Driving You Crazy? or Ways of Driving Your Pressure Washers Pump

Driving You Crazy? or Ways of Driving Your Pressure Washers Pump

The pump is one of the main components of your system. How it turns to produce the pressure comes from a motor electric or gas that is the end of it right? Pictures all are provided by Cleaned by Pete via his equipment and washers except the hydraulic photo, I do not have a tractor so I don't have a need for this washer.

No pumps are divided into different speeds or RPMs they also are mounted differently and have different life-spans. If you can a turn a pump slower but still achieve the desired pressure and water flow you will do the same job only with less wear and tear on the pump. Less wear and tear means a longer life who would not want their pump lasting longer? How is this done? Why would you want anything else? Well the answer starts here, what do we need to do? 

First thing is we need a pump that runs at  1700 RPM (rounds per minute). These pumps will have larger cylinders, capable of pumping larger volumes of water. With each stroke of the pistons in the pump's head more pressure and more water can be pumped out. Since the pump is turning slower it will last longer. The three most common ways of doing this are by using pulleys and belts, using a gear drive or gear driven speed reducer, and the last method which is not to common is a hydraulic pump (as a pto shaft or hd pump on say a tractor). These methods use a gas powered engine to make power and then you can transfer that power to the pump.

Top view of one of the belt driven pumps from Cleaned by Pete.

 Belts and pulleys

Belts and pulleys come in different configurations and you can "over drive" as well as "under drive" the pump by changing one or both pulleys. The main thing here is you still must have the correct size of gas engine to provide the RPMs as well as the required torque. To small of engine or to little of HP horse power can not compress the larger volume of water in the head of the pump which the pistons are trying to compress. Belts and pulleys are the most common way a commercial or industrial grade power washers are driven.

Cleaned by Pete's belt driven pump, twin belts transfer power form the motor to the pump this is a 5 gpm @ 2500 psi with a 13 hp Honda engine.

Under Cleaned by Pete's Landa skid belts provide power to the pump as well as the 110 volt generator seen on the right.  Since it is pulling a pump 5 gpm @ 3500 psi and a generator it needs a larger motor in this case 18 hp twin Briggs supplies the power.

You can see the pump and the belt and pulleys that drive it in this picture.

Gear driven or Gear Reduction

Gear driven or Gear Reduction set ups have an enclosed set of gears such as the transmission on a car. The gear ratio cuts the speed of the motor in half or there about half speed. This will let you use a belt driven pump but via the transmission you can bolt it to your engine. This makes the pressure washer a smaller and more compact size. This method is gaining popularity with pressure washer builders. This method of driving the pump still has all the advantages of the belt driven unit but as stated above the "footprint" is smaller when using a small pickup as Cleaned by Pete does this gives us more room for other needed items. Smaller footprint washers and vehicles are becoming a must when trying to stay as "green" or earth friendly.

Gear driven Hypro pump the small transmission reduces the speed of this 15 hp engine to around half to power the 4 gpm @ 3200 psi pump.

The belts and pulleys are replaced by this gear reduction or gear box transmission Cleaned by Pete's gear driven pump.

Hydraulic drive

The  hydraulic drive is not that popular but does need to have a mention. A hydraulic drive system is a drive  system that uses pressurized hydraulic fluid to drive hydraulic machinery via a vane which than can transfer those RPMs to that same pump used on the other two systems mentioned above.

PTO driven pump via the shaft on a tractor.

Hydraulic drive on a pressure washing pump

Why do we as power washers chose one of the systems listed above? I have mentioned the life of the pump is doubled it simply last longer. An other reason power washers like this system or pump it will "draw water". Drawing water means the pumps volume of water is large enough and slow enough to pull water from a tank or reserve. I does not need to be forced fed water from a water tap or a well pump system. You see big water tanks that are used in areas where there is no water supply. These pumps can create enough suction or draw to pull water from a tank or gravity feed (bottom of the water tank is above the level of the intake on the pump. These pumps with larger pistons and water volume usually move larger gallons per minute and have higher pressure. Remember GPM x PSI = TCU (gallons per minute x pressure per square inch = Total Cleaning Units) or the work our washer can do. Draw backs are these pumps cost more and are larger. They need more maintenance at times, changing oil in the transmission, new belts or belt adjustments 

The Direct Drive Pumps 

Direct drive pumps work in the same manner but turn or spin at the same speed of the engine or motor driving them. Since they spin at 3400 RPM to 3600 RPMs they wear out quicker and have smaller pistons most direct drive pumps don't have large volumes of water. They can draw some water but it is not advised to use them in that matter. Gravity feed if set up correctly will work but most have to be force fed from a water tap or some type or other pumping devise. I have used a sump pump to supply water to them, they will need the supply of water to match their outputs if you are putting out 4 GPM you need 4 gallons per minute going in. The direct drive pump is found on most consumer grade systems. 

A direct drive nickle plate pump putting out 4 gpm @ 4000 psi driven by a Lifan 15 hp engine.

A direct drive nickle pump putting out 3.5 gpm @ 2700 psi driven by a Mitsubishi  7 hp engine.

Direct drive General pump 4 gpm @ 4000 psi powered by a 15 hp Lifan engine.

You can see in this picture the direct drive housing that protects and connects the motor to the pump. Cleaned by Pete portable heated unit photo.

The direct drive pump can also be found to attach to an electric motor. Most electric motors run around 1750 RPM some run at 3400 RPM your pump must be attached and mounted to the correct size motor. Electric motors are rated still in horse power but they are classed differently than a gas motor. Torque produced in an electric motor is constant unlike a gas motor. Electric motors start and run constant even under load gas motors have governors that speed up or throttle down the engine under load to keep it constant. You can find belt driven electric power washing units also and they will have a longer life as it gas breathers do.

C frame pump mounted directly to a 1 1/2 hp electric motor.

An electric kitchen cleaning unit capable of running hot water from the kitchen boiler or hot water heater do to its special packings.

This is an old "barrel pump" set-up the direct drive pump is a Hypro twin cylinder that was the standard for carwashes in the old days.

This is a 3600 RPM C frame pump for an electric motor only via a special adaptor it is mounted to a 6 hp gas engine. A Cleaned by Pete special build.

A closer view of a "C" frame pump designed to work with and bolt on to electric motors with a "C" plate face.

This is just some highlights on driving a power washer picking which way you need will boil down to what you are looking to do with it. You need to decide on a few things cost, life, style, footprint, what will power it, are just some of the questions that should be addressed before you purchase a washer. For Cleaned by Pete and what we do we have several different washers and use several types of drives depending on what the job requires. The question is always is my motor big to run this pump. Pumps require a certain horse power and speed and much be matched to the motor or engine. You can always use a bigger motor or engine with no problems but to big of pump will not work out.