1.0 Introduction

The purpose of the project is to rebuild and make improvements to a preexisting machine. Today, large and small companies are not scraping old and outdated machines but to rebuild and install them into present or future applications. This idea was applied to an old gas-sprayer that has been lying around unused for the last 20 years.

There are times where a lot of spraying was to be done around the house. A simple hand-pumped pressurized sprayer was normally used for this chore. The problem with using this type of sprayer is the need to refill the tank many times to complete a job. In addition, when the sprayer is in use, the operator must consistently pump up the tank to keep a constant pressure. Keeping the tank pumped up enough to get a constant stream of the fluid from the nozzle after a while becomes a hassle. A better way to do this project is to have a sprayer that can hold a large volume of fluid, could be transported easily, could keep constant water pressure in the system and operate without help from an exterior water source (Miracle-Gro sprayers).

Rebuilding this machine will solve many of these problems when doing this type of chore. It will carry a large amount of water in one tank, eliminating numerous tank refills. The tank will not need to be pressurized; a gas-engine driven pump will draw water and push it out to a hose with a spray nozzle attached to it. No pumping is needed; therefore, the operator could spray without the worry about losing pressure. The operator also could spray for longer periods using this machine over using the hand-pumped, pressurized sprayer. This machine will make spraying the 40-odd-apple tree on our property a lot easier than before. The used of the sprayer could be expanded to include applying chemicals on plants, lawns and trees and applying wood cleaners on decks.

1.1 Operating Theory of the Sprayer:

The hydraulic system of the machine is simple. A tank full of water is connected to a filter, in which, is connected into the inlet of a pump. The pump pushes the water out, and it travels to a bypass valve and finally to the spraying apparatuses (wand sprayer and boom sprayer). This machine could be used for many gardening applications from watering plants to treating lawns.

The tank holds about 15 gallons of water. Water is drain through a hole in the bottom of the tank. The tank has a removable lid, which it could be filled from the top. Water travels from the tank to an inline filter, which removes large particles of dirt out of the water. The filter cup could be removed to clean the screen filter inside. After the filter, the supply line goes to the pump. The water in the line flow into the inlet of the pump. The actuator inside of the pump puts energy into the water flowing through the pump. The pump pushes the water through the outlet of the pump. The pump actuator is driven by a belt drive connected to a gasoline-powered engine.

The fluid flows from the pump to the bypass valve, the bypass valve is arranged to apply pressure to the fluid from the pump. The line is split into two. One section of the line becomes a return line; it returns fluid back into the tank. The other section of the line provides fluid to the pressure gage, wand and boom sprayers. The wand sprayer is used for spraying bushes, trees, and flowers. The flow on the wand sprayer could be adjusted by turning the handle on the end of the wand. The wand has a hose range of approximately 26 feet. This length of hose could reach many plants without moving the machine around constantly. It is the other spraying apparatus on the machine. The boom sprayer is used to spray lawns with pesticides and fertilizers. The fluid flow from the boom sprayer can not be controlled like the wand sprayer because it has an on-off switch. The boom sprayer could also be removed for easy storage.

1.2 Project Objectives:

Fix the machine so it could operate correctly.
Find and fix certain components that have worn out.
Create and build improvements on the existing machine.

2.0 Operating Instructions:

2.1 Machine Setup for Spraying:

2.11 Cleaning the Filter:

Unscrew filter cup from filter assembly, which is located under the tank.
Remove the screen filter from the filter cup and clean screen filter with water.
If needed, remove the rubber gasket from inside the filter cup and clean rubber gasket, if it is dirty.
Fit and realign the rubber gasket to the lip on the filter cup.
Replace the screen filter inside the filter cup.
Screw the filter cup tightly back onto the filter base.

Note: Clean the screen filter and filter cup before or after each use to reduce the amount of sediment that travels in the hydraulic system.

Warning: Sediment in the hydraulic system may cause irreversible damage.

2.12 Filling Tank:

Remove the lid from the tank by pulling up on the handle, taking the return line out of the tank.
Fill tank with liquid using a pail or hose to a desired level. (The maximum tank capacity is 15 gallons.)
Add the proper amount (according to the instruction on the fertilizer or pesticides container) of chemical to the liquid. Note: High chemical concentrations in any fluid may leave residues or destroy components (i.e. hoses, valves and pumps.) in the system.
Mix the contents in the tank thoroughly with a pipe or stick. Note: Any stirring stick used to stir chemical is contaminated with that chemical, discard stick immediately after use.
Replace the lid to the tank and placing the return line into the tank. Make sure that the lid is fully attached to the tank. If not fully attached, lid may come off when machine is in operation.

