4 Jan 2018

How Does a Hydraulic Press Work? | Animated Guides

A hydraulic press is a compression device that makes use of an exerted force placed upon a fluid, to create a resulting force according to Pascal's Law. It was actually invented by Joseph Bramah, so is also known as the Bramah Press.

How Does a Hydraulic Press Work?

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What is Pascal's Law? The Hydraulic Principle explained

Pascal's Law is a theory which states that the pressure (P) in a confined fluid, caused by a force (F1), over an area (A1), is transmitted undiminished, causing a force (F2), over the area (A2). This law can be applied to magnify a small force by the ratio of the areas to give a larger force – F2 = F1 (A2/A1).

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How does a hydraulic press work? Pascal's Law in action

In a hydraulic press, a modest mechanical force (F1) is applied to a small area (A1). As the fluid is moved in one location, it inevitably moves elsewhere within that channel. Then a larger area (A2) generates a magnified mechanical force (F2). The force is transmitted via hydraulic pressure generated by the initial effort, F1. 

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Application areas are almost limitless. Usually, a laboratory hydraulic press will be used to prepare samples for analysis by compressing them into pellets or thin films. The particles are forced together, creating a homogenous sample ideal for spectroscopic examination.

The Specac Manual Hydraulic Press is a classic example of the Bramah Press. The user applies pressure by hand, using a handle to pump pressure into the hydraulic fluid system. This pressure is transferred to a secondary area and the resulting force can be as great as 25 tons.

A manual hydraulic press, a classic example of the Bramah Press, follows Pascal's Principle to compress samples for spectroscopic analysis.


FTIR spectroscopy is an analytical technique for the determination of a samples molecular structure that utilizes this method  of sample preparation via compression from a hydraulic Press. KBr (potassium bromide) is often mixed with ground samples and compressed into pellets, which are then used for Infrared spectroscopic analysis. Suitable powder mixtures can also be compressed to form pellets in a similar way for determination of their compositional makeup using XRF spectroscopic analysis.

Milled or finely ground, powdered samples are placed inside a 'pellet die'. This is a durable container for the sample in which a die with sample is placed within the press. As the die is compressed within the hydraulic press, an internal plunger for the die assembly is forced against the contained sample within.

Other applications for hydraulic presses include pulling samples apart for tension testing, Sun Chemical have been using the same Manual Hydraulic Press of ours for over 30 years, doing just this.

Different types of hydraulic presses

At Specac we provide two types of powered (electric) hydraulic presses and two types of manual hydraulic presses. The manual presses available can be either full size or handheld. The electric presses come either with or without LED touchscreens and custom programmable loads.

Mini-Pellet Press

The Mini-Pellet Press is a handheld, manual hydraulic press, which is ideal for pressing 7 mm KBr pellets for infrared spectroscopy. It is rugged and durable, like the larger manual press, but lighter and portable. It operates at two tons of load.

How does a hydraulic press work? The Mini-Pellet Press is a handheld manual hydraulic press. It is portable and durable.

Manual Hydraulic Press

The Manual Hydraulic Press is a popular laboratory and industrial press as it is cost efficient, reliable, consistent and powerful. It operates at 15 or 25 tons of load, but can be converted to lower loads.

Power Automatic Hydraulic Press

The Power Press is a rugged automatic hydraulic press,offering 8, 15 and 25 ton options with a low noise operation and microprocessor-controlled load and release.

An automatic hydraulic press which works using Pascal's Law.

Autotouch Automatic Hydraulic Press

The Autotouch Automatic Press is very similar to the Power Press, but more advanced. It has an LED touchscreen which can be used to program complex loads. It comes in 8, 15, 25 or 40 ton options.

We hope you have learnt something new about the hydraulic press!

To summarize our laboratory hydraulic press offering:

  • The Mini-Press is a handheld, lightweight device providing up to 2 tons of pressure, ideal for KBr pellet pressing.
  • The Manual Hydraulic Press is a classic Bramah Press, perfect for pressing XRF pellets, KBr pellets or other kind of pellets. It's also used for film-making.
  • The Power Hydraulic Press is a rugged, electronic powered hydraulic press with pressures up to 25 tons.
  • The Autotouch Hydraulic Press is a cutting-edge industry-leading electronic press, with tonnages up to 40 tons, a multi-lingual LED screen and the option to program and store press cycles.

To learn more about what spectroscopy can do, check out #SpectroscopySolutions for more insights into the applications XRF and FTIR can fit.

Look up #SpectroscopyGuides for tips and tricks to help your analysis.

Also, check out our #SpectroscopySolutions presence on YouTube!