A laboratory press is a device used to apply pressure to a sample, in order to compress or compact it. Laboratory presses are often employed to study the properties of materials, or to prepare samples for further analysis.
Laboratory presses are typically equipped with a hydraulic system that can generate up to 1,000 pounds per square inch (psi) of pressure. The press can be used to apply pressure to a variety of materials, including powders, sheet materials, and polymer beads.
A hydraulic press uses an oil-filled hydraulic cylinder to generate a compressive force on a moveable piston. The machine works using the principle of Pascal’s law, which states that the pressure exerted on a fluid is transmitted evenly throughout that fluid. The force generated by the press is proportional to the area of the piston, multiplied by the applied pressure. The press consists of a cylinder with a piston inside, and a pump that is used to apply pressure to the oil inside the cylinder.
How a hydraulic press works
Laboratory presses are available in a variety of sizes and configurations, including manual or automated operation. Choosing the right hydraulic press for your lab will, unsurprisingly, come down to its intended application – as well as how much time and energy your technicians will expend on using it.
A laboratory press is frequently used in conjunction with a pellet die for compacting powders into solid disks. Other tools and moulds can be used for pressing, bending, or forming thin films.
A manual hydraulic press uses a hand-operated lever to pump the oil and apply load to a sample. A hand-operated valve is used to relieve the pressure and remove the load.
The manual presses manufactured by Specac are available in 15 and 25-tonne maximum load configurations and are ideal for FTIR, KBr and XRF sample preparation.
There are no electronic components in a manual hydraulic press and, as a result, this machine is often cheaper than its automatic counterparts; however, choosing a manual press shouldn’t just come down to the purchase price.
When you consider if a manual hydraulic press will suit your laboratory operations, it’s best to review your workflow. Manual presses require more physical effort to operate than an automatic equivalent – so if your technicians will need to use them often, it can become labour-intensive work.
A manually operated press is also harder to use in a repeatable fashion, with every sample being pressurised to a slightly different load by the operator.
However, for infrequent use, a manual press can be a cost-effective addition to your laboratory set-up.
An automatic hydraulic press uses an electric motor to drive the pump and electric switches to open and close the relief valve. This means they can be controlled to a high accuracy and repeatability.
Automatic hydraulic presses are often used for industrial XRF applications and other laboratory sample manipulation activities. However, their versatility makes them suitable for small and large-scale manufacturing practices, too – including hot embossing, laminating and melting polymers for thin films.
Unlike the lever on a manual hydraulic press, an automatic press is operated by a button. The general mechanics of the two machines are similar – you set the load you want to be applied, which the pump then fulfils – but the die used in an automatic machine can often press and release via automated actions.
Automatic hydraulic presses often improve the workflow in busy laboratories, as – once the press is programmed – it can operate autonomously, allowing the technician to get to work on other tasks.
Available in 8, 15, 25 and 40 tonne configurations, automated presses aren’t as laborious to operate as a manual counterpart. This makes them suitable for frequent pressing work – as well as often being more accurate and consistent, due to the lack of variable factors during use.
Where laboratories are running XRF measurements on a large quantity of samples, it makes sense to have a high-throughput hydraulic press for XRF, specifically adapted to the demands of preparing sample pellets. These presses feature integrated pellet dies and have swifter operations for repeated use. In particular, they focus on automations and mechanical systems for quickly extracting the pellet and leaving the press available for the next sample.
A hydraulic mini press is a small, portable press that uses hydraulic power to produce force. They typically only weigh 4 kilos but are still capable of applying around 2 tons of pressure.
Mini presses are typically used to produce KBr discs for FTIR. As the surface area of these pellets are about 7mm – smaller than the usual 13mm diameter of a regular pellet – this enables an equivalent pressure to be applied, despite the lower tonnage.
Mini presses are often favoured due to their compact size. They’re hand-held, easy to transport and low-cost, making them an accessible choice for pharmaceutical labs, polymer testing labs, undergraduate chemistry labs and many other places where FTIR is commonplace.
Specac offer a comprehensive range of sample preparation accessories for FTIR, including presses, pellet dies, high temperature film makers, and consumables such as KBr powder.
Besides these, a variety of other sampling techniques – including single and multiple reflection ATR, DRIFTS, and Specular Reflectance – are available.
Our accessories are customised and calibrated for the user’s needs, so why not contact our experts for a quote?