EN 58-2012 pdf download.Bitumen and bituminous binders – Sampling bituminous binders.
8.1.2 Sampling probe. If samples shall be taken from a flowing material, it is convenient to take side- stream samples using a sampling probe installed in the delivery pipe. The sampling probe shall be Installed in an upward-sloping section of the pipe or on the pressure side of the pump, or in the case of a gravity-fed system in a completely full section of pipe. The internal diameter of the sampling probe shall be less than 118 of the internal diameter of the delivery pipe, and its opening shall be approximately central in the pipe facing upstream. The sampling probe shall be equipped with a stop-valve. For very viscous material, it may be advantageous to arrange for the movable parts to be totally immersed in the material. Figures 1 (for pipes without pressure) and 2 show examples of suitable arrangements; the arrangements shown in Figures 1 and 2 shall be equipped with a protecting box In the sampling device.
Necessity to draw off material should be assessed (see 8.1 .1 above).
If a representative sample is required, either sampling can be continuous, or spot samples can be taken by opening the stop valve at equal time intervals throughout the period of flow.
This method is usable for flowing material. For a well mixed material, a spot sample. usually taken from the middle third of the material, can be regarded as a representative sample. For material which Is not well mixed, a sample taken during the whole period of flow, or a composite sample formed from at least three spot samples, shall be used.
8.1.3 Sampling valve in container walls. Sampling valves in the walls of heated containers can advantageously be installed so that the movable parts and the pipewor1 are as far as possible within the heated material. Figure 3 shows a suitable arrangement. For this arrangement, a simple cover shall be provided for the sampling device.
Necessity to draw off material should be assessed (see 8.1.1 above).
The sample shall be drawn off into a suitable clean container or bottle.
This method is suitable for all liquid materials, whether hot or cold, and especially for containers larger than 50 m3. For a well-mixed material, a spot sample, usually from the middle third, can be regarded as a representative sample.
For material which is not well mixed, layer samples shall be taken from at least the top, middle and lower thirds.
8.1.4 Sampling valve in delivery pipes (see Clause 6). To allow side-stream samples to be taken from narrow delivery pipes, a sampling valve can be installed in place of a sampling probe in the supply line. The sampling valve shall be installed in an upward-sloping section of the supply line or on the outlet of the pump. For systems flowing under their hydrostatic head, the sampling valve shall be installed on the pressure side of the supply pipe.
Necessity to draw off material should be assessed (see 8.1.1 above).
easily accessible 3-way valve Is convenient, The cock shall have an internal diameter appropriate to the size of the pipe, and shall be installed with the sampling outlet pointing downwards. The length of the pipe leading to the outlet shall be as short as possible. Figures 6 and 7 show an example of a three-way valve.
Necessity to draw off material should be assessed (see 8.1.1 above).
If a representative sample is to be obtained, several spot samples shall be taken by opening the three-way valve at equal time intervals over the whole supply period.
This method Is suitable for all liquid materials in narrow pipes.
For well-mixed materials, a spot sample can be regarded as a representative sample, but for materials which are not well mixed, a composite sample shall be formed from at least three spot samples.
If a well-mixed material is unloaded from a container vehicle, the sample shall be taken during the delivery of the second third of the material.
8.2 Sampling using submersible equipment
The procedures described in 8.2 use permanently installed sampling devices and the depth from which the sample is taken is therefore fixed in advance without reference to the depth to which the tank may be filled at the time of sampling. By the use of submersible equipment, samples can be taken from any depth.
8.2.1 Weighted sampling can. A weighted sampling can shall be used for sampling liquid materials and a typical example for high viscosity materials is shown in Figures 8 and 9. For very fluid materials, a weighted sampling can of the type shown in Figure 10 may be used.
Clean the sampling can and close it with the bung; lower it by the suspension to the chosen depth in the tank. Take a layer sample by withdrawing the bung with a short jerk on the suspension. The sampling equipment shall then be held at a constant depth until it is full as indicated by a cessation in the formation of air bubbles.
NOTE The opening in the flask or can is small in comparison with its volume, so that there is no significant contamination of the sample by material from other layers during the subsequent slow withdrawal of the sampling appliance.
The method is suitable for sampling fluid material in a storage tank. For well-mixed material and storage tanks of up to 50 m3 capacity, one spot sample, usually taken from the middle third, can serve as a representative sample. For less well-mixed material and storage tanks greater than 50 m3 capacity, samples shall be taken from at least the top, middle and lower third of the material.
8.2.2 Surface sampling can. A surface sampling can shall be used to take top surface samples of liquid material in tanks up to 50 m3 capacity, e.g. road tankers. This consists of a clean, open-top can, of suitable diameter, in a holder, e.g. a laboratory stand, which also serves as a ballast weight. The length of the holder shall permit the can to be lowered through the tank opening, and submerged below the surface of the material. Fiqures 11 and 12 show an example of a suitable holder.EN 58-2012 pdf download.
EN 58-2012 pdf download
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