ChemE Car Stopping Mechanism:Spring Pressure Stopping

SystemUCSD 2015-16

Donovan LyJoanne LySean Riley

Shaocheng HuAlan Tam

Cheryl Chan

Spring Pressure Stopping MechanismOur designed stopping mechanism revolves around a chemical reaction which produces gas as a product to create a pressure build up within the reaction tank. This pressure would create a force pushing on a piston which is held by a spring. Once the pressure of the reaction is greater than the force of the spring, the pistol will be propelled towards a button and/or switch linked to the propulsion system that be immediately shut off.

Our system is based off of 3 different variables:❖ Pressure generated

➢ Different chemical reactions, reactants, products, conversion, and yield ❖ Spring Constant (F = ma = kx)

➢ Varying mechanical components change the force needed to push the piston❖ Distance between piston and button and/or switch

➢ With spring constant and reaction fixed, we can vary the distance needed to add additional versatility to our system

Overview: Integration Within the Car

Visualization of Spring Mechanism

1. Diagram of how your system must be integrated within the car. For example, how it is hooked up electrically or mechanically

Types of Chemical ReactionsSince our design is based off of pressure, we chose the following reactions that produce gas as a product for the pressure build up, along with taking into account material pricing and the NFPA safety rating of each reactant and product

❖ Sulfuric Acid + Calcium CarbonateCaCO3 (s) + H2SO4(aq) → CaSO4(aq) + H2O(l) + CO2 (g)

❖ Nitric Acid + Sodium Carbonate2HNO3(aq)+Na2CO3(aq)→2NaNO3(aq)+CO2(g)+H2O(l)

❖ Hydrochloric Acid + Calcium Carbonate2HCl(aq) + CaCO3(s) → CaCl2(aq) + H2CO3(aq) → CaCl2(aq) + CO2(g) + H2O(l)

❖ Acetic Acid + Sodium BicarbonateCH3COOH(aq) + NaHCO3(aq) → NaCH3COO(aq) + H2O(l) + CO2(g)

Sulfuric Acid & Calcium Carbonate ReactionCaCO3 (s) + H2SO4(aq) → CaSO4(aq) + H2O(l) + CO2 (g)

❖ Procedure1. Calcium carbonate is initially in the tank.2. Sulfuric acid is added in by a syringe.3. Optional: Shake tank to speed up the reaction.

❖ Reaction is rapid➢ Saves pressure build-up time.➢ Most likely will not have to shake the tank.

❖ Gas ProducedCO2

❖ Exothermic

Nitric Acid & Sodium Carbonate Reaction2HNO3(aq)+Na2CO3(aq)→2NaNO3(aq)+CO2(g)+H2O(l)

❖ Procedure1. Sodium carbonate is initially in the tank.2. Nitric acid is added in by a syringe.3. Optional: Shake tank to speed up the reaction.

❖ Gas ProducedCO2

❖ Reaction is rapid➢ Saves pressure build-up time.➢ Most likely will not have to shake tank.

Hydrochloric Acid & Calcium Carbonate Reaction2 HCl(aq) + CaCO3(s) → CaCl2(aq) + H2CO3(aq) → CaCl2(aq) + CO2(g) + H2O(l)

❖ Procedure1. Hydrochloric acid is initially in the tank.2. Calcium carbonate is tipped in. 3. Optional: Shake tank to speed up the reaction.

❖ Reaction is rapid➢ Saves pressure build-up time

❖ Gas ProducedCO2

❖ Temperature & VolumeAs temperature increases, the rate of volume of gas produced increases.

❖ at 60℃, 1M HCl: 20sec: ~22mL; 40sec: ~36.5 mL; 1min: ~46.5 mL➢ can control rate of gas produced with temperature

❖ Exothermic

Data from: http://www.123helpme.com/view.asp?id=122747

Acetic Acid & Sodium Bicarbonate ReactionCH3COOH(aq) + NaHCO3(aq) → NaCH3COO(aq) + H2O(l) + CO2(g)

❖ Procedure1. Sodium bicarbonate is initially in the tank.2. Acetic acid is added in by a syringe.3. Shake tank to speed up the reaction.

