triple beam balance

triple beam balance

In any scientific laboratory that needs exacting standards for measurements such as mass, a triple beam balance has found its place. This precision instrument has been an industry standard mass/weight measurement device for nearly two centuries, and has not changed much since its first manufacture. The triple beam balance has three measuring beams, each scored with numbering to indicate the weight as the sliders, or decades, are slid along their length to zero the balance.

These accurate scales are used to measure the weight of dry and liquid materials. The most common of these scales takes loads on a tray at one end of the scales; others have a tray or pan suspended by wires beneath the weighing point. The scales have an adjustment knob at the end to facilitate “zeroing” the scales, or setting the pointer to the level mark on the opposite end of the scale from the weighing point.

The beams are normally marked off in hundredths, tens, and single standardized grams. The scales can also come in metric measurements, being marked off from tenths of milligrams to even kilograms. There are triple beam balances made for very heavy loads, and scales used for extremely delicate measurements.

A good triple beam balances for the scientific laboratory must have allowances in the zero adjustment for temperature because the metals used in the construction may contract or expand and give erroneous results, especially in a scientific measurements of micrograms or less. The measurements should be easy to read and the sliders, or decades, should be functional and smooth in action.

Dry materials measurement for use in making up reagents, for example, should also have the option of using a scooped container for easy pouring of the materials in a mixing container. This may require a “tare” beam, or a beam that can measure and zero any containers used in the initial weight measurement. This method is simple: Placing the container on the scale tray, the weight of the container is then zeroed with the tare beam. After the needle reads “zero”, the material to be weighed can now be placed into the newly zeroed container, thus giving the weight measurement of only the dry materials.

For liquids, the triple beam balances must not be disturbed by the moving liquids in their container. A good, sturdily built scale is necessary for this, so as not to have erroneous measurements. The scale must be easy to use and read all around and sensitivity should be considered when measuring liquids.

Hanging tray triple beam balances are useful in the laboratory setting because the tray can be removed to pour off whatever materials were weighed. This is excellent for making up reagents or media, as multiple trays can be used at any given moment without concern for constant cleaning. Disposable trays may also be used, increasing efficiency and productivity.

Triple beam balances are used in nearly every scientific laboratory setting. Pathologists measuring organs and tissue from autopsies, chemists measuring dry elements for mixing, pharmacists measuring powdered medications, and even geologists measuring samples taken from remote regions. All benefit from these versatile and dependable measurement devices.

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