Group 13 - Kerosene Heater

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Executive Summary

Group 13 dissected a kerosene torpedo heater to apply reverse engineering processes. For the dissection we recorded, in detail, both the disassembly and reassembly processes, in a stepwise fashion including detailed pictures of parts and assemblies. When the heater was dissected, we analyzed the major components to see how manufactured and what materials were used. We discussed the engineering choices for the parts, analyzing the advantages and disadvantages of the parts design and construction methods. Several recommendations were also made, biased on our testing and dissection of the heater, to improve the heaters design.


The heater dissected by group 13 is a portable unit that burns kerosene and is intended for use in shops or other work environments. It includes features such as a thermostat and safety checks.

Communications Manager: Mariano Hernandez. As the Communications Manager, Mariano will be the point of contact between group 13 and our T.A.'s and Professor. He will be responsible for alerting group members to all notices and changes relating to the project. To contact Mariano use his e-mail address which is

Lead Wiki Developer: Jonathan Gambacorta. As the Lead Wiki Developer, Jonathan will be responsible for the creation and formatting of our wiki page. This will include submissions to the page and overall look and layout of the page. AS the wiki developer Jonathan will have to gather all information from group members and complies it to put on the wiki page.

Dissection Leader: James Glennon. As the Dissection Leader, James will always know the current progress of the dissection and the steps needed to dissect the heater. James will also have to keep track of parts and tools used in this process. James will also be in charge of the reassembly.

Lead CAD Designer: Benjamin Deuell. As the Design Specialist, Benjamin will use Autodesk Inventor to create solid models of our heater and its components. The lead CAD Designer will also take the solid models that he created and is responsible for getting them on the wiki.

Lead Data Gathering and Information Specialist: Karan Kapoor. As the Lead Data Gathering and Informations Specialist, Karan will record data throughout the dissection. He will be a multi-media specialist by taking pictures, video and notes that will log the disassembly and provide to be crucial during reassembly.

Work Proposal (link)

Initial Product Assessment

Initial Disassembly Process

Step Part Tools Notes
1 Outer Shell and Frame Phillips Head Set Can be easily removed first since its located on the exterior.
2 Compressor Phillips Screwdrivers and wrench The compressor will be easily removed once the outer shell is off.
3 Blower Screwdriver and Adjustable Wrench Since the blower is next to the compressor, after the compressor is removed the blower should come out easily
4 Burner Phillips Screwdriver, Adjustable Wrench, Wire Cutters Removing the burner may be complicated by wiring. We also dont know how the burner is ignited since we can not see the part
5 Electrical Components and Ignition Phillips Screwdriver, Wire Cutters With all other components removed and just the electrical components will remain. We will have to somehow tag the wires so that we know where they go when we re-assemble.

  • The intended use of this product is to heat a room or a space outdoors. The product is just a simple heater and is really only used for warmth.
    • This product is of industrial size but it is not limited to professional use. If you have a large enough space you can use this heater effectively.
    • The product has two functions one is simply turning on the heater and letting it heat the area intended to be heated. The other is to set it on a temperature recognition and it will not let the temperature fall below this.

  • From initial inspections the heat is produced from burning kerosene and a fan that blows the hot air. There is also a compressor in the heater which would be used to draw the kerosene from the tank towards the burner by siphoning it up.
    • The heater uses electrical, mechanical, potential and thermal energies
    • The kerosene heater has an AC power cord on in and must be plugged in to work. There is electrical energy that is used to start the heater and power the compressor and fan. The electrical energy is converted to mechanical energy by the fan and compressor. The compressor draws up kerosene which has a potential energy, this energy is released into thermal energy when the kerosene comes close enough to the burner to ignite it.

  • The heater appears to work well, it ignites easily and the thermostat features are functioning. The heat output also appears to be sufficient however the testing was not preformed at the cold temperatures the heater would likely be used.
  • Overall the concept of heater is not very complex; it is basically a system containing a controlled flame in a tube where air and fuel are fed. The heater is just a well controlled fire.
    • There are five main components in the heater the main body comprised of the tank and cart, the electronics, the compressor, the blower and the burner.
    • The compressor, the burner, and the automatic controls are all complex components when examined individually. All of these components required careful engineering and despite the simple task they perform they are complex internally. The blower and the frame on the other hand are rather simple components that required significantly less engineering to design.

  • The kerosene heater likely made of many different materials; however there are only a few materials in significant quantity. Metals such as copper and steel as well as plastics and rubber are all used in the design.
    • The fuel tank, safety shroud, and electrical housing are made of sheet steel. The electrical housing also has a few plastic components for the controls and a power cord made of copper and rubber. There is a safety grill on the intake end made with steel wire. The heaters fuel tank is built into a cart with steel tubing and rubber wheels with steel hubs.
    • Inside of the heater there is likely a burner, a blower and a burner. The burner is probably built from steel sheet. The blower is likely made from steel with copper windings in the motor. The electrical controls are most likely built from copper and plastics.

