Team 26 Miniature Flow Control Valve

4/24/2023

Manoel Aguirre Lara, Matthew Cordova, Michael Gigoux, Bora Gursel, Anannaya Vij

Project Overview

• The sponsor aims to test chips in a variety of testing environments with differing geometry and a highly variable temperature range: -40°C to 175°C.
• Key Problem: High Temperature Performance & High Cost
• At high temperatures, solenoid coils in the flow valve experience demagnetization.
• High temperatures damage wiring in flow valve.
• Flow valve is well designed, but has a relatively high cost.
• Key Problem: Unpredictable Geometry
• Current valve system is compatible with multiple testing systems because of its combined nature.
• Adaptability is important in reducing cost and ease of replacement.

2

Project Objectives

Primary Objectives:

• Separate the flow valve and its solenoid actuator using an intermediary mechanical linkage by a distance of 1 meter.
• The flow valve functions in an environment ranging from -40°C to 175°C.
• The system response adheres to specific performance criteria.
• 1.5 L/min water flow rate.
• Fully open to closed and vice versa in <1 sec.

Secondary Objectives:

• Minimize cost of flow valve from current cost at $270.
• Reduce usage of machined components in favor of COTS.
• Reduce valve footprint to be half of what the current combined valve & actuator occupies.

3

Full CAD of Current Design

Valve Base

Figure 5: Flow Valve Spring Housing

Interface Requirement for Valve Housing

• Note the interfacing port which must match the valve base�(M8 threading)

Prototyping Concepts (Mechanical Linkage)

• Design criteria: minimize the amount of custom-made parts
• Ideal to have no custom-made parts given secondary design criteria
• “Reduce usage of machined components in favor of COTS”
• All we need to do is assemble the individual Bowden cable parts

Figure 4: Linkage Attachment to Flow Valve

Progress From Previous Week

• Purchased first set of materials to begin assembly & prototyping (Bora)
• Spring not yet purchased b/c overlapping design concerns with actuator and flow mechanism (discussed more in weekly objectives)
• Created rough CAD design for the linkage mechanism that will inform prototyping phase (Michael)
• Spoke with “Carl Stahl Sava Industries” about sampling 25ft of Teflon coated steel cable for our prototyping (Matthew)
• Potential alternative to unlubricated wire for decreasing wear on silicon rubber tubing
• Identified suitable Teflon o-rings for the valve housing to ensure viable seal at working temperatures (Bora)
• Talked to MAE staff about actuators and they recommended stepper motor. Emailed sponsors about it (Manny)

Objectives For Week 4

• Assemble the Bowden Cable for preliminary testing (Matthew and Michael)
• Determine if the unlubricated wire will be an issue for wearing down the silicon tubing and end fittings that will be attached to the wire
• Order springs from Vendor (Bora)
• may order multiple different types of springs for prototyping to avoid having to re-order
• Identify methodology for sizing O-Rings
• Meet with machine center staff about manufacturing valve base prototype from Aluminum (Bora)
• Finalize CAD and CAM designs for the valve base and conceptualize integrating the valve mechanism with the actuator

Objectives For Week 4

• Ask prof. Ian and prof. Steven if they can provide a stepper motor as well about any recommendations regarding where to buy them (Manny)
• Purchase stainless steel (SS) or alternative manufacturing plan for valve body (Anannaya)
• Contact suppliers for SS valve body and gather more manufacturing info (Anannaya)
• Start testing and design on test stand for our prototyped valve (Anannaya)
• Purchase Springs
• ​

Major Purchase Items

• Bowden Cable Components (Ordered and Arrived)
• Wire rope ~$0.80/ft form McMaster-Carr (Purchased)
• PTFE tubing ~$3.55/ft from McMaster-Carr (Purchased)
• Flexible metal conduit ~$3.61/ft from McMaster-Carr (Purchased)
• Variety of end fittings (for prototyping of linkage-actuator and linkage-valve systems, fitting shape and product TBD)
• Valve Housing & Spring
• 1” Diameter Aluminum Round Stock for Prototyping ~$19 from OnlineMetals (Purchased)
• Smalley SSB-0063-S17 Spring ~ $26 for 4 springs from Smalley Springs
• ~28 day lead time!
• Stepper motor

Sponsor Comments

• Comment: It will be necessary to start developing a control system that relies on feedback control to achieve desired flow rates.
• Sponsor will get back to us regarding the current control feedback mechanism
• Could be either a position or flow based control scheme
• Recommend using arduino control combined with a relevant sensor.
• Comment: Could be possible to develop valve housing from a COTF component.
• Bora will do further research.

Risks and Areas of Concern

• With our current wire being unlubricated, there might be more wear between the silicon tubing and the inner steel wire
• Sourcing a “sample” of 25ft of Teflon coated wire from Sava if/when this becomes an issue for cycle lifetime
• Still unsure if Teflon coated wire is able to withstand maximum temperature range for Cohu testing rig
• Product description rates the Teflon coating for up to 400C (max temperature of test rig is ~350F) but supplier email showed uncertainty (will have to email them again to address their concern)
• Valve housing prototyping is a risk area - will work with MAE machine center to address manufacturing concerns
• Sizing O-Rings?
• Converting rotational motion into linear motion

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Gantt Chart

Gantt Chart

Gantt Chart