2.2 Setting up and starting the engine:

Check the oil level inside the engine. Unscrew the cap to the reservoir. Pour oil into the reservoir. The oil level should be up to the threading of the reservoir. Replace the cap.
Notes:
- Used SAE 30 engine oil to fill the engine.
- If the engine was running, allow engine cool for about 5 minutes before filling engine with oil.
Check and fill the gas tank. Remove gas cap. Pour gasoline into tank until filled. Replace gas cap.
Notes:
- Regular unleaded gasoline is recommended.
- If the engine was running let engine cool for about 5 minutes before filling gas tank.
Pull the throttle half way out.
Pull the choke out all the way on the engine.
Take the pull cord, grip firmly, and pull to start engine. Repeat until engine fires.
When engine fires, push in choke. Adjust throttle to increase or decrease engine speed.
To stop engine, pull both the throttle and choke out all the way.Note: After the engine stops, push in both the throttle and choke. This will prevent the flooding of the engine.

2.3 Assembling and operating the Boom Sprayer:

Line up the holes in the backing board with the holes located at the tank end of the frame.
Insert (2) 5/16” x 4½” bolts from behind the board and push the bolt assembly (bolt with washer) halfway to hold the backing board to the frame.
Attach and line up legs to backing board. Push the bolt assembly the rest of the way through the boards and start threading bolts halfway.
Align legs perpendicular to the backing board; tighten bolts the rest of the way with two-½ inch wrenches.
Line up the holes on the legs with the holes on the boom.
Again, insert the bolt assembly into the holes on the boom and legs and tighten bolts.
Attached line hose to the boom sprayer inlet located in the middle of the boom. Before the line attach to the boom; slip a hose clamp up the hose. Use a screwdriver to tighten the hose clamp.
Slip on another hose clamp onto the hose to the boom sprayer. Attach the hose to the barb connector and tighten hose clamp.
With equipment running, throw the boom switch to activate boom sprayer. (Flow control chart are Appendix A & B)
The boom sprayer could be removed for storage, loosen and remove the bolts and the boom, leaving the legs on the machine.

2.4 Operating Instructions for Spraying Apparatus:

2.41 Operating Sprayer Wand:

Unwind hose from handle reel. The handle reel is used for storage, when hose it not in use
Take the wand and the handle clockwise to open the valve to allow water to shoot outward. Turn handle counter-clockwise to shut off the water.
To rewind the hose, wrap the hose around the space between the pin and the handle.

Note: This branch of the system has a shut off valve. This should be if the valve on the wand fails to close properly.

3.0 Procedure:

3.11 Initial Condition of Equipment:

Since the object of this project was to rebuild an existing piece of equipment, things on it needed repair or replacing. Here is a list on what need to be worked on initially:

Existing engine on the sprayer was not working.
Equipment was never painted.
One wheel fell apart.
The unknown condition of the hydraulic system of the machine.

3.12 Part Repair and Replacement:

1. Replacing the engine:

The original engine on the machine was found in the trash over 20 years ago. Checking over the engine initially, there were no signs of damage to any for the parts of the engine. The engine seemed to be in perfect condition except for the gas tank. The gas tank was heavily corroded inside and could not be sealed correctly due to a large dent in the opening. It was replaced with a plastic gas tank from a scraped snowblower. As seen in the photo, the new tank had to be mounted differently from the old one. (See Figure 23 on page 18) If gas was poured into the old tank, the rust in the tank will get into the gas. It would flow into the engine possibly causing damage. Because the cap did not fit onto the tank correctly, gas would “shoot” out of the tank when the engine is in operation. There is a possibly that gas from the tank could go onto parts of the engine where it could catch fire.

After the tank was replaced and the new gas tank was filled with gas. Gas from the tank was leaking from the carburetor. Dried out seals in the carburetor caused this problem, it was disassembled and the seal were removed. The seals were place in a container of gasoline and soaked overnight. Then, the seals were reinstalled back onto the carburetor and the carburetor was placed back on the engine. When the new tank again was filled with gasoline, the carburetor did not leak anymore.