  • Satisfaction with this product would depend upon the size of the room. Kerosene heaters aren’t very effective when it comes to large spaces and rooms, but they do an excellent job when used in small spaces.
    • Our product is really comfortable to use, it is very user friendly and can be conveniently controlled by its built in thermostat.
    • In the case of our product, comfort and ease of use go hand in hand. The fact that it is comfortable to use makes it easy to use as well because one really doesn’t have to do anything once the heater is on because it goes on to do what it’s supposed to do. ‘ What it does is what it is’, this statement holds true for this product as it does what it’s supposed to do with ease and very requires little or no adjustments.
    • The heater requires regular fueling and its air filters need to be cleaned on occasion. Fueling the heater can be done with ease but cleaning of the air filter would be more difficult considering there is no direct access to it. It would require some disassembly of the product.
  • There are three manufactures that provide similar alternatives to our product. They are Mr. Heater, Master and DURAHEAT. Each of these manufactures provided a product which is comparable to ours. Our product boasts 210,000 BTU/hr output, a fuel consumption of 1.6 gal/hr and a fuel tank capacity of 13.0 gallons. It has a power requirement of 120v or 60Hz, can operate with No.1 kerosene, diesel or fuel oil and has a max outlet air temperature of 1,165° F.
    • The differences in cost between the DURAHEAT, Master and Mr. Heater products are quite competitive; Master’s product sells for $398.00 while Mr. Heater’s Product sells for $399.99. This gives a cost difference of $1.99. DURAHEAT is a little pricier with their product selling for $449.99. This gives a cost difference of $50.00 between Mr. Heater’s product and a $51.99 cost difference between Master’s product. Considering these products I would estimate that our product would sell around the $399.99 mark, considering it is most like Mr. Heater’s product.
    • . The advantages our product has over its completion is a 10,00 BTU/hr advantage over Master’s product and the wheel and handle kit is sold separately for DURAHEAT’s product. Every other aspect is matched or beaten by competitors.
    • The disadvantages our product has are fuel consumption, fuel tank size and max outlet air temperature. Our product consumes 1.6 gal/hr while DURAHEAT and Master’s consume 1.3 gal/hr and 1.4 gal/hr respectively. Our products fuel tank size is 13.0 gal while Master and Mr. Heater both have a 13.5 gal tank. Lastly our products max outlet air temperature is 1,165° F while Mr. Heater’s is a much larger 1,450° F.

Product Disection

Difficulty Scale

Our difficulty scale ranges from 1 to 5. 1 is very easy, parts can be easily accessed. 3 would be slightly difficult, access to parts may be limited or they may be hard to minuver. 5 is very difficult, it may require several tries and very good dexterity.

  • A 5/16" nut driver can be substituted for #2 Phillips in some cases

Outer Disassembly

Step Part Name Disassembly Procedure Tools Picture Difficulty Fastener Type
1 Top Outer Shroud 6 Screws removed from top shroud (3 on each side) and shroud lifted off #2 Phillips* Media:Topschroud.jpg 1 F-1
2 Metal Guard Pulled off metal guard with hands Hands Media:Metalguard.jpg 1
3 Thermostat cover Removed 4 screws and unpulgged 2 spade terminals from Power switch #2 Phillips* and Hands Media:thermostatcover.jpg 2 F-1
4 Circuit Board Disconnect 3 electrical connections, 4 spade terminals from circuit board. Unscrew 2 screws from top of circuit board. Remove Circuit Board #2 Phillips and Hands Media:ECB.jpg 2 F-2
5 Ground Wire Unscrewed green ground wire #2 Phillips 1 F-3
6 Zip-tie and Wires Cut zip-tie that groups wires behind the thermostat cover Knife and Hands 1
7 Black and White Power Cords Disconnected Power cords by pinching clip on cord side of connector Hands 1
8 Rear outlet Panel Removed 4 screws and removed rear outlet panel #2 Phillips* and Hands Media:rearpanel.jpg 1 F-1
9 Ground wires from rear outlet Unscrewed ground wires from rear outlet #2 Phillips and Hands 1 F-3
10 Compressor Removal Removed 2 screws from each side (4 Total) then disconnect the air hose. Remove compressor by lifting up. #2 Phillips* and Hands Media:compressor.jpg 2 F-1
11 Burner connections unplug 2 electrical connections with hands from igniter, disconnect fuel and air hoses Hands Media:burnerconnects.jpg 1
12 Burner Removal Removed 4 screws from bottom of shroud connecting burner to shroud. Lift burner aside #2 Phillips* and Hands Media:burner.jpg 1 F-1
13 Igniter Transformer Removed Transformer for igniter by pulling, all cables were free Hands Media:transformer.jpg 1
14 Hose Removed hoses that connected compressor to burner Hands 1
15 Temperature Sensor Bracket Removed 2 screws from bottom bracket that was mounting the temperature sensor to the shroud #2 Phillips* and Hands 1 F-1
16 Temperature Sensor Pulled out temperature sensor Hands Media:temperaturesensor.jpg 1
18 Bottom Shroud Removed 6 screws from bottom of shroud (3 in front and 3 in the middle) mounting bottom shroud to frame #2 Phillips* and Hands Media:bottomshroud.jpg 1 F-1
19 Gas Cap Unhooked chain connecting gas cap to frame Hands Media:gascap.jpg 1

