BORELINE FLEXIBLE RISING MAIN > QUESTIONS & ANSWERS |
1. Will the riser withstand the forces and stresses involved in pumping?
It can operate continuously at pressures up to 25 bar with a good safety factor over its life while also maintaining its design tensile load. In practice most wells operate far below the design pressure and tensile loadings of Boreline thus giving safety factors way in excess of the requirement.
2. Abrasion resistance. Will Boreline cope with sand in the pumped water?
The materials used in Boreline are particularly resistant to abrasion and have been shown to resist particulate matter such as sand extremely well.
3. Can Boreline tolerate dragging across the ground?
Normal dragging and abrasion encountered during riser installation causes no visible damage. Care should, though, be taken to avoid any snagging of the hose on the well head or any sharp objects in the vicinity. (Contact with the ground, or other potential contaminants must be avoided for potable water applications.)
4. Temperature of Operation. What water temperatures can be tolerated?
Boreline will safely handle water up to 53°C - this includes the vast majority of likely applications. (23°C is the maximum for potable water applications.) Use of Boreline in water temperatures above 50°C will reduce its working life - For advice refer to your Boreline distributor.
5. Water Quality. Is Boreline restricted with respect to Water Quality?
A pH range of 4-9 can be safely tolerated for pumped water temperatures below 30°C. At temperatures between 30°C & 55°C the recommended pH range is from pH5 to pH9. Boreline is resistant to a wide variety of chemicals, details of which are available on request.
6. Failure of the Riser. How can I retrieve the pump if the riser fails?
In the event of very severe riser misuse, Boreline is designed to fail safe. i. e. if the riser bursts it retains its longitudinal strength and the pump can be withdrawn attached to the riser.
7. Can I use the riser for applications other than rising mains?
Boreline can be used for most submersible pump operations and may also be used as a delivery hose for a wide range of fluids. However, Boreline is designed to a higher specification than most other delivery requirements and for more general application you should contact your local Flexible Pipeline distributor or the manufacturer for advice on the most economic systems.
8. What couplings are available?
A range of reusable couplings is available specifically designed for on-site attachment. The stainless steel or aluminium bronze couplings (& High Tensile Polymer in 1", 1½" & 2" sizes) complement the riser, having a good resistance to aggressive water and the benefits of long life with low maintenance.
9. How do the couplings work?
Couplings are double ribbed with clamps to ensure there can be no movement in any direction.
10. How strong are the couplings? Can the riser pullout?
Provided the manufacturer's instructions are followed, the couplings are stronger than the riser. The riser will tear or burst before the couplings lose their grip.
11. How's the power cable attached?
Normally cables supplying submersible pumps are attached diametrically opposite to the ridge specifically provided along the outside of the riser. The cable is attached using straps tied in a clove hitch as shown on page 18. When the pump and riser assembly are a tight fit within the casing or in dog-leg wells. the power cable should be protected particularly as it passes over the top of the pump. For absolute stability the use of a spider or centralising device is recommended.
12. What if the cable is heavy or I have several items to attach?
If a safety cable/dosing tube/dip tubes, etc. are included in any installation these may be secured to the riser in the same way as the power cable or, if preferred, attached to the power cable. On lowering into the borehole care must be taken to ensure Boreline takes all the load.
13. Can I retain the pump's non-return valve?
In order to make removal of the pump and riser from the well easier it is important that the water is allowed to drain from the riser beforehand. If no Break-Off Plug is fitted to permit this, the pump's non-return valve should be removed or drilled to allow the riser to drain whenever the pump stops - a non-return valve fitted at the wellhead will prevent the surface system from draining back through the pump. (A relief valve should also be fitted to prevent vacuum from collapsing the Boreline.) Providing you do not contravene the pump warranty, we recommend that a 6 mm (¼") hole is drilled in the non-return valve retained in the pump. If further advice is required consult your distributor.
14. What if I haven't fitted a Break-Off Plug and I forget to drill or remove the non-return valve so the riser remains full of water?
