    Thread Sight glass flow indicator

    Thread Sight Glass Flow iIndicator

    tubular sight glass flow indicator

    Tubular Sight Glass Flow Indicator

    BCST Supply One Stop Sight Glass Flow Indicator Solution for Your Project

    Established in 2000 and is a popular organization in the manufacturing industry, BCST export a variety of sight glass flow indicators, etc. From low-cost cast models that are easy to install to high-end units that can withstand high temperatures and high pressures, we have a wide range of products to choose from. We pride ourselves on developing high-quality products that are valued for their long service lives, high strength, and perfect finishes.

    We can provide the tools you need to revolutionize your business processes and get more done. Contact us, and let’s work together. Reach out to one of our experienced engineering teams today, and we’ll find custom-tailored solutions that meet your needs. Feel free to let us know about any special requirements your business has, and we’ll work on creating custom solutions for you. BCST is the premier bellows sealed stop valve manufacturer. 

    Please E-mail us at [email protected] or go to

    Get the Latest Catalogue Now!

    Sight Glass Flow Indicator Application

    Sight Glass Flow Indicator -FAQ

    What Exactly Is A Sight Flow Indicator?

    A sight flow indicator provides a powerful window into a process pipeline, giving operators an easy and cost-effective way to check liquid flow and verify its direction. Moreover, it allows operators to observe the color, clarity, consistency, viscosity, and other characteristics of process fluids, giving them a complete understanding of the process.  


    A sight flow indicator is a device used to monitor the flow of liquids and gases in a pipeline. It typically consists of a glass column or two opposing windows mounted to the channel, with a body or head made of a specific metal. The windows are usually made from special glass discs in a gasket assembly, fused in a metal frame, or made from tubular glass. In some cases, polymer windows are used. This device provides a visual indication of the flow rate, allowing for quick and easy monitoring of the fluid flow.


    Two main types of sight flow indicators are available to view the flow of a liquid or gas. The first type has two opposing windows, one for viewing the flow and the other to allow light to illuminate the flow. The second type is a glass tube design which allows for 360-degree viewing of the flow. Both types of sight flow indicators offer a practical and accurate way to monitor the flow of a particular liquid or gas.


    Often, sight flow indicators are fitted with components that make the flow of process fluids visible to the operator. These components, which move in response to the flow, make it easy to quickly identify the direction of the flow and any changes in the properties of the process fluid.


    Sight flow indicators visually indicate liquid levels and flow in pipelines. Easily attachable to fittings via flanged, threaded, weld-type, or sanitary clamp connections, the indicators are available to fit standard pipe sizes ranging from ¼-inch to 12-inches, with some carrying ANSI pressure & temperature ratings.


    Sight flow indicators may appear out of place in our highly automated and networked plants, but there are times when visual inspection is the only option. Flow measurement and control are essential to the successful operation of any plant, and there is no better way to gauge what is happening inside a pipeline than to see it.  With a sight flow indicator, operators can easily monitor the process fluid and ensure it moves correctly and at the correct rate.


    As a simple and cost-effective way to ensure reliable readings, a sight flow indicator offers reliable, low-cost redundancy. A sight flow indicator is a fail-safe device that cannot give a false reading, lose power, or fail to read, making it an ideal choice for reliable monitoring.




    What is Applications for Sight Flow Indicators

    Sight flow indicators are essential components of process control in many industries. They help operators visualize the flow of process media, from liquids, and gases, to powders, enabling them to monitor pipelines for scale build-up, residue, and foreign matter, especially during cleaning routines.  With their easy installation and reliable operation, sight flow indicators are used in a variety of applications, including:

    • Liquid:process liquids, suspended drugs, pharmaceutical reactions, chemicals, biofuels, liquid foodstuffs, and petroleum products.
    • Gas:include steam, nitrogen used in food packaging, gases used in chemical and semiconductor processing, and petroleum gases.
    • Powder:Plastic resins, powdered foods, inorganic powders, and bulk dry chemicals are all examples of powder. Sight flow indicators are used by operators to confirm the free flow of materials and to view the blending of materials.