Compressor Dissassembly

Step Part Name Disassembly Procedure Tools Picture Difficulty Fastener Type
1 Fan Blade Loosen screw holding fan blade to compressor 1/8", pull off fan blade 3mm allen wrench and Hands Media:fanblade.jpg 4 F-4
2 Pressure Gauge Unscrew gauge from back of compressor Hands Media:pressuregauge.jpg 1
3 Plastic Filter Removed 4 screws from Plastic Filter #2 Phillips* and Hands Media:plasticfilter.jpg 1 F-5
4 Compressor Cover Plate Remove 2 gold screws and 4 silver screws from cover plate and pull off cover plate #2 Phillips* Hands Media:compressorcover.jpg 2 4x F-5, 2x F-6
5 Compressor Fins Removed 4 compressor fins by sliding them out of holder Hands 1
6 Compressor Housing Unscrew 2 screws and pull apart #2 Phillips and Hands Media:compressorhousing.jpg 1 F-7
7 Compressor Core Pulled compressor core off shaft Hands Media:compressorcore.jpg 1
8 Capacitor Removed capacitor from clip and pulled back rubber cap. Disconnected 2 spade terminals from capacitor. Hands Media:motorcapacitor.jpg 2
9 Capacitor Bracket Unscrew 2 screws holding bracket to compressor. pull off bracket #2 Phillips* Hands Media:capacitorbracket.jpg 1 F-1
10 Motor Bracket Unscrewed 2 nuts from bottom of compressor assembly and pull off bracket 10 mm Wrench or socket Media:Motormountingbracket.jpg 2 F-8
11 Motor Cover Unscrewed 4 phillips head screws from sides of motor and pull off cover #2 Phillips and hands Media:motorcover.jpg 2 F-9
11 Copper Windings Lift windings off the core Hands 1
12 Core Remove plastic spline from back of shaft and pull out core Hands 1
13 Back Cover Remove Plastic insulator disk and wave spring from inside of back cover Hands 1

Burner Chamber Dissassembly

Step Part Name Disassembly Procedure Tools Picture Difficulty Fastener Type
1 Safety Shroud Use drill to remove 6 "standard" screws off of safety shroud, lift the shroud off of the combustion chamber and set the safety shroud aside #2 Phillips* and Hands Media:safetyshroud.jpg 1 F-1
2 Air deflector Blades remove 4 screws holding the "blades" and fuel injector and ignitor #2 Phillips* and Hands Media:airblades.jpg 1 F-1
3 ignitor unscrew ignitor from blades. set aside ignitor and screw with washers #2 Phillips* and Hands Media:ingitor.jpg 1 F-10
4 fuel injector nozzle remove fuel injector nozzle from fuel injector body and blades 5/8" and Pliers and Hands Media:fuelinjectornozzle.jpg 1
5 fuel injector body remove snap ring connecting fuel injector body to blades, pull out fuel injector body snap ring pliers and Hands Media:fuelinjectorbody.jpg 1
6 light Sensor and Bracket Locate the black light sensor and is bracket on the combustion chamber, Pull out the light sensor and unscrew the 2 black screws holding the light sensor bracket on. #2 Phillips and Hands Media:lightsensor.jpg 1 F-11
7 Blade Mounting Bracket Remove 2 Smaller screws holding mounting bracket to combustion chamber #2 Phillips and Hands Media:bladebracket.jpg 1 F-12

Nozzle disassembly

Step Procedure Tools(if needed) Difficulty
1 Unscrew both hose barbs from the housing 10 mm wrench 1
2 Unscrew the nozzle from the front of the housing 21mm and 16mm wrenches 1
3 Unscrew the core from the nozzle on using pliers and a 16mm wrench Pliers, 16mm wrench 1