With the engine ready to be started, it was prove difficult to start it for the first time in 20 years. When the engine was found 20 years ago, it was in perfect working order. After about 25 pulls, engine failed to start and when it fired, it would not continue to go. The spark plugs were replaced, the engine was adjusted, and starting fluid was used to try to get the engine to work. After a while, none of these things worked. After doing a few simple tests, the conclusion is that the engine had no compression in the cylinder. The engine was receiving spark from the engine but it needed compression to keep it going. There are two theories why this engine would not start. One theory is the engine developed minute cracks in the cylinder wall inside the engine causing oil to ooze out over the frame. With the engine being down in the barn exposed to the weather, the engine block slowly developed cracks, which caused the loss of compression inside the block. The second theory makes more sense, over the 20 years of inactivity, the seal in the engine block deteriorated. When the seal deteriorated, the compression in the cylinder was gone, and oil oozed out of the engine block. When the machine was stripped down in order to paint, there was oil all over the part of the frame where the engine was located.

Finding a working replacement engine in the trash was going to be difficult. When an engine is thrown out, it tends to be in non-working order. A new engine for the existing setup was going to cost around 250 dollars. The engine used on this machine was a horizontal shaft engine. This type of engine is used on power equipment such as rototillers, cement mixers and chippers. There was an idea to modify the drive of the machine using a vertical shaft engine. Vertical shaft engines are easier to find in the trash, because they are normally found on lawn mowers. However, it was going to be too expensive and time consuming to modify the present setup to accommodate a vertical shaft engine.

After five months of searching for a replacement engine with no luck. An engine became available from a piece of equipment, in this case a rototiller that was going to be scraped. The engine from this piece of was in excellent working condition and equipment was rebuilt in the early 1980's. The only modification made to the machine was adjusting the mounting holes on the sprayer frame for this engine.

2. Painting the machine:

When the machine was initially built, it was not painted. A light coating of black rust appeared on the bare metal of the frame. Since this machine uses water, painting it will prevent rust from forming on the various parts of the machine. Painting it will also stabilize the structure of the frame and make it look attractive.

To prepare the machine for painting, the various working components (i.e. engine, plumbing, pump, etc.) were removed. Next, a putty knife was used to scrape off the oil gunk on the frame. The old engine leaked oil everywhere on the frame of the machine. The dirt and dust inside the barn collected itself on the oily surface making this type of gunk. The gunk must be removed from the frame for the paint to adhere to metal. The putty knife could only remove so much of the gunk. A degreaser was applied to the surface removed the rest of the dirt and oil. Then, wire brushes and sandpaper was used to remove the rust on the frame. Finally, two coats of primer and two coats of black enamel were applied to frame.

The tank was painted when the machine was built. However, there were spots of rust beginning to form around the exterior walls of the tank. To match the fresh paint job on the frame, the tank would be repainted. The rust spots on the tank were removed with sandpaper and a wire brush. Next, to even out the paint on the tank, the treated spots were painted with a coat of primer. After the treated spots dried, the rest of the tank was given two coats of primer and two coats of black enamel.

Immediately after it was built, the new axle was given the same paint treatment just like the tank and frame. The axle was to prevent rust from forming on to the metal while it waits to be installed onto the machine.

3. The condition of the wheels:

The original wheels on this machine were set of wheelbarrow wheels with a solid rubber tire. About six years ago, the one of the tires fell apart on one of the original wheels. The machine needed a new set of wheels. The new set of wheels for this project came from another project, replacing a front axle on lawn tractor. The replacement front axle came from a tractor that was in the scrap yard. After the project, there was an extra set of wheels left over. They were still attached to the axle mounts in case we needed them for the tractor. The wheels were removed from their original axle mounts and were fitted on newly designed axle. The existing axle could not accept the new wheels, because the pins on it were too short for the new wheels. The bushings on the hubs of the new wheels were wider than the ones on the old wheels.

4. The condition of the hydraulic system:

The condition of the hydraulic system on this piece of equipment was initially unknown. All that was known is that it worked when it was built. It was unknown if the long period of inactivity may cause problems with the pump or the bypass valve. After a few tests, the hydraulic system seems it was in excellent condition, except for the bypass valve.

