Table 3-1: Tensile Strength and Collapse Load
Probe type Tensile strength Collapse load
0.16-in. (4 mm) diameter Minimum 2698 lb (12 kN) Maximum 3597 lb (16 kN)
0.24-in. (6 mm) diameter Minimum 6519 lb (29 kN) Maximum 7868 lb (35 kN)
Keep the following in mind when planning installation of the Rosemount 5300 in solid
applications:
• There might be considerable down-pull forces on silo roofs caused by the media, so the
silo roof must withstand the maximum probe tensile load.
• The tensile load depends on silo size, material density, and the friction coefficient.
Forces increase with the buried length, the silo, and probe diameter.
• In critical cases, such as for products with a risk for build-up, use a 0.24 in. (6 mm)
probe.
• Depending on position, forces on probes are two to ten times greater on probes with
tie-down, than on probes with ballast weights
(1)
.
• PTFE coated probes are not recommended for solid applications.
Guidelines for the tensile load from free-flowing solids acting on a suspended probe
without any tie-down or weight in a smooth metallic wall silo as shown in Table 3-2 and
Table 3-3. A safety factor of 2 is included for the figures. Consult your local Emerson
representative for more information.
Table 3-2: Tensile Load for Unanchored 0.16 in. (4 mm) Flexible Single Lead Probe, lb
(kN)
Material Probe length 49 ft. (15 m) Probe length 115 ft. (35 m)
Tank Ø= 10 ft. (3
m)
Tank Ø= 39 ft.
(12 m)
Tank Ø= 10 ft. (3
m)
Tank Ø= 39 ft.
(12 m)
Wheat 670 (3) 1120 (5) 1800 (8) 4500 (20)
(1)
Polypropylene
Pellets
340 (1.5) 670 (3) 810 (3.6) 2360 (10.5)
Cement 900 (4) 2020 (9) 2470 (11) 7310 (32.5)
(1)
(1) Exceeds tensile strength limit.
(1) The weight should not be fixed for probe 100 ft. (30 m) or longer.
Reference Manual Mechanical installation
00809-0100-4530 April 2019
Reference Manual 31
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