4 Slide the washers, spring, and rubber seal off the nozzle core 1

Product Documentation and Analysis

The purpose of Gate 3 is to analyze the design decisions made during the engineering design process

Component Summary

Complexity Scale from 0(Block of raw material) - 5(Engine block)

  • The parts discussed for the component summary represent a distributed sample of the parts. We attempted to choose parts that represented the different materials and manufacturing process used in the heater as well as those important to its function. Due to the large number of parts we could not effectively discuss them all so instead a smaller quantity was discussed in greater detail.
  • Compressor Housing
    • Quantity : 1
    • The compressor housing was constructed of hardened steel. This was chosen due to steels strength and high hardness. The steel has forces acting at the screw holes on each side. The forces are coming from the compressor spinning. Another advantage to steel is that it worked perfectly with the machining needed for this part. Since the housing was round it needed to be turned. You can tell by the high tolerance and the high finish it was also ground and polished. The compressor housing is fitted perfectly with the compressor core, this allows heat transfer from the core to the housing. The housing has holes machined into it that increase the rate of heat dispersion. This part is purely functional since it is inside the compressor and no one will see it. The compressor housing has a complexity of 3.
  • Compressor Cover Plate
    • Quantity : 1
    • Aluminum was selected for this component because it is easier to work with than steel. Plastic cannot be used because the part creates a moving seal in the compressor, and plastic would not withstand this wear. This plate is pressed against the compressor by six screws each of which would likely apply a couple hundred pounds of clamping force. The plate must also hold back air pressures around ten psi. This part is made of aluminum which is easy to machine and cast due to its softness and low melting point. However it cannot be ground so high surface finishes must be achieved during machining. The shape of this part has large amounts of material removed from the center so if it were milled it would require long cycle times making the production slow and expensive. Die casing was used to create a part with high tolerances on a large scale with short production times. The casting included most of the features, such as holes and slots, leaving only a few operations to finish the part. The part was turned on a lathe to create a very smooth surface finish on the sealing surface. It was turned and not milled despite the odd shape so that imperfections left my the tool would be in a circular shape and the internal components of the compressor, which are spinning, would move in the direction as the tooling marks reducing wear. Several holes were then taped by a mill of live tooling on the lathe. Any flashing left from the casting process was removed by a sander. The plate contains many rounded edges to aid in the molding process. The overall shape is circular in the middle so it mates with the compressor unit with tabs on each side to accommodate filters and air ports. The component is mainly designed to be functional, as all choices seem to be made with function or manufacturing in mind. The component is fairly complex containing many features which gives it a complexity of 3.
  • Nozzle and Housing
    • Quantity :1
    • The component is made of brass so that it is easy to machine and can have precise features. The forces applied are from the spring, around 25 pounds; the pressure of the air, around 10 psi; and the forces caused by installing the hose barbs. The brass can be easily and quickly machined on a lathe. The features cut into the part are all circular so they can all be done on a lathe. The parts were made of hex stock so wrenches could be used to thread them together. The housing has several stepped diameters inside so when the internal parts are installed there will be a sealing surface, separating passages for air and fuel. There is also a grove at one end of the housing so an external snap ring can be used to install the assembly. The nozzle is tapered to direct the fuel and air to a mixing point where the jet is located. The corners of the hex on the nozzle are also machined off so it will fit through a mounting hole. The design is functional; all of the design features have a purpose in the parts function. The component is relatively simple has a complexity of 2.
  • Hose Barbs
    • Quantity : 2
    • These parts are made of steel to so they would not brake or strip if over tightened. The largest force on this part would be around fifty inch pounds applied when tightening the fitting. There would also be pressures around 10psi inside the fitting. Steel cannot be effectively cast in this shape and size so all processes must be done by machining. The shape is very circular so all the machining was done on a lathe. The hose end has circular barbs to securely hold on a flexible hose. The threaded end is a 1/8 NPT so its tapered design will create a seal without any sealant. The part was made out of 10mm hex stock so a standard wrench could be used to install the fitting. One of these fittings was modified by shortening the threaded part to allow clearance for the inner parts on the assembly. The design is functional; all of the design features have a purpose in the parts function. The component is relatively simple and has a complexity of 1
  • Jet
    • Quantity :1
    • The jet is made of steel so that the small features will not be crushed or distorted by the forces of assembly. The part is squeezed by two parts threaded together applying several hundred pounds of force. The steel makes the jet difficult to machine due to its hardness and the small size of the part, so the fine slots are likely ground into the part. The overall shape is circular so it was first turned on a lathe. The slots are angled to twist the fuel as it passes through helping create a flame that will jet outward. The hole in the middle is very small so that there will be a pressure drop creating a venture effect drawing the fuel out of the tank. The design is very functional; all of the design features have a purpose and their design has a large impact on the entire heaters function. The jet has a complexity of 3.
  • Hose
    • Quantity :2
    • The function of the hose is to connect the fuel in the gas tank to the fuel filter. The compressor creates suction and sucks up the fuel from the gas tank into the fuel filter where it is filtered of any debris which could cause damage to the compressor/ motor unit. The material of the hose seems to be some sort of synthetic rubber. The shape of the hose does not affect the manufacturing process but the material choice does. Natural rubber does not follow the same manufacturing process as synthetic. The manufacturing process for synthetic rubber is done by combining butadiene, a by-product of petroleum refining, and styrene which is captured either in the coking process or as a petroleum refining by-product. When these two gases are mixed with soapsuds in a reactor raw synthetic rubber is the result. The raw rubber then sent through a process where it is washed and dried. After that process the rubber is ready to be shipped. Synthetic rubber was chosen because of its elasticity and toughness. The hose connects the fuel tank to the fuel filter, in order to do this it must take several turns. This calls for a material which is flexible, it also must be able to withstand constant contact with kerosene and diesel fuel. This is the reason the manufacturer chose synthetic rubber over natural rubber. Natural rubber breaks down much faster than synthetic, synthetic rubber is also able to withstand constant contact with chemicals and moisture much longer than natural. Due to its ability to last longer it requires less maintenance over time. The only force the hose experiences is the force of the suction the compressor creates. The hose is completely functional and has no cosmetic value because it not seen on the exterior of the heater. The hose itself is quite simple it is seventeen inches in length, one centimeter in outer diameter and a six millimeter inner diameter which gives it a complexity .5.