The bypass valve is used to direct the flow of excess fluid back into the tank and creates pressure in the system. The problem with this component is the valve does not create any pressure in the system whatsoever. Inside the valve, there is a stem, which has a spring resting on a steel washer. The original steel washer was replace with a new steel washer because the original one was badly corroded. This part holds the spring in place on the stem. A leather-plumbing washer is located above the spring and steel washer assembly and it integrated into the valve stem. The leather-plumbing washer is not sealing correctly because it is worn out. One side of the washer is pushed out of position, and can not be pushed back into place. A replacement washer was to be found, but the washer may not be easy to replace since it is an unusual part.

3.13 Equipment Improvements:

Another objective in this project was to make improvements to the existing machine along with the repairs. Here is a list of improvements made to the machine:

New axle for New Wheels
New wheels
Sprayer bar
Rebuilt hose connection
New engine
Safety cage for belt drive
Hose extension

3.14 Making Machine Improvements:

1. New axle for New Wheels:

A new axle had to be fabricated because the new wheels did not fit on the original axle. The pins on the original axle were too short for the bushings on the hubs of the wheels. The retaining pin could not be place at the end of the axle. The pins are needed to hold the wheel in place.

The original axle was a simple piece of ¼” x 1” flat stock with short 2 ½” pieces of 3/8“ diameter steel rod stock welded at each end of the flat stock. Small holes about 1/8” diameter was placed at the ends of the round stock for retaining pins to hold the wheel in place. There were holes drilled into the flat stock to mount the axle onto the frame of the machine.

This new axle is a simple design using a piece of 1½” x 1½” x 3/16” steel “L” channel and a 3/8“ diameter steel rod. The steel “L” channel is about 17 ½” long and the 3/8” diameter steel is about 24” long. The piece of steel “L” channel is placed on its side. The rod is then placed in the groove in the “L” channel. The rod is centered so there will be equal spacing outside the “L” channel for the hubs of the wheels. The rod is welded to the “L” channel in six places. Then, using the original axle as a template for the holes so it could be attach to the frame. Drill holes into the axle (“L” channel), the same diameter and location as on the original. After drilling the holes, line up holes on the axle, with the holes on the axle bracket (frame). Attach it using 5/16” x 1½” bolts and 5/16” nuts with washers at each end.

At the end of the rod, drill a small hole, ¼” inch in diameter, and ½” inch from the end. After an application of lubricating grease, the wheels are installed on the axle. A 3/32” x 3/4” cotter pin is inserted in the hole and the ends of the pin are separated slightly with a slotted screwdriver. With a pair of needle nose pliers, the ends are turned up, so the pin will not fall out of the hole. The cotter pins will keep the wheels in place while the machine is being moved and maneuvered around.

Initially, when the wheels were attached to the new axis, there was a considerable gap between the end of the “L” channel and the end of the bushing on the wheel. The gap goes from the other end of the bushing, which is resting on the cotter pin near the end of the axle. The gap was around ½” inch, but when the cart was being moved and maneuvered around during initially test trial, the wheel worked back and forth across the axle. This condition creates hard handling and maneuvering problems. For instance, when the operator wanted the turn the unit to the left, the right wheel wanted to move outwards towards the cotter pin. While the left wheel, will violently move back and forth in the gap as the unit was being turned. Something is needed to prevent the wheel from moving back and forth.

To solve this problem, a bushing was placed on the axle to eliminate the gap. Many materials and standard plumbing piece were considered for making the bushing. First possible solution was to place a number of metal washers to fill the gap. A ½” inch gap was hard to fill with washers, first it was going to take many washers and second it would weigh a lot. The next possible solution was to use small pieces of pipe to fill the gap. The new plumbing for this project was mainly flexible hosing not hard plumbing. So there was no left over piping from other stages of the project. So, buying 6 feet of pipe (pipe of any type is sold in 6 feet intervals) to make two ½” inch bushings was very impractical. The final solution was to buy a 1” long, ½” diameter PVC pipe coupler.

The coupler was cut in half using a miter box and hand saw. After it was cut, the piece was then deburred and cleaned with a file. The cotter pins and wheels were removed from the axle. The finished bushings are slid in position on the axle, and followed by wheels and cotter pins. With the bushing in place, the wheels are not to slide back and forth when the machine is being moved. With the bushing in place on the axle the handling performance of the machine improved.

Overall, this new axle is better that it’s predecessor, because the “L” channel is lot stronger of a shape than the shape of the flat stock. The “L” channel could handle vertical force placed on the axle better than flat stock. In addition, “L” channel is equivalent to the flat stock in handling horizontal forces acting upon the axle. Compared to the design of the original axle, the “L” channel design has additional strength from the round stock welded on the “L” channel, running the entire length of the piece.

