It happens to just about every EASA service center. A machine shows up for repair; it has leads, and there’s a motor, but the machine is a pump. Most often, it’s a close-coupled pump or a submersible pump. If your response is, “We don’t work on those here,” because you’re thinking, “We don’t know anything about repairing pumps,” you may be turning your back on some very profitable work.

Esto sucede en casi todos los centros de servicio de EASA, aparece una máquina para reparación, con cables y un motor, pero es una bomba. A menudo es una bomba sumergible o de acoplamiento cerrado. Si su respuesta es: “Aquí no reparamos estos equipos” y está pensando: “Nosotros no sabemos nada sobre reparación de bombas” puede que le esté dando la espalda a un trabajo muy rentable.

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EASA service centers looking for options for expansion, or to replace evaporating existing electric motor repair markets, have seen pump repair as a good fit. A majority of EASA service centers currently repair roto-dynamic pumps. Pumps are by far the largest category of machines driven by electric motors. If a service center is repairing electric motors, then it is almost certain that some of those motors are driving pumps, and the prospects for pump repair are its existing customers.

Los centros de servicio miembros de EASA que buscan expandirse o que estén interesados en reemplazar los mercados de reparación volátiles existentes, han visto en la reparación de las bombas algo idóneo. Por lo general, la mayoría de los mismos repara bombas roto-dinámicas. Por mucho, las bombas son la categoría más grande de máquinas accionadas por motores eléctricos.

Las bombas de turbina verticales (VTP) son accionadas por motores verticales provistos con grandes rodamientos de empuje que soportan el peso del rotor del motor, el rotor de la bomba y el empuje dinámico hacia abajo, producido por los impulsores cuando levantan el líquido. El peso del rotor del motor y del rotor de la bomba se determinan fácilmente a partir de datos de ingeniería simples. El cálculo del empuje producido por los impulsores cuando interactúan con el líquido en movimiento es mucho más difícil y no siempre el empuje es generado hacia abajo.

En este artículo revisemos brevemente cómo se produce el empuje hacia arriba en las bombas y las disposiciones en los motores VTP diseñados para controlarlo.

Vertical turbine pumps (VTP) are driven by vertical motors with large thrust bearings that support the weight of the motor rotor, the pump rotor and the dynamic down-thrust generated by the pump impellers as they lift the liquid. The weight of the motor rotor and pump rotor are easily determined from simple engineering data. The amount of thrust generated by the impellers as they interact with the moving liquid is much more complicated, and the thrust is not always generated in the downward direction. This article looks at how up-thrust occurs and the provisions to control it.

One of the most common repairs on centrifugal pumps is replacing worn or damaged wear rings. To restore efficient, reliable operation and prevent catastrophic pump failure, it is critical to restore proper clearances between the stationary casing wear ring and the rotating impeller wear ring. Although many pump manufacturers provide clearances and dimensions, some do not. There are plenty of aging pumps around from now-defunct manufacturers for which dimension data is simply not available.

In such cases, the rule of thumb that follows provides some guidance for acceptable running clearances, or the minimum running clearance chart in American Petroleum Institute (API) Standard 610 can be used as a guide.

Submersible pumps may have any of several types of internal sensors or protective devices. These may include temperature sensors, vibration transducers or moisture sensors. The type of temperature and vibration devices are identical to those used in non-submersible style motors, so only the moisture sensors are of special interest regarding submersible pumps. It is important for technicians involved in the repair of submersible pumps to be aware of their presence in any specific pump they may encounter, and understand the manner in which they function to ensure they work properly after repairs are completed.