  • Fan Blade
    • Quantity :1
    • The Function of the fan blade is to create air flow through the burner where that air is heated up and then blown out the end of the heater. The compressor/motor unit spines the fan blade at a high rpm so the material chosen must be able to withstand the torque force the fan blade receives. The material of the fan blade is galvanized stamped steel. This was proven by taking a magnet to the blade, the magnet was attracted therefore we know its steel. Steel was chosen for this application because it has the highest strength to weight ratio of any material, the torque force applied to the fan means the material must have great strength. Galvanized steel was chosen over other types of protective coatings because galvanized steel has the lowest cost compared to other coatings such as painting. Galvanized steel also requires less maintenance and a full protective coating can be applied in minutes. This makes it the fastest most cost efficient material to use for its application. Stamped steel is manufactured by applying extreme pressure to a blank piece of steel which form the steel to a desired shape. The shape of the fan blade is five blades each with curves in them, this was chosen by the manufacturer to maximize the air flow created. Four blades or three would have been less effective in producing the desired air flow. For the most part the material choice of galvanized steel does not affect the manufacturing process considering that aluminum, brass, cold rolled steel, copper, stainless steel and hot rolled steel can all be stamped. However the shape of the fan blade does affect the manufacturing process. A specially made form or die must be made which gives the steel its desired shape. So if a different shaped fan blade was desired a different die would have to be made. Stamping was chosen for this process because is cost effective, fast and precise enough for the application. Stamping also allows many parts to be made in a short time. The fan blade is completely functional and has no cosmetic value because cannot be seen from the exterior. The fan blade itself is fairly simple and has a complexity of 2 because it is one stamped piece, it does however have to have a high finish to maximize the air flow it can create. This can be seen by looking at the amount of light the steel reflects.
  • Metal Grate
    • Quantity :1
    • Steel was chosen for this part since it is stiff, easy to bend and it is cheap. Typically it is not subjected to any forces however someone could be pushing on it with a force probably not exceeding 30 lbs. Steel is ductile so it can be bent into shape and welded. The shape is a spiral so steel was chosen so it can easily be bent. Welding was used to attach the wires together without adding more components and it was bent into the spiral shape. The grate is circular so that it fits into the end of the tube and the spirals are used so 1 piece of steel wire can cover the entire hole. The steel wire was given a painted finish, this prevents rusting and a cosmetic appearance. This part is both functional and cosmetic because it keeps small things out of the heater but can be seen so it is given a painted finish. The part has a complexity of 2.
  • Graphite Compressor Hub and Blades
    • Quantity: Compressor Hub :1 Blades:4
    • This component was made from a round piece of graphite. The slots for the blades were milled for high precision. The hole in the middle was drilled and counter bored then punched out with a broach. The top and bottom surfaces were polished to a high finish. Graphite was used so it could create a moving seal with low friction. Any imperfections will take care of themselves due to graphite’s nature to wear with friction allowing extremely tight tolerances. The compressor creates around 10 Psi of air pressure. The hub spins within the compressor at 1300 RPM however the component is very light causing the centrifugal forces to be small. Graphite is soft so it will be easy to machine. However the graphite can chip if not careful. The material was chosen not due to machining but so the compressor can have a seal and be light weight. The internal slots required broaching because that is the only tool that would be able to work inside of the part. A mill was used on the other processes because it allowed all of the other processes to be done in one step. The sides were polished so that it would have a high finish. The compressor hub is circular to allow it to spin inside the compressor. This part is completely functional since it is inside the compressor and no one can see it when it is running. The graphite compressor hub and blades have a complexity of 3.
  • External Shroud
    • Quantity: 2
    • The shroud was made of steel so the shroud would be durable, heat resistant and strong. Steel can also be machined easily and is cheap. Any forces being applied to the shroud would come from someone or something pushing or putting a force on it, but normally the force acting on it is zero. Steel can be easily stamped and bent into the shape needed. The shroud is curved so it needed to be rolled. It was stamped because it is the fastest way to cut the sheet steel. The shrouds shape was half circles, this was so the 2 halves will fit together into a circle so the fan rotating inside covers the entire tube. This part is both functional and cosmetic, the cover is painted and has logos on it but also protects you from moving internal components. The part has a complexity of 1 due to its simple shape.
  • Handle
    • Quantity: 2
    • The handle was made of structural steel tubing. The tubing is stiff so it won't bend when you go to move the heater. The handle is used to lift the heater which is around 30 lbs. Since the steel is ductile it can be bent into the desired shape the steel had to be painted so that it would not rust. Because the handle is a tube, a typical tube bender could be used to give the handle its desired shape. The tubing was used so it could be easily grabbed without any sharp sides. This part is both functional since it is used to move the heater and cosmetic since it is painted black to match the gas tank. The part has a complexity of 1.
  • Gas Tank
    • Quantity 1
    • Sheet steel was selected because of its durabliltiy and strength. The forces applied are the the weight of the components which sit on top which weight approximately 15 pounds. Steel was chosen so it could be stamped and welded together. The shape affects the manufacturing process because the nature of the tank requires that the tank be assembled with two pieces and welded together. The manufacturing process of stamping was choosen to create the pan shaped halves and to make holes for access points. The tank was welded together to seal the two halves and painted to prevent rust. The tank is rectangular shaped to optimize volume while comfortably fitting under the burner. The gas tank is functional in that its shape was designed to optimize the volume but it is also cosmetic in that it is visible from the outside and is painted to match the rest of the heater. The gas tank has a complexity of 1.5.
  • Brass Nozzle Core
    • Quantity 1
    • Brass was selected from this component for its ease of machining and high tolerances that can be achieved on small components. The core experiences a force from a spring of approximately 25 pounds, the other end of the core compresses the jet with a couple hundred pounds of force. The material choice of brass affected the manufacturing process by making it easier to machine. The shape of the core is mostly round so much of the machining was done on a lathe but there are some slots which required the use of a mill or live tooling. The manufacturing process of turning was chosen because its round so the spring and seal can fit over it, the seal requires a high finish which is why a lathe was used to make the core. A mill was necessary to create the slots so that fuel could bypass the threads. There is a hole in the middle of the core to allow the airflow down the center. The component is functional because all features are involved in its operation. The core has a complexity of 2.