❖ Gas ProducedCO2

❖ Pressure & TemperatureUse Gassby’s data as a reference.

❖ Pro: Gassby is proof that the reaction is reliable.❖ Con: Pressure build-up time takes too long.❖ Endothermic

➢ poses less of a risk compared to an exothermic reaction

List of Chemicals and CostMaterials NFPA Rating Price Seller

Sodium Nitrite 2,0,1 2 lb for $7.50 Duda Energy

Sulfamic Acid 2,1,0 1lb for $6.50 Amazon

Sulfuric Acid 3,0,2 950 mL for $12.95 Amazon

Calcium Carbonate 0,0,0 1lb for $8 Duda Energy

Acetic Acid 2,2,2 950 mL for $9.50 Walmart

Hydrochloric Acid 3,0,0 500 mL for $6 Amazon

Sodium Bicarbonate 1,0,1 1lb for $8.75 Duda Energy

Nitric Acid 3,0,0 1L for $51.95 Duda Energy

Total: $111.15

NaNO2

CaCO3

Na2CO3

Mechanical ComponentsPneumatic Cylinder / (7/16 in., 0.1 lb, Bore, Single-Acting, Spring Return, Rear Pivot Mount)

Stroke Length (in.) Length (in.) Price Seller

0.5 2.64 $13.50 Automationdirect.com

1.0 3.63 $14.50 Automationdirect.com

1.5 4.57 $15.50 Automationdirect.com

2.0 5.51 $16.50 Automationdirect.com

Mount Style Bracket Nut Total Price Seller

Front Nose $2.50 $1.00 $3.50 Automationdirect.com

Rear Pivot $2.75 - $2.75 Automationdirect.com

Mechanical Components ContinuedAdditional Materials

Products Specification/detail Price Seller

Pressure Gauge $7.00 Automationdirect.com

Polyurethane (PUR) Hose 8 ft Hose $13.00 Automationdirect.com

Hose Clamps (2) $0.98 each Home Depot

Barbed Hose Fittings (2) $1.68 each Grainger.com

Pressure Release Valve $19.53 NRI Industrial

Pushbutton $9.75 SparkFun Electronics

Fittings Cross / Hex Nipple $3.00 / $5.38 Merit Brass / Parker

Possible Containers Gas Cylinder / Lab Reaction Tank

$4.00 / $30.00 Alibaba.com

Total Price of Mechanical Components The price of the additional materials is approximately: $73.23 or $99.23

The total price will vary depending on the Pneumatic Cylinder we purchase and the reaction container.

Additional Information about each product will be provided on a separate document due to limited slide space.

$13.50 Cylinder $14.50 Cylinder $15.50 Cylinder $16.50 Cylinder

+ $73.23 or $99.23 + $73.23 or $99.23 + $73.23 or $99.23 + $73.23 or $99.23

Total: $86.73 - $112.73 Total: $87.73 - $113.73 Total: $88.73 - $114.73 Total: $89.73 - $115.73

Hazard StatementsCaCl2,CaSO4,CaCO3,NaCH3COO,CH3COOH,NaHCO3,Na2CO3: Causes serious eye irritation

CaSO4,HCI,NaNO3: May cause respiratory irritation

HCl,NaHSO4,H2SO4,CH3COOH,HNO3: May be corrosive to metals

HCl,NaHSO4,H2SO4,HNO3,NaNO3: Causes severe skin burns and eye damage

N2,CO2: Risk of explosion if heated under confinement

NaNO2: Toxic if swallowed

NaNO2,NaNO3: Very toxic to aquatic life

NaNO3: Harmful if swallowed

NaNO3: Suspected of causing genetic defects and cancer According to ChemWatch Review SDS

