Soil Testing Machines Lab Equipment Manufacturer, Supplier and Exporter in India

What this range covers

About fifty items, coded STM-0001 onwards, covering the four families of soil laboratory work. Index and classification: a liquid limit device, plastic limit test, shrinkage limit set, linear shrinkage mould and cone penetrometers including a semi-automatic version. Particle size: grain size analysis by the pipette method, particle size by sedimentation using a hydrometer, soil hydrometers and a high speed stirrer for dispersion. Moisture and compaction: speedy, rapid and infrared moisture meters, and Proctor needles in spring and hydraulic types. Strength and permeability: pocket and proving-ring penetrometers and falling head and universal permeability apparatus.

Three notes on our catalogue data. One code in this listing appears twice against two different products - a high speed stirrer and a grain size pipette apparatus share a number - so on this listing order by name, not by code, and ask us to confirm both on the proforma invoice. One record further into the listing is a gold testing machine, which has strayed in from another range entirely. And one penetrometer has the place name in its title misspelled; the instrument is the standard proving-ring type.

Cup or Cone?

This is the first question to settle, and it decides which apparatus you buy, because the two standard methods for liquid limit do not give the same number for the same soil.

The percussion cup method - a brass cup raised and dropped a set number of times until a groove closes - and the cone penetrometer method - a standard cone allowed to penetrate the soil for a fixed time - are both long established, both in current standards, and both perfectly valid. They simply answer the question differently, and a liquid limit reported without saying which method produced it is incomplete. The cone method is generally the more repeatable between operators, because the cup method depends on the rate of blows and on the groove being cut cleanly; the cup method remains specified in a great many national standards and in a great many examination syllabuses.

And whichever you choose, the plastic limit is still a hand method - rolling a thread to a standard diameter on a glass plate - so it is operator-dependent by nature and benefits from two analysts agreeing on a sample. Together the two limits give the plasticity index, which is the figure every soil classification system is built on.

Particle size: the slow experiment that rewards a stable room

Sieving handles the coarse fraction, but silt and clay need sedimentation - a hydrometer or pipette measuring how much material remains in suspension as time passes, with the size inferred from the settling rate. The arithmetic is simple and three practical matters decide whether the answer is right.

Temperature. The settling rate depends on the viscosity of water, which changes appreciably with temperature, and the test runs for hours. A sedimentation cylinder standing in a room that warms through the afternoon produces a grading curve with a temperature error baked into it. Ask whether a constant temperature bath is offered, and if not, keep the cylinders away from windows and heaters and record the temperature at each reading.

Dispersion. Clay particles flocculate, and flocs settle as though they were sand. That is what the dispersing agent and the high speed stirrer in this listing are for. Ask what dispersing agent the method specifies, whether it can be bought locally, and how long the stirring period is - under-dispersed soil reads coarser than it is, which is the direction that flatters a material.

Reading the hydrometer. The stem is read at the top of the meniscus and a correction applied; the correction, the meniscus habit and the zero check against dispersant solution all have to be taught. Ask what hydrometers are supplied, to which standard, and whether a calibration certificate comes with them.

Moisture content: three quick methods and one reference

Four instruments here measure moisture, and they divide into quick field methods and the laboratory reference.

The reference is the oven. Moisture content is defined by weighing, drying to constant mass and weighing again, and every quick method is calibrated against it. A soil laboratory should own a drying oven and a balance and should check its quick meters against oven results on its own soils, periodically and after any repair.

The calcium carbide method - the speedy meter - works by reacting the water in the sample with a reagent and reading the gas pressure produced. It is fast and genuinely useful on site, and it carries two conditions. The reagent reacts with water to produce a flammable gas, so the reagent must be kept dry and sealed, the vessel is vented away from ignition sources, and the reagent is a restricted item for air transport - ask us about shipping it, or source it locally. And the reading depends on the soil type, so a calibration against oven results for each soil is what makes the meter trustworthy.

Infrared and rapid meters are faster still and more sensitive to sample preparation and to the material. Ask the range, the resolution, the sample mass each needs and what calibration arrangement is provided.

Permeability and penetration

Two permeability units are listed, and the choice follows the soil: a constant head arrangement suits coarse, free-draining material and a falling head arrangement suits fine material, which is why the universal unit exists. Three things decide whether a permeability result means anything, and all three are method rather than machine: the specimen must be saturated, and trapped air invalidates the measurement, so de-aired water and slow saturation from below are part of the procedure; the specimen density and the packing procedure must be recorded, because permeability changes with compaction; and the water temperature must be noted, since viscosity again enters the calculation. Ask whether de-aired water provision, a manometer board and a timer are included.

The penetrometers - pocket, proving ring and the Proctor needles - are index and control instruments rather than design tools: they give a quick indication of consistency or of compaction resistance, useful for site control and for checking uniformity across a fill. Ask the range of each, what the proving ring calibration is and when it was certified, and what spare needles and points cost, because they wear and a worn point reads low.

What to ask for on the quotation

The standard and version each item is built to, named explicitly; for the liquid limit device, drop height, base specification and grooving tool; for the cone, mass, angle, penetration time and release mechanism; hydrometers to which standard and with what certificate; dispersing agent, its availability locally and the stirring arrangement; for permeability, head arrangement, de-aired water provision, manometer board and specimen sizes; for the moisture meters, range, resolution, sample mass, calibration arrangement and - for the carbide method - reagent supply and transport position; for the penetrometers, ranges, proving ring certification and spare points; moulds, tools and consumables with prices; bench space and services; nominal voltage, frequency and plug pattern for the powered items; and the warranty and local service position. For any certification stated here, contact us for the latest copies of the relevant certificates before you tender on it.