Design Revisions

  • One component of our product which needs revision is the relationship between the upper shroud and fan blade. When first testing our product we discovered that the upper shroud had a small dent in it, we discovered this because when we turned the heater on the fan blade began hitting the upper shroud. We quickly turned the heater off and inspected the shroud and found the dent, we then popped the dent out and tested just how easily a dent could be put it the shroud. We found it was quite easy to dent the shroud by using just our bear hands. Considering this product it meant to be used in commercial environments such as construction sites, it is very possible and likely that something such as a hammer or debris can fall and hit the shroud. Because it’s used in a work environment no one will be closely watching the heater as we were, the fan blade hitting the shroud would probably go unnoticed until further damaged is done to the shroud and fan blade which could decrease power output or completely prevent the heater from functioning. This leaves the customer dissatisfied with the product and unlikely to return for other purchases. We propose that the shroud be reinforced in the location of the fan or simply be made with a thicker stronger material. This revision would greatly improve the heaters reliability and decrease the maintenance needed.
  • When this heater turns on there is no warning. Because the fan and compressor are connected to the same motor the fan cannot provide the warning that the heater is about to start. The heater just kicks on and starts burning almost immediately. There is little time to move out of the way so for less able bodied people a warning mechanism might be necessary to move out of the way before getting burned. A possible fix for the lack of warning would be a buzzer and delay before the motor starts. This could be added to the electronic control board already present with little extra cost. The noise would also not be to mush of an annoyance because the heater is already quite noisy.
  • When we went to test our heater we found that the tank was filled with quik-dry to absorb the excess diesel fuel. This was when we noticed the problem that the fuel tanks drain was not at the lowest part of the tank. It took almost a whole day to get the quik-dry out of the tank due to this. By moving the drain to the lower ring of the tank it would allow all of the fuel in the tank to get out. This would cause you to be able to get all of the fuel out so there would be no residue in the tank. This would decrease the maintenance needed on the tank and would also increase its functionality. Since it is such a simple change it would not affect the pricing of the heater nor would it change how the tank would be machined.

