Frequently Asked Questions

Elliott Machine can provide a new chassis or build a unit on your provided chassis, new or used.

Air operated oil pumps utilize air pressure from the on board air compressor to pump oil. Because of the simplicity of air pressure, air pumps are usually referred to as being less maintenance. Hydraulic oil pumps are driven by a hydraulic motor, which in turn, requires the truck to have a hydraulic system (pump, reservoir, valve, etc.). However, the pumping capabilities of hydraulic driven oils pumps are the advantage. Elliott Machine can provide estimated flow rates for your next fuel/lube truck.

Air operated oil pumps are commonly referred to with a ratio, such as 5:1. This means that for every pound of air pressure that goes into the pump, it produces 5 pounds of fluid pressure to pump the fluid. Most double diaphragm pumps are 1:1 ratio. A higher pressure output will help in pumping thick or viscous oils, but does not always mean it will provide a higher volume delivery. Elliott Machine uses Graco 5:1 ratio oil pumps on air driven units.

An open or closed center description refers to the valve used in the hydraulic system. An open center valve allows hydraulic oil to flow through the valve continuously and when a function is needed, it diverts that flow. A closed center valve uses load sensing capability to stop the flow of hydraulic oil when it is not needed and increases the flow of hydraulic oil when it is. Elliott Machine load sense hydraulic system can increase the flow and pressure dependent on how many systems are used at once.

Under Parts & Service on this website, you have access to our parts and service center as well as detailed on-line manual.

We have records and detailed information regarding all units we manufactured, regardless of the age.

In the United States, diesel fuel is reclassified as a combustible liquid instead of a flammable liquid allowing it to be carried in a non-spec container. Elliott Machine builds their fuel tanks as if they would be code, even though it is not required

The Code of Federal Regulations governs the amount of hazardous material under what is known as a reportable quantity. This means that if a set amount of material (around 119 gallons of fuel in this case) is spilled, it needs to be reported and can cause a serious threat or safety concern to the area. Some companies believe that plumbing a series of tanks together allows them to avoid the reportable quantity and treat the unit as a non-hazmat unit. However, at any time in which the unit has more than one tank open, it no longer meets the criteria and contains a unit with a reportable quantity. This is a dangerous and unethical way to skirt the regulations designed to keep our highways safe. Elliott Machine believes that it is our duty to inform our customers of the latest rules and regulations.

Thermal expansion is a largely unknown issue that occurs when an enclosed system is heated. When a fluid's temperature rises, the pressure inside does as well; at a rate of nearly 44 psi per Fahrenheit degree (F)*. To put this into perspective, when a liquid filled hose goes from an overnight temperature of 54 deg F to 94 deg F (40 deg rise in temp), the system pressure inside the hose would increase by 1760 psi! That is why using quality hose and fittings rated four times higher than the normal operating pressure is so important. Elliott Machine Works can also incorporate a thermal relief valve in your system that allows the fluid to return back to the tank if the pressure exceeds the normal operating parameters.
*figures are from an independent study using a similar setup to that of an Elliott Machine Works lube system

Even though Elliott Machine Works tanks are built with superior material and design proven from decades in the field, like all tanks, they need to breathe. Over time vents can plug up from dust, dirt, and other liquids. As the liquid in the tank expands or contracts due to temperature changes, if a tank is not vented, that change in expansion or contraction will cause an increase in pressure or vacuum within the tank. Increased pressure or vacuum within a tank will cause premature fatigue and failure to the tank material. Another way pressure or vacuum is increased inside of a tank is by fluid movement (bouncing around on a job site or simply pulling liquid out into a pump). We recommend that tank breathers be inspected on a routine basis and replaced annually or if they have been saturated with liquid from an overfilled tank.