Mastering Vial Crimping: The Essential Guide for Analytical Labs

What is vial crimping?

Jun. 28th, 2024
There are three types of vial caps for sample vials: crimp caps, snap caps, and screw caps. Each type of closure has its own advantages. This article will introduce you to crimp caps, one of the three types of closures. You can learn the benefits of choosing crimp caps. You can learn the precautions and how to use tools for sealing. You can also learn about types of crimping machines.

Crimp caps vs crimp vials

Crimp caps

Why should we've chosen crimp cap sample vials? The sample vial cap can ensure the tightest seal and reduce the chance of sample evaporation.
Crimp caps are usually made of aluminum or stainless steel with a PTFE/silicone septum. Metal is best for special uses. These include resisting high heat and pressure.
Crimp caps squeeze the septum between the rim of the glass sample vial and the folded aluminum cap. The seal excels and prevents sample evaporation with complete success. The septum remains in place. The needle of the autosampler pierces the sample. The crimping machine must seal the crimp cap sample vials. For a small number of samples, a manual crimping machine is the best choice. You can use an automatic crimping tool for a large number of samples.

Crimp vials

Vials requiring crimped seals play a crucial role in chromatography testing. Manufacturers make common crimp vials using glass and plastic. Glass crimp vials are clear. This allows for a clear view of the sample and a swift assessment. At the same time, crimp vials have excellent seals and anti-pollution properties. They can cut sample loss and protect precious samples.

Want to know why crimp vials are used in chromatography? Click this article to learn: Why are Crimp Caps Used in Chromatography? 6 Reasons

Types of Crimping Tools

Crimp vials have many advantages. Yet, during testing, experimenters face many samples. This means we need to cap many vials. How do we confine them with minimal risk, simplicity, and speed?
Use a precise crimping tool to form a secure vial seal. It's crucial to choose a suitable crimper. Crimpers on the market fall into two categories: manual and electric.

Manual crimper

The manual crimper tops the list of types in frequent use. The user needs to apply pressure. The tool includes a handle, a crimping head, and an adjustable device, all made of stainless steel. The knob adjusts the capping force. It can be set as needed. This allows it to fit different types and sizes of sample vials.
The length is about 20-30cm. It's like a "big pair of pliers" with a round capping head on top. It's suitable for 8mm, 11mm, 13mm, 20mm, 30mm, 32mm, and other specifications of jaw caps.

Electric capper

The electric capper is an emerging capping device. Compared with manual capping operations, the electric capper and decapper reduce hand fatigue. It has a rechargeable lithium-ion battery. You can use it with one hand. You can cap the sample bottle with one click, over and over. The user only needs to place the sample bottle on the tray. They can then cap it without removing it. 
The manual capper is a more affordable tool for experiments. It is still popular in many small and medium-sized labs. The mechanical mechanism is also more stable and rarely damaged or unusable. But, for experiments that need to process many samples or need high consistency and precision, the electric capper may be better.

If you want to know everything about the capping machine, you can learn from this article: All About Vial Crimpers: A Detailed 13mm & 20mm Guide

How the crimping process works. 


How the manual crimper works.

The manual crimper relies on the lever principle. It uses a mechanical compression mechanism to seal the sample bottle.
First, adjust the positioning screw. First, loosen the locking nut. Then, set the screw's height based on the required tightness. If the crimping is too loose, lower the screw. If it's too tight, raise the screw. Finally, tighten the locking nut at the bottom.
Second, if the crimper can't be adjusted well using the positioning screw alone, you need to use an Allen wrench. Use it to adjust the screw in the middle of the crimper. If it is too loose, turn the Allen wrench counterclockwise, and if it is too tight, turn it clockwise.

How the electric crimper works.

The electric crimper's working principle is more complex and automated. It is more so than that of the manual crimper. It mainly uses a motor and a control system to realize the automated crimping of the sample bottle. The electric crimper is equipped with an electric motor, which drives the crimping head to apply pressure. The rotational force of the motor is converted into a vertical crimping movement through a transmission device.