1	"Group 18" Group 18: Alejandro Castro Sam Leuthold Andrew Borger
2	Overview Problem Statement Application Concept Selection Flow Calculations Concept Designs Force Calculations Material Selection Brief Cost Analysis Failure Mode Analysis Summary
3	Problem Statement Gas compressors are used to transport and store natural gas Current compressor valves are reliable but inefficient in flow A valve with a more direct flow is needed Obtain direct flow with a rotational type valve
4	Application
5	Application
6	Concept Selection
7	Flow Calculations(Time)
8	Flow Calculation(Inlet)
9	Flow Calculation(Exhaust)
10	Design 1: Inner-thread Rotation
11	Design 1: Thread Rotation Fixed outer casing Rotating/translating center plate Splined and threaded center bolt Return spring
12	Design 1: Thread Rotation
13	Concept 1: Valve Operation
14	Design 2: Pitch Rotation
15	Design 2: Pitch Rotation Same basic concept as Design 1 Threaded outside housing plate Simple retaining bolt
16	Design 2: Outer Pitch Rotation
17	Concept Comparison Uniform force distribution Less force on threads Less chance for debris Ease of machining Pins may not be durable Low pitch angle Higher pitch angle Higher chance for debris Bolt difficult for machine Pressure difference across valve face Tighter tolerances Threaded Housing Threaded Bolt
18	Force Calculation (Bottom Dead Center)
19	Force Calculation (Up Stroke)
20	Force Calculation (Valve Open)
21	Material Selection All materials must be resistant to temperatures of up to 350F Translating materials must be wear resistant due to required lifetime (6.3x10⁸cycles) Sliding surfaces must also be low in friction (µ < 0.15) Valve is to be sealed to prevent leakage
22	Translating Material No lubrication Graphite in cast iron creates a natural lubrication Hardness Surface roughness Threaded cast iron insert
23	Gasket Material Perfluoroelastomer (FFKM) Rubber form of PTFE High temperature stability up to 327°C (620°F) Almost universal chemical resistance Outstanding mechanical and chemical properties
24	Cost Analysis Raw cast iron(cylinder): $5 Raw cast iron (plate): $120 Spare parts: $10 Machining (College of Engineering): $0 Total: $135
25	Failure Mode and Effects Analysis Procedure in product development to detect possible failures and score them on severity, occurrence, problem detection
26	Summary Concerns of complete open operation Vary pitch angle Adjust spring constant Alter valve passage geometry Wear and Debris Adjust tolerances Material selection Operation Speed/Spring flutter Avoid resonance
27	References http://www.eng.fsu.edu/~castral http://www.enginebuildermag.com/Article/1171/valve_selection_hot_valve_materials_for_hot_engines.aspx https://supportcentral.ge.com/products/sup_products.asp?prod_id=184232 http://www.machinerylubrication.com/Read/775/reciprocating-compressor http://www.machinerylubrication.com/Read/1348/acid-lubricant-piston-rods http://www.electro-coatings.com/hard-chrome-wear-resistance.php http://www.prepol.com/Perlast.html
28	QUESTIONS