2. New Wheels:

As mention above, the wheels came from a lawn tractor. The wheels that were on this piece of equipment were old wheelbarrow tires. However, they seem inadequate for the purpose that they served moving a 50 pound machine over rough and varied terrain. The tires and wheel assemblies from the tractor were made for conditions like this. With these new wheels, the machine seems easier to handle than with the old set of wheels. The old set of wheel would become stuck in small ruts in the lawn and was hard to push over the ground and up hills. The new set of wheels could easily overcome all of these obstacles.

3. Boom Sprayer:

The major improvement on this machine is the addition of the boom sprayer. The purpose for the boom sprayer is to do jobs that the spray wand could not do adequately (i.e. spraying lawns with fertilizer or weed killer with the wand sprayer). The spray wand is normally used for spraying plants and trees. Home and garden sprayer that are commercially available at home center and farm suppliers have both a wand sprayer and a boom sprayer.

The boom sprayer was designed to fit on the frame located in the back of the machine. It needed to be long enough to cover as much potential spray area as possible in one pass. It also was designed to fold up or disassembled easily when the sprayer is not in use. If the boom could be disassembled, it has to be a simple design, with few steps and tools needed for assembly and disassembly. If the boom could be folded, the foldable extensions must able to be tied up for storage. As well as, when the boom is in use the extension must lay flat for the spray boom to work properly. The existing hydraulic components on the machine could handle the addition plumbing needed for the boom sprayer.

If a foldable design were to be used, it would be constructed of either copper or PVC piping. Copper piping is the most commonly used in plumbing because it is durable and could be worked into any design. A tentative design for the foldable boom was going to be a piece of copper or PVC pipe, ½” inch in diameter, attached to the frame using pipe holders. The pipe would have been about 24” inches long, which is longer than the width of the frame (which is 17 inches wide). The short piece of pipe extended beyond the frame, along with a small piece of flexible tubing, will be used to attach the extension arm to the main pipe. The small piece of flexible tubing would have acted like a hinge connecting the two pieces together. When the sprayer is in use, the extension arms would fold out to an approximate length of about 60 inches. When the sprayer not in use, the arms will fold up and be bounded with a bungee cord for convenience and easy storage. Both, the main pipe and the extensions would have a series of small holes (about 1/16 inch in diameter) drilled into it. The pipes would look like a common fan sprinkler. The holes in the pipe would have pointed outward and upward away from the machine. When water flows through the pipes and travels through the holes, it will create a gentle arc of water aimed toward the ground. With the way the sprayer would have been oriented, the water will not soak the area that is being sprayed.

One problem with using copper piping that is exposed to the environment and water dripping from the project; the plumbing would start to corrode after a while. For this application, the plumbing should hold up to the environment that is subjected to. This is where PVC plumbing becomes attractive. PVC plumbing has similar physical properties to copper, but it does not corrode or is affected by the environment. Another drawback was copper pipe needs a lot of preparation before putting it all together. The connecting ends of the copper piping need to be clean thoroughly with sandpaper and flux, so the soldering could adhere to the pipe, to create a good joint. PVC pipes are joined together with adhesive. The cost of the parts needed to make the sprayer boom are equal. Except, the equipment and supplies needed for soldering copper piping tend to be more expensive than other types of plumbing. For example, a propane torch cost around 35 dollars, while PVC pipe cleaner and adhesive is about 20 dollars. In addition, assembling the plumbing potential here at school at one point, it made sense to use PVC plumbing, because of the ease of assembly.

There are problems trying to build a simple workable folding boom sprayer. The first problem is the lack of time and money for this project. Making this folding boom sprayer could easily be another application project altogether. Making this would also go beyond the focus of the project, which is rebuilding a gas-powered sprayer with some improvements to the design. Indeed, adding an elaborate spraying boom is an improvement; it would be more work to create that one component than it is to rebuild the whole machine. Since, time constrains forced another boom sprayer design to be created. This design must be practical like the foldable unit, and could be taken apart easily for storage. Also, the parts that make up the boom sprayer must be affordable and could be assembled easily. This becomes the genesis of final design, which is a combination of modular tubing and agriculture spraying parts.