Related ranges: concrete testing machines, cement testing equipments and bitumen testing instruments for the rest of a materials laboratory, surveying instruments for the field side, civil engineering lab equipments for triaxial, shear and consolidation testing, and universal testing machines for the load frames those tests need. The full set is listed under testing machines. For a quotation, tell us the destination country, the standards you work to, whether the laboratory is for teaching or for commercial testing, and - first of all - whether your liquid limit method is the cup or the cone.

Frequently asked questions

Do the cup and cone methods give the same liquid limit?

No. In the cup method a brass cup is raised and dropped a set number of times until a groove closes; in the cone method a standard cone penetrates the soil for a fixed time. Both are in current standards, but they answer the question differently. The cone is generally more repeatable between operators, because the cup depends on the rate of blows and a cleanly cut groove. For a commercial laboratory, calibration of drop height, cone mass and timing are the figures an assessor checks. The plastic limit remains a hand method, so have two analysts agree on a sample.

How do we get reliable particle size results by hydrometer or pipette?

Control three things. Temperature: settling rate depends on water viscosity, which changes with temperature over a test lasting hours, so use a constant temperature bath if offered, keep cylinders away from windows and heaters, and record the temperature at each reading. Dispersion: clay flocculates and flocs settle like sand, which is what the dispersing agent and the high speed stirrer are for; under-dispersed soil reads coarser than it is. Reading: the hydrometer is read at the top of the meniscus with a correction and a zero check against dispersant solution. Ask which hydrometers are supplied and what calibration documents come with them.

Can a speedy moisture meter replace the drying oven?

No. Moisture content is defined by weighing, drying to constant mass and weighing again, so the oven is the reference and every quick method is calibrated against it. A soil laboratory should own a drying oven and a balance and check its quick meters against oven results on its own soils, periodically and after any repair. The calcium carbide speedy meter is useful on site, but its reagent produces a flammable gas with water, must be kept dry and sealed, and is restricted for air transport, so ask about shipping or source it locally. Its reading also depends on soil type.

Which permeability apparatus suits our soils?

The choice follows the soil. A constant head arrangement suits coarse, free-draining material and a falling head arrangement suits fine material, which is why a universal unit is listed alongside the falling head apparatus. Three things decide whether a result means anything, and all three are method rather than machine: the specimen must be fully saturated, since trapped air invalidates the measurement, so de-aired water and slow saturation from below are part of the procedure; specimen density and packing must be recorded; and water temperature must be noted. Ask whether de-aired water provision, a manometer board and a timer are included.

What are the pocket penetrometer, proving-ring penetrometer and Proctor needles for?

They are index and control instruments rather than design tools. They give a quick indication of consistency or of compaction resistance, which is useful for site control and for checking uniformity across a fill, but they do not replace laboratory strength tests. The Proctor needles are listed in spring and hydraulic types. Ask the range of each instrument, how the proving ring is calibrated and when it was last calibrated, and what spare needles and points are available, because points wear and a worn point reads low. Plan for replacing them as a routine consumable.

Why does this listing ask us to order by name rather than by code?

Because one code appears twice against two different products: a high speed stirrer and a grain size pipette apparatus share the same number. Order those two by name and have both confirmed on the proforma invoice. Two other catalogue faults are worth knowing: a gold testing machine has strayed into this soil range from another range entirely, and one penetrometer has a misspelled place name in its title, although the instrument itself is the standard proving-ring type. When in doubt, quote both the code and the full product name in your enquiry.

Key takeaways

• Method before apparatus: cup and cone give different liquid limits, so buy the method your standard or examination names.
• Plastic limit stays a hand method: thread-rolling is operator-dependent, so have two analysts agree on a sample.
• Control sedimentation temperature: viscosity shifts over a test lasting hours, so record the temperature at every reading.
• Disperse fully: under-dispersed clay reads coarser than it is, the direction that flatters a material.
• The oven is the reference: check speedy, rapid and infrared meters against oven results on your own soils.
• Saturate permeability specimens: trapped air invalidates the result, so de-aired water and slow saturation from below are part of the method.

About this page

Ray Export is a manufacturer and exporter of laboratory, scientific and educational equipment based at Plot No. 449, HSIIDC Industrial Area, Saha, Ambala, Haryana 133104, India. Enquiries: [email protected], +91-9817319615.

Written by Palak Mall, Senior Content Writer. Technically reviewed by Arvind Kumar, Lab Equipment Specialist, 12+ years in laboratory and testing instrumentation. Last updated: 17 October 2026.

Specifications for the STM items, including drop height, cone mass and angle, hydrometer type, moisture meter range and resolution and permeameter specimen sizes, are confirmed in writing on the quotation, together with the standard each item is built to. For calibration documents or certificates, contact us for the latest copies of the relevant certificates. No price is quoted on this page. Listing note: one code is shared by two different products, a high speed stirrer and a grain size pipette apparatus, so order those by name; a gold testing machine is misfiled in this soil range; and one penetrometer title carries a misspelled place name.