How to Handle Glass-Lined Vessel Problems

As mentioned above, common problems associated with glass-lined vessels are mechanical and thermal shocks. These defects severely damage the vessel, and unless these defects are removed, the vessel cannot get into production. Small, simple steps can be effective in preventing these problems.

· The operators should be properly educated. They should be trained for the importance of glass-lined vessels in pharma production, satisfactory working requirements, and harmful impacts of miss-handling.

· The glass-lined vessel should be operated according to standard specifications. The upper and lower limits of product temperature should not exceed the manufacturer's recommendations. Similarly, pressure requirements should also follow the manufacturer's recommendation. Following this specification will keep the vessel in healthy condition, resulting in the vessel's long life.

· Proper ground levels should be maintained and used. This keeps the vessel in stable condition and prevents any mechanical damage. 

Accessories for vessels

Glass-lined vessels are supplied with different types of accessories to facilitate vessel operation. These accessories of Glass lining equipment play a vital role in producing the product and are commonly used to monitor the whole production operation from start to finish. This is necessary to produce accurate results according to the required specification. 

Secondly, regulatory bodies also require the pharma manufacturers to record process parameters and keep the records. Regulatory bodies specifically inspect the process records during the inspection and can object if proper recordings are not made.

Some common accessories used in the glass-lined vessel include the following.

Temperature

Temperature is a common parameter that is monitored in a glass-line vessel. Pharma product manufacturing requires specific temperature requirements, as some chemicals require a specific temperature to react to form the desired product. Temperature is also monitored to regulate the internal temperature of the vessel. This is necessary to prevent the vessel from thermal shock. 

The temperature sensors should be removable from the port, so that calibration team can be easily perform the calibration. The length of the sensor, should be as deep as possible to accurately measure the solution temperature. The temperature sensor can be any type such as pt100. Both analog and digital type temperature sensors can be used.

Analogue type consists of a gauge with appropriately calibrated dials and readings, and can only be used for viewing. Digital types, shows temperature on LED, or LCD display. Digital types can also store temperature values for later recording.

Sampling Port

A sampling port is a vessel output port to take out a limited and calculated solution from the vessel. This is often required to take put sample to assess the manufacturing stage of the pharmaceutical product. A valve is also attached to the sampling port to control the solution flow, independent of the main valve. 

Earthing Port

Some solutions tend to generate static electricity when they contact the metallic surface. The static electricity remains in the system and can become hazardous for man and machine. It can cause electrical shock to humans and damage the machine's electrical system.

To prevent the hazards of static charge, the metallic surface is grounded. This transfers the static charge to the ground potential without causing any damage. Since glass-lined vessels' internal surfaces are coated with glass, these vessels require a particular port to connect to the vessel's metallic surface. This port is then used to ground the whole vessel.

How are glass lined vessel made

The manufacturing of Glass-lined vessels requires special techniques because it uses glass in its construction. The glass has a delicate structure, so if appropriate steps are not taken, the glass properties will be severe damage.

Similarly, the glass is bonded to the steel surface, and without unique characteristics of steel, bonding procedure will not occur, or the bonding will remain weak. The weak bonding will hinder the production process and damage the pharma product.

The manufacturing steps can vary from manufacturer to manufacturer, and it depends on the manufacturing technology, customer requirements, and product type.

Commonly, there are three main essential steps in manufacturing glass-lined vessels, as described below. 

Glass Production

The glass used to create glass lining is called enamel. Raw material comprising of oxides and silicates is used. The raw material is heated until it is melted. The melted form is cooled in water. The water decreases the temperature suddenly, and the molten state is converted into solid particles called Frit. In the final stage, the Frit is blended into powder form. Filtration is also used to remove any foreign body that could degrade the glass quality. The glass is now ready to be applied to the vessel steel surface.

Steel Production

The glass lining is created on the steel structure, requiring unique characteristics. The steel must have uniform thickness throughout its geometry to prevent different stresses. The steel must bear high temperatures associated with the glass-lining procedure without any deformations. The welding should also be performed without causing any defects to the steel.

The holes for different nozzles and ports should be created before applying glass material because nothing can be welded at the finished glass surface. Additionally, drive mounting and attachment for exterior accessories are made before the glass application.

The steel is Abrasive grit blasted at the final stage to prepare for the glassing procedure. An abrasive material is forcibly propelled against the steel surface under high pressure in this method. This method is applied at both interior and exterior of the steel vessel.

Glass-lining

The final stage is the application of glass on the steel surface. The glass is applied to the steel surface in two steps. The first step is called ground coating. The function of the ground coat is to develop a bond with the steel surface and facilitate glass attachment. This coat has limited resistance capacity and cannot be used for glass-lining.

After applying the ground coat, the vessel is allowed to dry. After drying, the vessel is transported to the heating chamber. The vessel is heated in a heating chamber for a specific time and temperature to bond the glass to the steel surface strongly. After heating, the vessel is cooled in a cooling chamber.

After the ground coat, subsequent coatings increase the chemical resistance and corrosion property. The final coating process is repeated until the desired glass thickness is achieved. The standard thickness for glass coating is 1.0 to 2.0 mm. 

Different performance tests such as spark and thickness tests are carried out during each coating process to maintain quality in the glass coating process.

After glassing completes, the vessel goes through a series of welding processes to weld different parts, such as a jacket. After welding, the vessel is painted in a paint booth.

After painting, the glass-lined vessel is ready for production and is shipped to the customer's premises.

Back to read: Market Overview of Glass Lined Vessel for Pharmaceutical Industry

About the Author:

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.