Factors for Proper Use of Sand Probe Elements
For Sand Erosion Probes to perform effectively, two factors must be taken into consideration.
1. The Placement of the Probe
The Sand Erosion Probe must be placed in the area of Maximum Velocity. In most cases this is approximately 10 pipe diameters, or an average of two (2) feet, downstream from a choke. This will allow for maximum velocity to erode the probe and allow for turbulence to dampen and flow to be even all the way across the pipe. This location should be before the first 90°turn in the flowline.
The probe should also be placed in the flow stream so that the flow is 90°from the probe length.
2. The selection of the element.
There are three factors to consider in the selection of the sand erosion probe:
- Length
- Material
- Wall Thickness
Length
HLR Controls has developed a standard probe length for 2, 3, 4, 6, 8, and 10 Flowlines. Sand Probes ordered for these flowline sizes will fit all schedule pipe with a standard 1/2” NPT threaded weld-o-let. HLR Controls should be contacted directly for any installation not using standard piping with a 1/2” NPTweld-o-let. These installations would include use of instrument blocks or other flanged
applications.
Material
Maximum correlation of erosion data between flowlines and probes is achieved by installing a probe of the same material as the flowline. For standard installations, HLR Controls recommends the use of 7620 Series Sand Probes manufactured of 4140 alloy steel. Applications that involve severe service conditions such as high temperature, high velocity, or high pressure require the use of HLR 7620MR Series Sand Probes. The 7620MR Series Sand Probes are machine of solid bar stock 410 stainless steel. In addition to 4140 alloy steel and 410 stainless steel, HLR Controls also manufactures probes in the following materials:
4140 "DD" Trim - same as 4140 but heat tempered and quenched for sour oil and gas.
410 "FF" Trim - same as 410 SS but heat tempered and quenched for sour oil and gas, and corrosion service.
316 Stainless Steel - good for sour oil and gas in the annealed condition with RHC of 22 or less.
Duplex Stainless Steel - good for sour oil and gas and corrosion service.
Wall Thickness
Since several probes may fail before the piping must be repaired, greater accuracy can be obtained with a greater number of probes between overhauls. This means the probe wall needs to be thin. The limit on how thin the wall can be is the amount of pressure that must be held. If the wall is too thin, the tube will collapse from external pressure.
HLR Part Number
| Operating Pressure
| Collapse Pressure
|
| HLR 7620-pipe size-025 | 400 - 1,000 PSI
| 8,076 PSI |
HLR 7620-pipe size-035
| 1,000 - 2,160 PSI
| 11,306 PSI
|
HLR 7620-pipe size-050
| 2,160 - 5,000 PSI | 21,560 PSI
|
HLR 7620-pipe size-065
| 5,000 - 10,000 PSI | 26,988 PSI |
| HLR 7620MR-pipe size-025 | 400 - 1,000 PSI
| 5,873 PSI |
HLR 7620MR-pipe size-035
| 1,000 - 2,160 PSI
| 8,223 PSI
|
| HLR 7620MR-pipe size-050 | 2,160 - 10,000 PSI
| 15,680 PSI
|
HLR 25 Series
| up to 15,000 PSI
| 45,473 PSI
|
NOTES:
- HLR 7620 Series External Pressure Design Criteria ASME Code Section VII, Div1.,UG-28through UG-30, Code B31.3 Section 304.1,3
- HLR 25 Series Design Criteria per API Bulletin 5C3