This is not detrimental to performance but care must be taken on lifting the riser full as the standard lifting clamps may not be sufficiently rated for the loading. Details of pump weight, riser size and depth should be passed to your distributor who will advise on lifting methods.
15. How can I earth my pump with your riser?
Pump manufacturer's recommendations should be followed with regard to the equipment and its electrical safety. If no other guidance is given, we would recommend using a separate earth cable from the pump to a suitable surface earthing point.
16. Does the pump torque twist the riser?
At pump start-up there is a partial rotation of the riser in the area of the pump which ceases immediately the pump speed increases and the riser fills to become a rigid system. This is not detrimental to the performance of the system, merely a consequence of the elastic nature of the riser. This property has major benefits in the resistance of shock loadings.
17. Steel risers sometimes suffer from solid deposits building up-how does Boreline perform?
In operation the riser will flex continually - though imperceptibly. On stopping the pump the riser will drain and collapse to its original lay-flat state provided the non-return valve has been removed or drilled out. Because of these features solid encrustation cannot gain a grip on the Boreline.
18. Does slime and other algae-based deposit build-up inside Boreline?
One feature of the Boreline material is that it does not support algae growth. Tests performed by the manufacturer and repeated by the Water Research Centre (U.K.) have shown that algae will not grow on the riser material.
19. What pressure losses can be expected with Boreline?
Pressure losses through Boreline are lower than with any other type of riser. This Super hydraulic performance is achieved by the avoidance of internal deposit build-up. (i. e. Friction factors claimed for rigid pipe are valid only in new systems and corrosion / sedimentation in use will soon have a detrimental effect.) Being of flexible construction Boreline is designed to swell under pressure. This flexibility allows increases in the diameter, thus further reducing head loss as compared to rigid risers.
20. Will Boreline and its couplings stand up to long term use?
Extensive laboratory trials and several years practical experience in hundreds of wells world-wide has shown that Boreline and its couplings are capable of long life in conditions where steel riser would quickly fail. The recommendations made in this literature generally assume that the most extreme conditions will apply simultaneously and continuously. In practice this is generally not the case. Safety margins are therefore very high.
21. How can you be sure of the precise pump setting?
By careful design of the Boreline reinforcement, the extension of the riser has been minimised to balance the extension effect of axial loads against the reverse effect of internal pressure. The precise extension of the Boreline riser can be predicted with reasonable accuracy and, as a rule, will not exceed 2%. The can riser swell radially up to 15% at the maximum operating pressures which benefits hydraulic efficiency.
22. Can the Boreline withstand the surge pressure due to sudden valve operation?
The ability of Boreline to safely expand under pressure minimises the effect of surge pressure. This is a major advantage over rigid risers where 'water hammer' can be a serious problem.
23. Who has approved the riser?
The potable water qualities of the riser have a number of national approvals including United Kingdom, Germany, South Africa and Australia. Boreline, has been installed in many countries and in a wide range of operating conditions over the last few years. It has proved to be a revolutionary solution to aggressive water problems and when the additional installation and handling costs of steel pipe are considered, it is a cost effective solution in most water well applications.
24. Boreline - Does Chlorine affect its properties?
Under known conditions of application to the well water, chlorine has no detrimental effect on the mechanical performance of the riser. Use of high concentrations should be discussed with your local distributor.
25. What guarantees do we have with Boreline?
The manufacturer provides a warranty of 5 years against materials and manufacturing defects thus : If within this time from ex-works despatch any defect arising from faulty workmanship or material is discovered the goods will be replaced free of charge, provided that the customer notifies the supplier immediately. Departure from recommended operational usage and use of materials not supplied by the company will invalidate this. The warranty does not cover incidental costs incurred in removal and installation of the riser.
26. How must Boreline be stored?
Boreline should be stored out of direct sunlight between -20°C and +40°C to ensure maximum working life. Exposure to humid or damp conditions is not detrimental. (Where Boreline is to be used for a potable water application, measures should be taken to keep it clean at all times or to disinfect fully before use.)