New Strength for Fire and Rescue Extrications

NEW STRENGTH FOR FIRE AND RESCUE EXTRICATIONS

BY FRED KNOWLES
 

Industrial fire and rescue companies can never have too much power when it comes to extrication incidents. Plane crashes, train wrecks, and large-scale production equipment accidents can tax the resources of even the best-equipped organization.

Recognizing the need for reliable, smooth-running hydraulic power for heavy-duty extrication, we set about developing a new pump design especially for industrial fire and rescue applications. Our primary objective was simultaneous multi-tool operation with high reliability.

Three factors were foremost in our thinking as we began the work:

	1.	Because reconfigured OEM pumps tend to fail in use or provide limited power, rescue tool requirements would exclusively define design standards. We wanted to overcome such limitations as hydraulic fluid failure and unreliable pump pressure while providing a low-cost solution.
	2.	Dependable, long-life operation would be an absolute requirement. To meet this standard, the pump had to meet the following specifications: effective oil filtration; efficient oil cooling for continuous duty; multiple device operation; and extended hose runs to support device operation remote from the pump. Our specifications required overcoming hydraulic fluid breakdown, which occurs regularly at high temperatures in heavy-duty applications. Another requirement was the ability to operate three devices simultaneously. Military and civilian aircraft crashes and production facility and construction accidents can place extraordinary demands on fire and rescue personnel. We wanted to strengthen response capability while enhancing the confidence of the rescue teams using our equipment. Extended hose runs would give the tool operator added flexibility and better protection from accidental fuel ignition. Also, keeping the power source remote from the accident site shields victims from destabilizing noises.
	3.	Diesel would be the pump’s primary power source. This would ensure safe, steady operation and a ready source for electric power--invariably a requirement when lighting or smoke fans are needed at an accident scene.

DIESEL POWER ADVANTAGES

Diesel power has several advantages in fire and rescue applications. It can draw on diesel vehicles` main fuel source, making it inherently safer than gasoline engines in rescue situations in which high temperatures or hazardous conditions are a factor. The ability to power up cabinet-mounted diesel systems before arrival at the scene is another plus. With a system up and tools attached, personnel can hit the ground running and perform extrication without delay. Heavy-duty design in diesel engines supports virtually nonstop operation and extended- duty cycles. Diesels also can operate under temperature and climate extremes.

For a power source, we chose Westerbeke Diesel. This U.S.-based company has a proven record in fire and rescue and mobile medical applications.

DEVELOPMENT CHALLENGES

Preliminary planning pointed to a positive outcome, but actual development proved challenging. Deciding to go with diesel was straightforward, but designing the pump was another matter. With no OEM supplier that came even remotely close to meeting our requirements, we realized we had to build our own device from the ground up.

The XRT Rescue Tool Power System (as it was later named) had to be compact enough when combined with a Westerbeke generator to qualify as a System 1 tool and capable of being upgraded in the field to qualify as a System 2 or 3 tools as funding or demand allows.

Operating efficiency was another factor: Sufficient diesel power needed to be reserved for electric generation while maintaining simultaneous operation of up to three hydraulic tools operating at 5,000; 10,000; or 10,500 psi.

To get a sense of the tradeoffs we faced, a single tool operating at 10,500 psi subtracts 1.2 kilowatts from electric power availability. At 5,000 psi, the loss is .75 kilowatt.

Although configuring a system with additional power-generating capacity is an available option with the XRT, we needed to keep our eye on our primary goal: to create a compact, multi-tool hydraulic power source with accessory electric power at a price accessible to a majority of users.

Pump design requirements were extreme--the unit had to be highly efficient, lightweight, compact, and modular. The final design was a high-pressure pump with individual elements, the failure of which would not affect the remaining pump elements operating other tools. The XRT`s power range is from zero to 10,500 psi.

PUMP WITHIN A PUMP

The XRT features a "pump within a pump"--a low-pressure system for each tool port that assists in opening and closing individual tools. With a tool fully closed, its capacity is redirected back to the XRT`s main reservoir.

Should a low-pressure pump element fail in the field, it is automatically locked out of the general operating circuit. Open/close operating speed is reduced when this function is assumed by high-pressure elements, while high-pressure cutting or jacking is still maintained at full pressure.

As inferred earlier, both high- and low-pressure circuits within the pump share a common hydraulic fluid reservoir, but both pumps discharge separately into the common control block. The block has dedicated chambers--one for each tool port--creating another layer of dependability for the XRT.

Experienced fire and rescue personnel know oil temperature is a significant factor in pump operation and reliability. A dedicated fan/radiator subsystem cools the oil in the XRT, and a temperature switch activates the fan at 1107F. The air-intake housing directs air against the pump radiator, thus providing a backup cooling system. An optional 300-watt oil heater is available for use in cold climates that require system preheating for operational readiness. A 10-micron, full-flow spin-on oil filter is built into the return line to trap sand, dirt, and other debris that invariably enter the system when tools are changed at the accident site.

LOOKING AHEAD

The XRT design's utility will be confirmed in the long term by the lives it helps save; short-term results suggest we are on the right track. Fire and rescue companies across the country have

responded favorably to the XRT. At this writing, a substantial OEM has entered into negotiations to license the XRT design. We are able to produce the product on demand with numerous installing distributors nationwide. Technical questions are welcome. The XRT Rescue Tool Power System has ports for up to three tools.

FRED KNOWLES is vice president of XRT Power Systems a division of Hansen Marine Engineering of Marblehead, Massachusetts.

http://xrtpowersystems.com/xrt-hydraulic-rescue-pumps/

As seen in the publication
Fire Engineering August, 1997