This boom is a simple design containing a 2” x 4”, 61¼ ” inches long with 4 agricultural sprayers 20 inches apart attached to the board. The boom is attached to wood frame that raises the boom approximately 25” from the ground. Originally, the boom was attached directly to the frame of the machine. However, the frame was too low for the sprayers to work effectively. The spray stream from the sprayers should touch each other for the boom to work effectively. When the boom was initially tested with the boom attached to the frame, the sprayer was only covering less than 50% of the potential coverage area. This is why a wood frame was built to increase the distance from the ground to the tip of the sprayer, to increase the effectiveness of the sprayer.

The wood frame is made various lengths of 2” x 4”’s, bolted together for easy maintenance and disassembly. Originally, a 2” x 4” x 17½ “ backing board was attached the frame because the wheel jet out about an inch beyond the frame. With the wheels in the way, the boom could not be attached to the frame directly without a backing board. When the frame-attached boom did not work out correctly, the backing board was retain with the frame assembly to first provide a bit more body to the assembly. The second thing was moving the spray boom away from the wheels. Having the sprayer applying water to the wheels, this reduces the effectiveness of the sprayers. The two 2” x 4” x 16” uprights are attached to the backing board with 3” x 5/16 ” -- 18 bolts. The boom is attached to the uprights with the same type of bolts. The uprights were made to increase the height from the ground to the tip of the sprayers, thus increasing the amount of area being sprayed per pass of the machine.

The fluid passes from the plumbing extension to the boom using 3/8” ID tubing. The tubing goes to a tee, which distributes water equally to both sides of the boom. Each side of the boom has plumbing connecting to two spray heads. From the tee (“C” according to drawing on next page) in the middle of the boom, water travels through a 10-inch long tube to the first tee. This tee has the first sprayer from the middle (“B”). Then, the water travels through the first leg of the tee (“B”) to the first sprayer. Water can also travel through to the second leg of the tee. The second leg of the tee goes through a 20-inch long tube into an elbow ending up at the sprayer at the end of the boom (“B”). The other side of the boom has the same setup as just mentioned.

4. Rebuilt Hose Connection

The original connection for the wand hose had many problems. One such problem is the kinking of the hose at the barbed connection whenever the wand sprayer was being used. With no warning, the flow in the wand will decrease and the spray will eventually cease altogether. This happens more often when the operator is trying to reach an object far away from the machine. The operator is extending the hose to the entire length in either direction (left or right) to reach that object. This causes the chinking in the hose.

The original hose connection was going towards the tank, about 90 degrees from where it should be, facing away from the machine. Since, the original connection was placed wrong, the new plumbing extension corrects this problem. With the extension to the existing plumbing for the spray boom, the connection was moved to a “better” place onto the frame of the machine. It is now located on the frame, perpendicular to the frame. It works better because it does not kink the hose, if the hose is extended all the way and bent either right or left of the hose connection.

The new plumbing for the extension connecting both, the sprayer hose and the spray boom assembly was built using galvanized steel and brass plumbing fixtures. The existing plumbing on the machine is galvanized steel plumbing; it was easy to extend off that. Some of the brass fixtures such as short connectors, shut off valves and hose connectors, has similar pipe threading to the galvanized steel plumbing.

The plumbing extension is divided into two parts, one branch goes to the spray wand and the other branch goes to the boom sprayer. The spray wand branch has an auxiliary shut off valve attached to the frame. This valve can be shut off the water supply if the hose or wand sprayer is removed or the valve on the sprayer wand fails.

The hose could be removed from the machine simply by unscrewing the pipe clamp on the hose connector. This is done when the boom is being used. The hose must be removed when using the boom sprayer because the heat from the muffler will melt the hose or possibly catch the hose on fire, which is dangerous.

5. New engine

The new engine is definitely a better improvement over the existing engine. First, the new engine works. Second, no major adjustments were needed to fit the engine into the existing machine. The engine needed new mounts drilled into the plate; the old mounting hole did not fit the engine well.

	Old Engine	New Engine
Horsepower	2 HP	4 HP
Gas Tank Capacity	1/3 gallon	½ gallon
Type of Throttle	Governor	Adjustable
Works	NO	YES

Table 1: Old and New Engine Comparisons

One thing that made need replacing some time in the future is the drive belt. The drive belt is too long for the modified setup. However, the drive works even with this problem.

The new engine is more powerful than old engine. The new engine also has a larger gas tank for longer running time. The new engine has an adjustable throttle over the old engine’s governor. With the adjustable throttle, the engine speed and pump output could be greatly and careful controlled. This may lead to better overall performance in spraying.