Engineering Analysis

Engineering analysis would be used to design and construct a component before manufacturing the component. Engineering analysis would be used to analyze how fluids would flow through the nozzle and what pressures and dimensions for the part are necessary for it to operate properly.

Problem statement: If there was an obstruction in the compressor system, or a leak that caused the airflow to decrease what effect would it wave on the heat output of the system.

Fig. 2

Assumptions: The failure causes the pressure after the nozzle (P2) to increase by .01 psi Air density change is not significant Heat output is proportional to fuel use Gauge pressure is 8.5 psi Diameter of inlets is .25” Air outlet diameter is .015” Air density is.07647 lbm Atmosphere pressure is 14.6959488 psi Fuel outlet is .015” by .03” in six places Kerosene has a density of 1.572 lbm Heater normally consumes 1.6 gal/hr of fuel Gravity = 32.174 ft/s2 Normal BTU output is 210k

Governing equations: 0= (P_2-P_1)/ρ+(V_2^2-V_1^2)/2 Q=V_1 A_1=V_2 A_2 A_circle=πr^2 A_rectangle=bh


Calculations: new BTU output=210,000((.0733)/(.1027))=149,883 BTU

Solution check: This answer seems probable because when the pressure P2 increases there is less of a pressure difference to draw air into the system.

Discussion: The assumption that P2 increases by .01 could be caused by a decrease in air flow while its magnitude is not associated to a specific airflow in this problem it is a reasonable value. It is assumed that air density remains constant because the pressure change is relatively small and therefore it would not vary significantly throughout the problem. It is assumed that the heat output is proportional to the fuel because the heat comes from chemical energy stored in the fuel and that energy is proportional to mass. All other assumed values are given, measured or chosen to be in the middle of an acceptable range. The velocity is assumed to be constant across the openings because average values are used, however actual velocities are higher in the middle and lower toward the sides.

Solid Model Assembly

The nozzle assembly was chosen for solid model because it is an integral part to the heaters function.


Fig. 6

Cross Section

Fig. 7


Fig. 8

Product Reassembly

Our product runs the same as before disassembly due to our detailed disassembly instructions. We were able to follow our disassembly instructions backwards using the same tools and reassemble the heater with no problems. An additional recommendation our group would make is the addition of a retractable longer power cord. The current power cord requires that an extension cord be used to run the heater. Also we recommend moving the wheels of the heater to the opposite side so that the heater can be moved without standing directly in front of the burner. Lastly we recommend decreasing the distance between the wires of the wire guard at the end of the burner so that it is not possible to fit fingers through.

Difficulty Scale

Our difficulty scale ranges from 1 to 5. 1 is very easy, parts can be easily accessed. 3 would be slightly difficult, access to parts may be limited or they may be hard to minuver. 5 is very difficult, it may require several tries and very good dexterity.

Nozzle Assembly

Step Procedure Tools(if needed) Difficulty
1 Slide the washer, spring, washer and rubber seal on the long end of the nozzle core in that order. 1
2 Place the jet on the other end of the core and screw the nozzle on using pliers and a 16mm wrench Pliers, 16mm wrench 1
3 Screw the nozzle into the housing using a 16 mm wrench and a 21mm wrench 21mm and 16mm wrenches 1
4 Screw both hose barbs into the housing with the shorter one towards the front 10 mm wrench 1


Step Procedure Tools(if needed) Fasteners Difficulty
1 Start with stator blade 1
2 Put ignitor mounting bracket on center of stator blade, with bracket facing square opening on blades 1
3 Slide nozzle assembly through hole in ignitor mounting bracket fasten with snap ring over nozzle Snap Ring pliers 2
4 Place gold spacer then red washer on igniton fastener F-10 1
5 Attach the ignitor to the mounting bracket using this fastener #2 Phillips F-10 1
6 Put ignitor mounting bracket on center of stator blade, with bracket facing square opening on blades 1
7 Using standard screws, attach stator blades to round mounting bracket so ignitor is orientated through cut in middle #2 Phillips F-1 1
8 Using 2 black wood screws, attach the light sensor bracket to the back round mounting plate, align holes so sensor is facing hole in mounting plate. #2 Phillips F-11 1
9 Slide in sensor so it snaps in 1
10 Attach back round mounting plate to inner burner so nozzle points into burner. Arrange so ignitor is on top of nozzle and screw in. #2 Phillips F-12 2
11 Using 6 standard screws, slide safety shroud over inner burner and fasten #2 Phillips F-1 1


