Tec de Monterrey, 2021

The team embarked on a mission to solve a very real problem for Clínica San Carlos in Orogachi: how to collect and transport potable water from a nearby well efficiently and affordably. Instead of a purely academic exercise, this project was framed as a real-world engineering challenge, with the team acting as consultants delivering a tangible, usable prototype.

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The goal was ambitious yet practical: design and build a dismountable, low-cost hydraulic pump capable of delivering 400 liters of water per day in under 20 minutes. To achieve this, the team followed a structured six-phase plan: task organization, mechanism proposal, mathematical validation, dimensional verification, prototype machining, and finally testing and improvement. A Work Breakdown Structure, Gantt chart, and precedence diagram were created to assign responsibilities, visualize dependencies, and maintain progress control. Stakeholders included not just the client but also EVANS engineers (consultants), professors (supervisors), and the team itself, highlighting a realistic project management approach.

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The team evaluated multiple pump configurations: centrifugal, rotary, and reciprocating, and chose a double-acting reciprocating submersible pump. This choice minimized "dead cycles" in fluid flow, ensuring continuous pumping and meeting the throughput goal.

Three design variants were developed in CAD: small, medium, and large pumps, each with different chamber capacities and geometries. After comparing cost, ease of construction, efficiency, and force transmission angles, the large model was selected as the optimal solution. Its advantages included double the required flow capacity, better mechanical advantage, and minimized angular stress on the connecting rods.

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The design phase was grounded in a full mathematical model. Using Bernoulli’s equation, continuity equations, and the Darcy–Weisbach formula, the team calculated the required head, flow rate, and friction losses for 3 m vertical lift and 1000 m horizontal piping. Additionally, the human power input was modeled, assuming a person could deliver ~50–75 W continuously through a bicycle pedal mechanism. The resulting torque and angular velocity requirements were derived, and the mechanical linkage (biela-manivela) was dimensioned accordingly. The structural integrity was validated through force and moment equilibrium equations and solved as an 8×8 matrix system, later automated in Python for iterative adjustments. The calculated forces were well below the yield strength of chosen materials, confirming that the design would operate safely under expected loads. 

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Material choices balanced strength, cost, and manufacturability:

• Aluminum 6061 for pistons and crank components (lightweight, corrosion-resistant).

• PVC for vacuum chambers and caps (cheap, easily machinable).

• Bronze check valves for reliability.

• Rubber O-rings for sealing and reduced leakage.

• Recycled bicycle parts for the drivetrain (crank, gears, chain).

A cost analysis showed all three variants were within MXN $3,000–4,000, making the large design economically viable.

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The team translated CAD models into detailed 2D technical drawings, then began machining the prototype in the university workshop. Key activities included:

• Cutting and welding the PTR steel frame for structural support.

• Machining threaded rods and cylinder connections on a lathe for precise fits.

• 3D-printing pistons with PC-ABS material for improved durability.

• Modifying donated bicycle parts to integrate with the pump mechanism.

• Iteratively adjusting dimensions to fix misalignments and reduce friction.

By the final day, the pump prototype was fully assembled, painted, and functionally tested. The mechanism worked, but some frictional interference between moving arms and guides limited smooth operation, which the team planned to address in future iterations.

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The project served as a comprehensive exercise in mechanical systems design, requiring not just calculations but also iterative prototyping, hands-on machining, and field-oriented problem-solving. The team gained experience in stakeholder communication, rapid design adjustments, and applying theoretical knowledge to a real-world challenge. Future plans include refining the prototype to reduce friction, validating the hydraulic performance with actual flow tests, and finalizing the piping system for field deployment at the clinic.

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Please find attached below the relevant documents to this project. (Note: most, if not all documents, are in Spanish)