Safety Precautions Prevention❖ Do not breathe dust/fume/gas/mist/vapours/spray

❖ Wear protective gloves/protective clothing/ eye protection/face protection

❖ Keep chemicals only in original container

❖ Wash hands and equipments thoroughly after handling

❖ Do not eat, drink or smoke when using chemicals

❖ Avoid release to the environment

❖ For hydrochloric acid, use only outdoors or in a well-ventilated area

❖ Chemicals are disposed properly based on their chemical properties and laboratory requirements

❖ Pressure gauge is used to monitor the pressure inside system

❖ Appropriately sized and set relief valve is used to prevent system from explosion

Safety Precautions Response❖ If in eyes: Rinse cautiously with water for several times

❖ If eye irritation persists: get medical advice/attention

❖ If inhaled: Remove victim to fresh air and rest in a position comfortable for breathing

❖ If swallowed: Rinse mouth. Do not induce vomiting

❖ If on skin: Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower

❖ Absorb spillage to prevent material damage

❖ Call a POISON CENTER or doctor/physician

Concerned regulation❖ Maximum operating pressure should be no greater 90% of the MAWP

❖ Pressure greater than 500 psi is not allowed

❖ A pressure gauge that reads from 0 psig to 2 times the maximum operating pressure

❖ All components must be certified to operate at a pressure greater than the maximum operating

pressure

❖ No PVC, cPVC, PETE or PET vessels or piping used for pressurized gases are allowed.

❖ Appropriately sized relief valve is required for pressurized gas

❖ All chemicals are injected into the reactor vessels with syringes at the start of the line. ❖ Wash contaminated clothing before reuse

Proposed Research PlanNov. 7 – Nov. 12: Research❖ Division of work split between each team member for independent research

➢ Safety procedures, rules, and regulations➢ Budget➢ Mechanical / electrical components➢ Chemical reactions➢ Diagram / animation for our design

End of Nov. – After system presentation: Trial and Error❖ Purchase material to start testing of design

➢ Reaction tank ➢ Piston / spring ➢ Button / circuit switch➢ Pressure release valve, gauge➢ Tubing, chassis shell, etc.

Research Plan Cont.Dec – Jan: Test different chemical reactions for specific pressure build up❖ Vary concentrations of reactants❖ Yield and conversion of different products

Jan - Feb: Test different springs for different spring constants❖ Determine amount of force necessary to move piston to button/switch

Test various distance lengths for pistol to travel in order to push button/switch❖ Spring constant is fixed, cannot vary as much, but can vary the distance between pistol and button❖ After deciding on a specific spring, can determine length needed for given reaction

Feb – March: Start building vessel under competition regulations, and fit design into chassis❖ Test chassis stopping system with various other propulsion mechanisms for data

➢ Be able to be used with variety of propulsion mechanisms➢ Account for new variables (ie. weight, momentum, friction, etc.)

Potential Issues and TroubleshootingPotential Issues to Consider:

❖ Pressure build up can be really high and unsafe (>> 1psig); need pressure gauges to monitor the pressure and a pressure regulator

❖ A steel container is required to withstand the pressure from gas build up; most glass containers can only withstand less than 25psig

❖ Include a safety release valve in case the pressure goes 110% of the operating pressure in case the regulator or piston fails

❖ Car will not go to a complete stop after switch is turned off -- we would have to work with the propulsion team to determine the additional distance that the car will cover after the switch is turned off

Additional DetailsRecycle of data and equipment

❖ Gassby car used a similar design for propulsion system, which we can recycle old data and equipment that is suitable for our design that will save us effort, time, and money➢ Reactant amount and concentration➢ Generated pressure➢ Reaction tank, tubing, hardware, etc.

Versatility

❖ Our design system can be applied to a variety of different propulsion systems, not limited to only a pressure system vessel➢ button / switch can shut off circuits, turn off motors, cut off electrical currents, etc.

Thank You for Your TimeQuestions?

ReferencesPneumatic Cylinders: Automationdirect.com