One of the most common types of industrial scales is the bench scale. Generally, they are available in capacities ranging from about 10 pounds up to approximately 150 lbs. As a rule of thumb, the lighter the capacity of the scale, the higher the resolution of the display. For example, a ten pound capacity scale may be able to display increments as small as 0.001 lb. Whereas a one hundred pound scale has ten times the capacity, it may have only one tenth of the readability, resulting in display increments of 0.01 lb.

Although the readability of the bench scale is important, the overall accuracy is a defining value. Arlyn Scales produces bench scales that provide levels of accuracy that are suitable for industrial measurement. Many of the important design elements that result in good accuracy can be traced to the electronic sensors of the digital scale. These sensors must be very rugged, or they will be quickly damaged in an industrial environment. But they must also be very sensitive. Additional characteristics include the ability to produce correct results over a wide range of temperature. For these reasons, Arlyn Scales uses a special stainless steel alloy in the production of their weight sensors. Additional electronics are built into the sensor to detect the ambient temperature of the bench scale, and to adjust the electronic output of the sensor to compensate for temperature variations.

Of course, the bench scale must also include accurate digitizing circuitry to convert the sensor output into a digital value for the display. These circuits must react quickly to any change in weight on the scale platform, while also filtering out the results of air movement and vibration.

But sometimes, the problem at hand cannot be solved with an off the shelf digital scale. For example, the task may be to determine the center of gravity of a non-symmetrical item, such as a part for a jet engine. Or the digital indicator of a drum scale must show the amount of material left in the drum in gallons or liters, instead of pounds. Or the item to be weighed has a shape that does not allow it to be easily placed on a standard industrial scale platform.

There are just a very few industrial scale manufacturers that are capable of producing a custom scale. Arlyn Scales designs their own load cells, digital indicators and scale platforms. They are able to produce a load sensor that can fit in a particular space that is available. A custom designed platform may be required to accept the load cell, and receive the type of load that is applied. The digital indicator may need to communicate the data to a remote computer system, or provide printouts in a special format. These custom weighing systems and custom scales may be produced as a single unit, or may be designed to be incorporated into another company’s own equipment. This will allow weighing functions to be made available in types of equipment that never previously had that type of capability.

A small container of liquid or liquefied gas may be weighed on a bench scale or cylinder scale. Larger tanks will be weighed on platform scales, drum scales or floor scales. In all of these cases, a highly accurate industrial scale can detect very small changes in the weight of liquid in the container. As the material is dispensed, some types of electronic scales, such as those manufactured by Arlyn Scales, can keep a record of the remaining weight at each moment of time. By calculating the change in weight over periods of time, the flow rate may be calculated. This rate may be shown as pounds per minute or hour. If the specific gravity of the liquid has been input, the industrial scale can also display this in gallons or liters per minute or hour.

The flow rate calculation must have the ability to average small changes in the dispense rates. Even with excellent scale sensitivity, this rate must be high enough for change in weight to be measure able in reasonably short periods of time. If the user can accept a longer time to achieve a displayed result, then the scale will be able to measure even slower flow rates. It is important that an electronic scale with the correct capacity be chosen for the size of the container that is being weighed.

Specialty weighing and sorting devices have been designed by Arlyn Scales for this industry. The pig sorter consists of an inner cage with entry doors and exit doors, along with some sorting gates. The inner cage is suspended from load cells and hung from an outer cage. In normal operation, the entry door starts in the open position. An electric eye detects when an animal enters the cage. The entry door closes, and the load cells send the weight signal to a scale indicator. When a stable reading has been recorded, the sorting gates will swing into position to send the animal to the desired feed area. If the animal is gaining weight slowly, it will be directed to feed that will provide it with additional nutrition. If the animal has gained weight faster than the others, it will eat from lower calorie feed.

The pig sorter collects data from each animal as it travels through. This data can be collected internally with the scale indicator, or sent to a USB memory stick. Not only is each individual weight recorded, but it is sorted by group. This data is used to calculate the average weight gain of all of the animals in the batch. More advanced options allow this data to be transmitted from the pig sorter to the Internet. Those who need to read this data, when given the proper authorization, are able to access it from any Internet connected computer.

Furthermore, many people who use wheelchairs have a variety of medical issues. It is often important to monitor the weight of the patient. This may be to make sure they are receiving the proper nutrition and are not losing weight. Or quite the opposite, it may be important that there is no inappropriate weight gain caused by fluid retention or other issues. For this reason, a wheelchair scale is an important health care device.

An important feature that should be included in a wheelchair scale is a platform that is large enough to easily move the wheelchair onto and off of. It should also accommodate a variety of different size wheelchairs. Some models are designed with a heavy enough capacity and large enough platform to accept bariatric wheelchairs. The platform should also have a very low profile. The allows the ramps going up to the platform to have a low slope, making it easy to roll up and down. The ramp can also be fairly short, so the scale and ramp assembly will not take up too much space.

The digital indicator will show the total weight of the wheelchair and patient. These electronic scales include the ability to enter the tare weight of the wheelchair. This can then be subtracted from the total gross weight, yielding the weight of just the patient. Furthermore, the digits on the indicator should be large and clear, making it easy for both the patient and scale operator to see the weight results. Some wheelchair scales include data output capability. Patient weight can be forwarded to a computer database to be entered into their records. This allows weight trends for the patient to be examined.

Equipment that is use in these areas must be specially designed so that they cannot cause a spark or flame or very high temperature, even if there are compound failures of that equipment. Generally, these items may be considered to be intrinsically safe.

Intrinsically safe scales are used in hazardous areas where items must be weighed. While it is important, of course, for these devices to be accurate, it is essential that they be designed for safety. There are a number of rating levels that note the level of safety. There are also a variety of rating organizations.

The most common and effective method of powering an intrinsically safe scale is with a special battery pack. This pack must be protected so that it cannot provide a large amount of energy within a short period of time.