A Texture Analyser is an instrument used for measuring the texture or physical properties of materials, such as food, cosmetics, adhesives and pharmaceuticals. At their simplest, Texture Analysers are instruments that use a sequence of movements to compress, stretch or bend a sample. They typically operate by either applying a controlled force to a sample and measuring the resulting deformation or by deforming the sample in a controlled way and measuring the resulting forces.
During a basic test the Texture Analyser measures force, distance, and time data, at a chosen data collection rate and the data is presented as a curve on a graph, which when analysed indicates the texture of the sample. Users are able to adjust test settings, such as target forces or distances, test speeds and test modes (for example, tension, compression or cyclic loading). The instrument can also connect to various additional measurement devices (e.g. temperature, acoustic, video) for synchronised collection of data (via sophisticated software) during a compression/tension test.
Texture Analysers are used to measure textural properties of solid and semi-solid food samples. They provide quantitative data on sensory properties like crispness, stickiness, firmness, and stretchiness. They are essential in both product development and quality control and are available in a range based on instrument height and force capacity.
Key components of a Texture Analyser
Drive mechanism
The instrument consists of a vertical column (or 2 for the TA.HDplusC) or ‘frame’. A drive mechanism is a series of parts which moves the loading arm vertically. This is driven by a stepping motor which provides precise control over distance and speed using a fine ball screw and the use of gears and pulleys to ensure accurate and smooth movement of the arm. The choice and quality of parts used in this system determine the accuracy and precision of the arm’s movement.
Displacement is measured by counting pulses sent to the stepping motor. This ensures precise distance control and accurate measurement. The stepping motor moves one step every time a pulse is output from the microprocessor. On the TA.XTplusC and TA.HDplusC one thousand steps are required for each millimetre of arm movement. Therefore, the system has an internal resolution of 0.001mm. Resolution is 0.0005mm for the TA.XTplus100C model.
The arm and drive mechanism are coupled with reinforcement to provide further stiffness to the frame and encourage vertical movement, preventing side loading of the sample under test.
The bellows cover these mechanisms from the ingress of dust etc.
Instrument arm (Crosshead)
The arm is the main moving part of the instrument and is programmed to move up or down (or in a cyclic or sinusoidal motion) at a constant speed. It houses the load cell to which probes and fixtures are attached to deform samples during testing.
Should any of the standard library tests not provide you with your specific testing solution, the software is versatile to provide the user with the facility to write his/her own test sequence to move the arm in any movement combination you require with the ability to input time delays.
Load cell
The load cell is a force transducer that measures the force applied to the sample and is available in a wide range of capacities. It is sensitive and protected against overload conditions (with mechanical and/or electronic stops), ensuring precise and reliable measurements. The correct load cell is installed according the range of forces that need to be tested, similar to the idea of when you are choosing the correct weighing device based on range of weights you might wish to measure.
Calibration platform
This is where a chosen weight is positioned in order to check the accuracy of the load cell before testing.
Probe
A vast selection of attachments (probes or fixtures) can be connected to the load cell. The choice of attachment depends on the type of test you wish to perform or the property you wish to measure and whether the test is to be performed in compression or tension.
Test bed
This is where a sample is located for testing or where the lower part of a testing device is attached for support of sample between two parts. It is also where a heavy duty platform (for attachment of various fixtures) or additional devices (e.g. temperature control, powder flow measurement) are attached.
Test aperture
The test aperture is the maximum distance the arm can travel, critical for tests requiring large displacements. It is the distance between the underside of the arm at its maximum height and the instrument bed. Extended height models are available for specific applications requiring greater distances of tension or the testing of larger samples.
If the aperture is too small, certain tests may not be possible. For example, melted cheese extensibility testing and tensile testing of samples such as liquorice laces can result in large displacements. In some cases, a sample of lower initial length may be used to reduce overall extension. Alternatively, higher strain rates may be used to encourage earlier rupture in viscoelastic samples.
Instrument base
The base contains the electronics and drive components of the instrument. Timing is achieved by an accurate quartz crystal clock.
Electronics are a key component of a motorised Texture Analyser, determining the type and quality of data that is recorded. The electronics receive information from force, distance and time inputs (in some systems, time is inferred from distance), as well as (in some cases) auxiliary data streams including sound, video, temperature, resistivity, humidity or pressure. The various channels of synchronised data can then be recorded and stored for subsequent analysis. This input data is converted to a format usable for the software (or touchscreen, when software is not available).
Emergency stop button
This safety button cuts electrical power within the instrument in an emergency situation if you require the instrument to stop immediately during a test for whatever reason. This is an important safety feature on an instrument with the potential for rapidly moving parts, sharp components and high forces.
There is the option of a safety screen that cuts power to the arm when open, and allows movement when closed. Alternatively, instruments may be enclosed mechanically by a static shatter screen that is put in place before a test begins.
Mechanical and electronic stops are also used to protect the instrument itself. These prevent the loading arm moving past the end of its intended travel. For load cells, as well as overload and underload force limits programmed into the unit, stops are sometimes included in the load cell housing, preventing the load cell from damage.
Stop bar
When using fragile containers or test fixtures that may be damaged by excessive force, mechanical limits for the operation can be set using the top and bottom stops located on this bar
Buttons on this membrane provide the means to move the arm up and down at a choice of speeds. Lights indicate communication statuses.
A Texture Analyser is a versatile and essential tool providing detailed insights into the texture and physical properties of products. Understanding its key components and functions helps maximise its utility and effectiveness in various applications.
Why not request a Features and Safety poster for placement near your instrument to inform users:
Or if you have lost it, request a 167 page (pdf) in-depth manual to be sent to you.
There is a Texture Analysis test for virtually any physical property. Contact Stable Micro Systems today to learn more about our full range of solutions.
For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.
The TA.XTplusC Texture Analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.
No-one understands texture analysis like we do!
Get in touch to discuss your specific test requirements
 |  |  |
No comments:
Post a Comment