Probing considerations

by Emily Wilson
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"Shuttle train" loading is the current trend in the U.S.
grain industry due to the economic incentives offered by
the railroads. Although shuttle trains remain mostly a
U.S. railroad process, in other areas of the world, the receiving and shipping capacities continue to get faster and faster, particularly on barges and ships. Despite the fact that truck receiving capacities around the world are not at U.S. levels, trucks (or wagons) in many cases are taller and even larger
in capacity than U.S. trucks. This has placed an emphasis
on increasing the speed to unload trucks of various types
and to obtain accurate, representative samples in an expeditious manner.

A shuttle train will hold more than 11,000 tonnes of grain, and some facilities will load three to four trains per month. In most cases, grain is brought into the facility by trucks. For grain facilities looking to
improve sampling and receiving logistics, automatic truck probes can provide many
benefits over manual probe sampling.

For example, extra manpower is often required at harvest time in order to perform the manual probing process. With the demand to reduce the costs of manpower and an unavailable labor supply at this critical time, owners have found that they could speed up their probing process with automatic probes and eliminate the need for extra manpower.

Introduced in the 1970s, automatic truck probes have become very popular in the U.S. in the past five to ten years. As many grain companies become multi-national and as technology becomes more accessible, the use of automatic truck probes is beginning to spread rapidly. Brazil, Argentina, Mexico, Russia, Romania and Australia are just a few of the countries currently using automatic truck probes. Although the initial cost is significantly more than a manual hand probe, automatic probes can provide many benefits.


• Representative and repeatable sam-ples. Two types of probe tips, compartmentalized and core, are accurate and reliable in obtaining a sample from the vehicle. The compartmentalized tip operates like an automated hand probe and obtains samples from various "layers" in the load, pulling them into a collection cabinet via a vacuum system. The core tip contains an outer and inner tube and obtains a "cored" sample within the inner tube, where it is then pulled in by a vacuum to the collection cabinet. Neither type of tip "sucks" in the sample to prevent damage or degradation, and both have been type-approved through USDA tests. A consistency in the method of taking the sample produces grading results that are accurate and reliable.

• Less manpower. One person can run the probe from within the inspection station and, often, that person can weigh, test and make bin selection. In many cases, the probe operator can sample two lanes of traffic or run a dual probe setup.

• Efficient operation. With automatic truck probes, there are no sample containers to handle and the sample is delivered via a pneumatic system directly into the inspection room where testing equipment is readily accessible to make a quick analysis of the sample. Samples can be pneumatically drawn from several hundred feet away, which facilitates the logistics of truck movement in and out of the facility. An extended reach on the probe boom or a dual probe setup may be used to access all areas of a semitrailer without having to move it during the sampling process. In addition, an excess sample return system can be used to return grain after testing, thus eliminating the need to manually handle it.

• Improved safety. With the automated probe, no one is required to climb up on the truck to take a sample, eliminating the risk of someone slipping or falling off the truck. If manual probing is done, long hours of work cause fatigue and carelessness. Control of the automatic probe is done through a control panel in the office.


Most manufacturers of automatic truck probes offer several models that are either electrically or hydraulically operated. In the selection process, several operational and application questions should be considered.

How many trucks per day will be sampled? There are light-duty probes and heavy-duty models. When you have a high volume of trucks, especially semitrailers hauling over 30 tonnes of grain, a faster sampling process and a heavy-duty probe may be required. If a two-lane sampling pattern is used, the probe can be designed to accommodate a 330° rotation.

What type of trucks will be sampled and what distance will they have traveled? If the volume is primarily semitrailers and they have traveled a good distance, the grain will be more compacted and require more penetration power. This becomes a very important factor when the boom has been extended to reach a sampling point. Taller trucks may require a longer probe tip to reach the bottom. With this comes additional loading pressure, referred to as "KIP" loading, on the probe structure, so a heavier built probe may be required.

What commodities will be sampled? Whole grains are much easier to sample than meals and feed stocks. Subsequently, the type of probe tip used may be important. When handling meals and light materials, the use of a cyclone system above the collection cabinet is recommended. Meals will tend to build up in a sample line and may need to be flushed between different commodities.

Where will the probe be located? If the probe is close to the inspection office, transport of the sample via the pneumatic system is fairly simple. As the distance becomes longer and there are more bends and turns, the pneumatic system has to have more power. The size of the pneumatic line is also critical. Pulling the sample in a manner that does not cause damage or degradation needs to be carefully considered.

Can the operator see the top of the truck being sampled? If he can’t, a remote camera or mirror may be used to operate the probing process.

Careful, up-front planning when considering the selection and installation of an automatic truck probe will help ensure that you speed up your receiving operation while maintaining an accurate and repeatable sampling process.