Horizontal pumping systems are not governed by API or ANSI classifications (such as API 610). Manufacturers have been completely free to develop their own system designs, without being forced to follow any industry guidelines. This has resulted in true innovation, as evidenced by our HOSS thrust chamber design, but can have consequences when servicing installed equipment. There are many different pump hydraulic designs and a wide variety of dimensional standards offered by the various manufacturers. Certain manufacturers have even produced multiple generations of design standards and product lines during their history. Bolt patterns, shaft sizes, and even rotation direction commonly vary from manufacturer to manufacturer.
Some horizontal pump providers use this lack of standardization to convince customers that the only feasible option is to contact the original equipment manufacturer (OEM) when servicing or buying replacement parts for installed units. This approach is not in the best interest of the end-user however, especially with the poor service level and long delivery times that are common in the market today.
HOSS believes that retrofitting and upgrading existing horizontal pump systems can be done economically while also increasing reliability. We have worked with many customers that have stopped recurring failures by working with our team of engineers to fully diagnose the root cause and upgrade their pump system to permanently mitigate failure modes. Examples have included changing metallurgy, upgrading pump or motor bearings, and adjusting the hydraulic design point. Root cause failure analysis is a structured process that requires the careful collection of evidence, a thorough review of operational history, and technical competence. We take this process seriously at HOSS and are passionate about permanently fixing problems through engineering analysis.
Retrofits usually fall into three primary categories: pump replacement, thrust chamber retrofit, and motor replacement.
Pump replacement requires dimensional and hydraulic validation of the existing pump, with a detailed comparison to the new pump’s mounting dimensions and hydraulic performance. The pump needs to be able to produce similar flow and pressure while being compatible with the existing skid and piping infrastructure. Dimensional verification is fairly straightforward. The following must be measured:
- Housing diameter
- Flange to flange length
- Bolt pattern (quantity, size, and bolt circle diameter)
- Shaft size
- Shaft spline type
- Shaft extension
Verification of hydraulic performance is done by matching the existing pump’s output to the retrofit pump’s output. Power required by the new pump is checked against the motor’s nameplate rating. Thrust generated is checked against the thrust chamber’s bearing capacity. And the performance curve is verified to ensure all possible operating points are covered by the pump within the permissible speed range.
Thrust chamber (HTC / TC) retrofits can be the most complex, but potentially offer the most performance gain. As stated in a previous blog post, cheap thrust chambers are a frequent culprit when investigating poor reliability. HOSS has standardized on a robust, patented high thrust capacity design to achieve maximum HTC longevity. It is possible on most competitor systems to eliminate low-capacity ball bearing thrust chambers by replacing them with the HOSS design (see example pictures). HOSS provides a compatible bolt-on skid mount, along with the required coupling and intake modifications to adapt existing system components to the HOSS thrust chamber system. The following information is typically gathered to prepare for a full HTC retrofit:
- Motor HP rating and frame size
- Various dimensions between the motor shaft and the skid’s first pump support
- Pump barrel manufacturer and nameplate data
- Mechanical seal type, intake pressure, and pumped fluid
- Intake size, class, and material
- Past customers have reported a 4-5X improvement in mean time between failure (MTBF) by transitioning away from short-run life ball bearing thrust chambers on their installed systems.
Motor replacements are the easiest retrofit, assuming that the skid is large enough to accommodate the chosen motor. Motors are typically replaced when increased flow or pressure require more power, or an above-NEMA frame motor fails and a replacement is not immediately available from the original motor manufacturer. The existing motor is removed and the skid’s motor plate is redrilled for the replacement motor.
Even if a horizontal pump provider is capable of the rigorous retrofit engineering process (most are not), they must possess comprehensive manufacturing capabilities to quickly produce equipment for the retrofit. Above all, a successful retrofit also requires trained, experienced field service technicians that will be present at every service visit, from the first-dimensional survey to the final commissioning. Retrofits are undoubtedly complex. However, the promise of improved pumping system performance is worth the effort.