6. Safety Cage for Belt Drive:

With the slack in the belt drive, an idea came up for a simple protection shield for the drive. There is a possibility when the machine is being used, a branch or a small stone could get into the drive and cause problems with the machine. If something gets into drive, it will not shoot out at the operator. In addition, the protection shield will protect little children from the drive assembly. Little children have the tendency to stick their finger everywhere especially in mechanisms. On all gardening equipment made recently, come with some sort of safety equipment. Most drive mechanism on garden equipment has safety shields on them.

Initial ideas for this guard was to cover the entire engine and pump area with angle iron and mesh screening. The problem with that was it would add too much weight to the machine and the moving components of the machine will be covered. It will be hard to service, because the shroud will have to be removed for even the smallest amount of service.

The second and final plan is to just cover the belt drive. This cover will protect the top and front of the belt drive. It is made out of scrap pressure-treated wood with leftover mesh screening. A single piece of wood with the dimensions of 1” x 11/4” is cut into 3 pieces, two 12-inch pieces and one 16-inch piece. The two 12-pieces are located at the ends of the 16-inch piece. The two 12-inch pieces of wood are perpendicular to it. Then, it is attached with 2” drywall screws to the 16-inch piece. Next, the screen is shaped and fitted over the created frame, and a side cutter is used to cut a strand of screen to mark the dimensions. Then the screen is folded at the mark, and is taken to a bench grinder where the strands are cut to make a clean edge on the screen. Now, the screen is attached to the frame with 3/8” inch staples, spacing them about ½” inch from each other.

Next, place the finished guard on the lip of the frame and attach 7-inch long cable ties to the frame, through the screen. If service is necessary, the cable ties are cut with a pair of side cutters and the guard could be removed.

When the guard was place around the belt drive, there was a problem with the pulley and belt rubbing against the frame. There was a possibility that if the pulley or the top of the belt will grab the guard frame, the forces acting upon the pulley will rip the guard from the machine. There is a possibly that the guard will eject and hit a bystander or the operator. To minimize the possible of this, the corners of the upright boards were chamfered to make a gap between the pulley and the guard. The chamfer was made by running a block plane along the corner of the wood until there was a good gap between the two.

7. Hose Extension Connection:

The hose-extension connector was made from leftover parts and parts that were ordered by mistake. After, doing all of the plumbing for the boom sprayer, there was 6 feet of leftover hose. This length of hose was suitable enough to justify doing this. Other parts include a 3” chrome pipe section and two female hose adapters. The 3” pipe section was going to being incorporate into the line to the boom sprayer, but no room for this into the layout. The female hose adapters were bought by mistake. This was supposed to be male hose adapters for the boom sprayer.

The hose adapters were threaded on to each end of the pipe section. The hose extension is attached to one of the nipples of the assembly and the hose is secured with a hose clamp. The other end of the hose-connector goes into the end of the black sprayer hose, and it is secured with a hose clamp. The other end of the hose extension, the wand sprayer is attached to the hose and is secured with a hose clamp.

The range of the wand sprayer is expanded by 6 feet with this hose connection, so the wand sprayer could reach more trees or plants.

4.0 Discussion and Conclusion:

This project ran too long; it should have been done a long time ago. Problems with finding a replacement engine, parts for the sprayers and the inclement spring weather delayed the completion of the project. This project was very challenging; it dealt with the practical use of basic principles of hydraulics. Also, how to apply the existing knowledge into an application. Some of the principles used in this project dealt with the behavior of flow and pressure in a system. The most difficult part of the project, besides finding a working engine, was building the boom sprayer. Numerous options and different parts can be used to build this portion of the machine. As with all projects, time and money dictates, in which options are feasible to make a working component on a machine.

I learned from this project, whenever a part or process is added or removed from a machine, make accurate records of it or write it down. Trying to remember something that happened six or more month after the event is very hard. It is also very hard; to accurately reconstruct what happened if it was not written down somewhere. Another thing learned from this project, was the need to find out if an application project, which has a gasoline engine, could sit out of the dorms. I found out the hard way. Leaving any flammable substances outside of the dorms, whether in a container or not, violates the state fire codes. It is good to check out, if a project with a gasoline engine could be placed in the lab or outside of the dorms.

Last updated: 03-24-2002 Copyrighted 2000, 2002 Christopher Pohorence