Sampling systems handbook and approval guide

• Previous page
• Table of contents
• Next page

4. Types of sampling systems

4.1 Sampling systems that are eligible for approval

In general, the CGC will give approval only to sampling systems that extract a complete and proportional cross-section of the grain stream (both height and width), proportionally reduce the sample size, and deliver the sample to the inspection area. (Exceptions are discussed in Section 4.3.) Samplers of this type are commonly referred to as cross-stream diverter-type samplers (Figure 4.1). The dividers and the delivery system must conform to manufacturer specifications and must be constructed of the industrial durability required to operate in the environment where the system is located.

CGC approval for any new sampling concepts will be based on the ability of the proposed sampling system to extract a two dimensional (height and width) section of the grain stream, proportionally reduce the sample size, and deliver the sample to the inspection area.

Figure 4.1 Cross-stream sampling

4.2 Arc-path cross-stream samplers

An arc-path cross-stream sampler is defined as sampler where the cutter rotates from a centre point and traverses the grain stream by following an arced path. These may be either flowing stream samplers or falling stream samplers (Figures 4.2 and 4.3).

Figure 4.2 Arc-path cross-stream sampler-flowing stream

Figure 4.3 Arc-path cross-stream sampler-falling stream

Arc-path samplers may be approved for official inspection purposes, provided that the cutter opening exposes a minimum of 1.9 cm (¾ (0.75) inch), measured perpendicular to the grain stream, as the cutter enters and exits the grain stream (see Figure 4.4).

Figure 4.4 Cutter opening requirement for arc-path cross-stream samplers

4.3 Non-conforming and previously approved samplers

Woodside samplers (Figure 4.5) strip/auger samplers (Figure 4.6) or point type samplers (Figure 4.7) that were previously approved by the CGC are non-conforming to these requirements and are no longer authorized to collect samples for official CGC certication of vessels and railcars.

At the discretion of the CGC, a non-conforming sampling system may be used to sample grain:

1. during a weigh-over provided that the sampling system is under the direct supervision of the CGC.
2. by the CGC, by 3rd party staff accredited by the CGC or by grain company staff certified by the CGC provided that:
   1. the sampled grain, either bulk or bagged is destined for shipment in a container,
   2. the sampling system has been reviewed and authorized by the CGC, and
   3. the sampling system is used and maintained in the manner deemed suitable by the CGC.

The following criteria will be used by the CGC in reviewing and authorizing sampling systems:

• The sampling tube may be either installed permanently in the grain stream or the tube may extend into the grain steam intermittently.
• Where the sampling tube extends into the grain, the tube must extend to at least 75% of diameter of the grain stream.
• The combined length of the sampler tube opening on the sampling tube must be at least 75% of the probe length.
• One sampling tube opening must be within ¾ of an inch of the spout wall where the product is flowing.
• The diameter the sampling tube opening must be at least ¾ of an inch.
• Automatic samplers must have an adjustable timer. Sampler timers may be either analog or digital, and must have a maximum 1-second dial or timer interval setting.
• The timer of a cross-stream sampler must be set to an interval not greater than 45 seconds.

Some examples of non-conforming (Figure 4.8) automatic samplers are:

Figure 4.5 Woodside sampler

Figure 4.6 Strip/auger sampler

Figure 4.7 Point type sampler

Figure 4.8 Non-conforming automatic samplers

• Previous page
• Table of contents
• Next page