Step Procedure Tools(if needed) Fasteners Difficulty
1 Place plastic insulator and wave spring into back motor cover 1
2 Place windings in cover, aligning wires with slot 1
3 Place core inside the windings, short end first 1
4 Place front cover plate on motor, screw together with 4 screws #2 Phillips F-9 1
5 Attach ground wire underneath one of the 4 screws on front cover plate #2 Phillips F-9 1
6 place the motor on the mounting bracket with the wires on the side with capictor mounting holes 1
7 Attach motor bracket to bottom of motor with two nuts 10mm wrench F-8 1
8 Attach the capacitor bracket to the motor mount using two screws #2 Phillips F-1 1
9 Slide capacitor insulator over the black and white wires 1
10 Connect one side of capacitor to each wire 1
11 Slide insulator over capacitor 1
12 Snap capictor in bracket feed wires through hole under cap 1
13 Insert compressor core with counter bore facing the compressor 1
14 Insert compressor housing with screws aligned vertically 2
15 Screw two screws to attach compressor housing to motor unit #2 Phillips F-1 1
16 Insert four fins into compressor core with rounded edges facing walls of compressor housing 1
17 Insert black filter onto compressor housing 1
18 Insert four screws to attach compressor cover to compressor/motor unit to top and bottom #2 Phillips F-1 1
19 Two gold screws on side airport on opposite side from capacitor #2 Phillips F-6 1
20 Place filter on compressor intake on capacitor side with four screws #2 Phillips F-1 1
21 Screw in gauge with hands till snug and upright 1
22 Place fan on long shaft hub first 1
23 Tighten set screw on fan #2 Phillips F-4 1


Step Procedure Tools(if needed) Fastener Difficulty
1 Place bottom outer shroud on cart so large stamped rectangle is positioned over the wheels and the metal is concave up 1
2 Place burner unit into outer shroud so the open end of the burner aligns with the non wheel end of the outer shroud 1
3 Connect air and fuel hoses to nozzle barbs, fuel in front 1
4 Using standard screws attach temperature sensor bracket to bottom shroud behind burner unit, orientate so sensor is held next to burner #2 Phillips F-1 1
5 Run temperature sensor wire through grommet towards control board 1
6 Place ignition capacitor on non control board side of the shroud above the wheel 1
8 Mount control board with two screws on shroud on the side with gas cap #2 Phillips F-2 1
9 Feed control board wires under shroud 1
10 Wire circuit board where wires fit or are labeled for black spade terminal connect one of the wires from temperature switch remaining two black to power switch 3
11 Connect chain to gas cap and frame 1
12 Mount panel using four screws F-1 1
13 Clip in metal guard to end of shroud 1
14 Feed 2 ignition cables from side through hole into burner and attach to ignitor, one on each barb 1
15 Screw four screws to attach motor bracket to bottom shroud #2 Phillips F-1 1
16 Feed wires through Grommet under capacitor and under shroud to other side 1
17 Feed air hose through hole and grommet on gauge side and connect to airport on compressor 1
18 Connect ground wire from motor and outlet to ground screw F-3 1
19 Feed wire from cover plate under shroud and connect cover plate with four standard screws F-1 1
20 Using standard screws, attach top outer shroud to bottom outer shroud enclosing the interior parts #2 Phillips F-1 1

Fasteners Used In Heater

Type # Style Size
F-1 Self-threading type B screw (sheet metal screw) #10 x .375
F-2 Phillips truss head self-threading Type BT Screw #6 x .375
F-3 Phillips truss head self-threading type BT screw with external tooth lock-washer #6 x .375
F-4 Knurled cup point, hex socket, set screw M6x1 x .6cm
F-5 Phillips hex washer head machine screw #10-32 x 1.125
F-6 Phillips hex washer head machine screw #10-32 x 1.000
F-7 Phillips fillister head machine screw #10-32 x .563
F-8 Hex nut M6x1
F-9 Phillips round head machine screw M4x0.7 x 5.5cm
F-10 Phillips hex washer head machine screw #10-32 x .75
F-11 Phillips pan head self threading type A screw #8 x .375
F-12 Phillips round head self threading type BT screw #10 x .375


DuraHeat.(2008, November 12). Portable Forced Air Heaters "User's Manual". Retrieved November 27, 2009 from

LMNO Engineering, Research, and Software. (2005, July 24). Bernoulli Equation Calculator with Applications. Retrieved November 5, 2009 from