    Through the window of the sight flow indicator, an operator can observe the flow direction, the approximate flow rate, and the fluid characteristics of the process without interrupting the flow. There are many applications.

    • Steam Pipelines

    Steam pipelines are essential for many industrial processes, as they provide an economical way to transfer heat. However, due to mineral residue and rust, steam pipelines can become cluttered and difficult to maintain. A sight flow indicator is an effective and reliable tool for identifying and addressing these issues. Furthermore, condensate can also be placed through a sight flow indicator, allowing for quick and easy maintenance. Steam-heated jackets can be employed to keep the device at the ideal process temperature for applications in which the sight flow indicator may cause an unwelcome excellent spot in the processing pipeline.

    • Chemical Processing

    Chemical processing is essential for production in many industries, and pipelines are used to move liquids and gases through filters, cooling lines, pumping lines, and transfer lines.  Sight flow indicators are vital for monitoring and maintaining these pipelines; they allow operators to detect and identify problems like clogs, solids, and foam and verify instrument readings.  By using sight flow indicators, operators can quickly locate the source of a decrease in flow or determine if maintenance is required.

    • Pharmaceutical Processing

    Pharmaceutical processing requires precise monitoring of processes to ensure the safety and efficacy of drugs. Sight flow indicators are essential for process operators to monitor fermentation processes, such as the presence of color or foam. For these applications, the indicators must be designed for sterile service, crevice-free, and tolerant of clean-in-place and sterilize-in-place procedures. With sight flow indicators, operators can quickly and safely confirm that cleaning has taken place and no residual cleaning solution remains – an essential step to fulfill FDA standards.

    • Food Processing

    Sight flow indicators are essential for food processing applications, such as in breweries, for monitoring beer and trub as it passes through the brewing process. Glass indicators provide an ideal solution for operators to monitor color and other characteristics necessary for quality inspection easily. Beyond beer, sight flow indicators are commonly used in applications involving the conveyance of dry bulk powders like flours, dehydrated food powders, and food additives.  Plastic sight flow indicators can be fitted with a flow indication component to ensure the proper flow of transparent gases, like nitrogen, used in food packaging.

    • Lubrication  

    In discrete manufacturing, proper lubrication is essential for smooth operation and optimal performance of machines. Sight flow indicators are used to monitor oil levels and check for color, which may indicate that the oil needs to be changed or replaced. Regular maintenance and proper lubrication ensure your machines are in peak condition and running efficiently.

    • Petroleum Processing

    Sight flow indicators allow petroleum plant operators to quickly and easily identify and confirm the flow of petroleum and other process media while inspecting it for any unwanted particulates.  In sulfur processing, for example, using a sight flow indicator can help ensure that the sulfur is flowing smoothly and at the correct temperature. This helps to avoid disruptions caused by temperature fluctuations, allowing operators to maintain a safe and efficient production process.

    Sight Glass Types: What Are They?

    Sight glasses are essential for monitoring oil levels and spotting potential contaminants in reservoirs and machines. With two primary forms available – bullseye and columnar – sight glasses provide an efficient and effective alternative to using a dipstick or opening a tank to inspect the oil visually. Not only does this help prevent air, moisture, and other contaminants from entering a closed system, but it also helps keep your system running optimally and efficiently.


    When installing sight glasses, it’s essential to consider the risks involved. For example, columnar sight glasses are often mounted outside tanks, leaving them vulnerable to potential damage. On the other hand, bullseye sight glasses offer an alternative but require precise placement to provide accurate readings. Therefore, it’s essential to carefully evaluate each option before making a final decision.

    In this post, you’ll discover the different types of sight glass and why using one is essential. Then, we’ll discuss the benefits of using a sight glass, how to identify them, and the various types available. We’ll also provide tips for selecting the right sight glass for your application. Finally, we’ll explain why using sight glass is essential and why it’s a good choice for many different industries. By the end of this post, you’ll better understand the importance of sight glass and how it can help improve the safety and productivity of your operations.

