How to seal a glass reactor?

Glass reactors are a common laboratory device, characterized by high transparency, high temperature resistance (-20℃ to 200℃ for standard models), corrosion resistance (compatible with most acids, alkalis, and organic solvents), and no pollution to materials. As a trusted supplier of laboratory equipment, Nanbei Instruments offers high-quality jacketed glass reactors, single-layer glass reactors, and customized models – widely used in various experimental and production processes such as chemical synthesis, pharmaceutical R&D, and material testing.

Sealing is a critical part of glass reactor operation, directly affecting reaction safety, efficiency, and environmental protection. Poor sealing may lead to material leakage, gas emission, or air ingress, which can destroy the reaction system or cause safety hazards. There are two main sealing methods for lab glass reactors, each with distinct characteristics and application scenarios:

1. Packing Seal (Compression Packing Seal):

The packing seal is a traditional and cost-effective sealing method, composed of flexible packing materials (such as PTFE, graphite, or asbestos-free fiber) and clamping components. The operation principle is: rotate the evenly distributed clamping bolts on the reactor cover, press the cover against the packing material, make the packing deform radially, and form a tight contact with the rotating shaft surface to block the leakage channel.

Key Notes for Use:

• Select packing materials according to the reaction medium (e.g., PTFE packing for strong corrosive materials, graphite packing for high-temperature reactions).

• Control the clamping force moderately: over-tightening will increase shaft wear and power consumption; over-loosening will cause leakage.

• In chemical production or high-pressure reactions, shaft seals are prone to leakage. Gas spillage can pollute the environment and even cause fire or explosion accidents; therefore, the working pressure must be strictly controlled (generally not exceeding 0.1MPa for packing-sealed glass reactors).

• Regularly inspect and replace packing materials to maintain sealing performance – Nanbei Instruments provides matching packing accessories for its glass reactor product line.

1. Mechanical Seal:

The mechanical seal (also known as end face seal) is a high-efficiency sealing method, consisting of four core parts: a rotating ring (matching the shaft rotation), a stationary ring (fixed on the reactor cover), a spring loading device (providing preload), and an auxiliary sealing ring (O-ring or V-ring for secondary sealing). Its working principle is: due to the elastic force of the spring and the pressure of the medium, the rotating ring and stationary ring are tightly pressed against each other to form a sealed end face. When the shaft rotates, the rotating ring rotates with the shaft, while the stationary ring remains stationary. The annular sealing end face (with high flatness and smoothness) blocks material leakage, and the auxiliary sealing ring prevents leakage from the fit surfaces of the rotating ring and shaft, stationary ring and cover.

Key Advantages & Applications:

• Although the mechanical seal structure is somewhat complex, its sealing effect is excellent – almost zero leakage, suitable for high-pressure (up to 0.3MPa), high-vacuum, or volatile medium reactions.

• It has low friction coefficient, small shaft wear, and long service life, reducing maintenance frequency.

• Recommended for scenarios requiring strict sealing, such as vacuum distillation, toxic material reactions, or high-purity product synthesis. Nanbei Instruments' premium glass reactors are equipped with imported mechanical seals for enhanced reliability.

Selection Guide for Sealing Methods

Wide Applications of Jacketed Glass Reactors

Jacketed glass reactors (a hot-selling product of Nanbei Instruments) are widely used in: high-temperature reactions (heated by oil bath or electric heating), low-temperature reactions (cooled by ice bath or refrigerated circulating pump), vacuum reactions (such as molecular distillation), distillation and reflux reactions, purification reactions, concentration reactions, and stirring reactions. They are essential equipment in research institutions, university laboratories, and industrial production (chemical, pharmaceutical, food, cosmetic, and material industries).

To ensure optimal sealing performance, it is recommended to use original accessories and follow the operation manual. For more details on Nanbei Instruments' glass reactors, including technical parameters, customization services, and after-sales support, please visit our product page. For matching equipment such as laboratory refrigerated circulators or vacuum pumps for glass reactors, feel free to contact our sales team.