    What is Sight Glass Types

    In general, sight glasses can be classified as bullseye or columnar, but you should consider a few key differences when selecting the best one for your operations. Bullseye sight glasses provide a clear view of the liquid level within the vessel but can be more prone to breakage and dirt buildup. Columnar sight glasses are more durable and provide a more accurate reading of the liquid level within the vessel, but they may be more challenging to see through. Whichever you choose, consider the equipment’s function and your specific application needs before making a decision.



    A bullseye sight glass is an invaluable tool for monitoring tank oil levels. To install a bullseye sight glass, drill a hole at the top of the optimum oil level and thread a bolt with a glass head into the hole. Some models also have a line in the glass, allowing operators to identify the correct oil level when the equipment dashes. The key benefit of using a bullseye sight glass is detecting foaming in the system, usually caused by water and other contaminants. Early detection of foaming is essential for avoiding costly repairs and damages.


    Columnar sight glasses are a great way to view the oil inside your tanks better. They provide a clear, vertical tube outside the tank that allows you to see a larger sample than traditional bullseye sight glasses. However, columnar sight glasses can be more challenging to install and are typically mounted near the bottom of tanks, making them more susceptible to damage. Additionally, they draw from the bottom of tanks, so they don’t usually display problems related to foaming oil. One significant benefit of having columnar sight glasses over bullseye is the ability to mark oil levels while a machine is running and idling. It is only possible to see one of these images when you are wearing bullseye sight glasses, but columnar sight glasses allow you to see both. This is invaluable for ensuring that your machines are running safely and efficiently.

    BS&W Bowls

    Bottom sediment and water (BS&W) bowls are essential to tank systems and are mounted to the bottom of tanks to help protect against damaging metallic contaminants. Many BS&W bowls feature a powerful magnet that attracts metallic particles and a release valve that can be used to collect oil analyses. The advantage of mounting them to the bottom of tanks is that they remain relatively small and protected, unlike columnar options, which can be easily damaged.


    This bullseye sight glass is designed to extend outward from a tank, so you can view the oil from multiple angles, making it easier to spot contaminants. Constructed from durable materials such as glass, acrylic, or polyamide, this sight glass is built for extreme pressures and temperatures. Plus, its unique design allows light to pass through the oil, making it easier to identify contaminants. As a result, this bullseye sight glass gives you a better view of your oil and its contents.



    Discover the power of multifunctional devices with features that combine the best options in one package. Get the added benefit of sight glass removal for cleaning and inspection to maintain your device and keep it running optimally. Make your life easier with these multifunctional devices, and enjoy the convenience of not switching between products.


    Why You Should Use a Sight Glass?

    The life of an oil system can be significantly extended if you take the time to do a simple visual inspection. With a sight glass, you can quickly identify potential problems without opening a closed system, which means no contaminants like moisture or debris can get in during an inspection. Taking the time to inspect your oil system regularly will help ensure its peak performance and longevity.

    It’s essential to look beyond the color of the oil when considering the number of contaminants present, their size, and the potential wear of engine components. A sight glass can provide valuable insight, but adding a magnetic option can be even more helpful. This magnet draws any metal fragments to it, allowing you to quickly identify whether the wear you see is normal or needs to be addressed. With this additional tool, you can better identify potential contaminants and engine wear issues before they become a problem.

    Monitoring oil levels in your equipment is essential for keeping it running smoothly. With a sight glass, you can quickly and easily determine the proper oil levels in tanks and machines with a single glance. Keeping an eye on oil levels is an easy and effective way to ensure the best performance from your equipment.

    BCST Sight Glass

    BCST is one of the leading reliable and stable sight glass manufacturers in China. Our sight glass solutions are designed to offer wide material selection, ease of maintenance, high pressure and temperature availability, and explosion-proof and anti-corrosive structure. With our strong technical background, professional team, and budget-friendly products, BCST is your most suitable choice for your next project. Our sight glass is set up right into a pipe to offer a visible view verifying liquid flow for route and accuracy of flow rate, and also provide visual observation of the direction and rate of liquid flow, powder, via one or more observation windows. With our wide selection of flanged, threaded, or sanitary clamp connections, you can trust BCST to provide you with the best sight glass solution for your needs.


    Get in Touch with Us