One significant change in the realm of pumps is that there is an even wider variety of configurations to meet different needs. Although the traditional midship pump is still used on most apparatus, many customers have found that power-take-off pumps, engine-driven pumps, front-mount pumps, hydraulically driven pumps or even rear-mount pumps offer them certain advantages.

Traditional midship pumps are driven by the main vehicle driveshaft through a split-shaft transmission case that usually is integral to the pump. Available in ratings from about 500gpm to 2,000gpm or more, they're mounted above the vehicle frame rails, halfway along the length of the vehicle. Midship pumps include a full range of flow rates and pressures that are limited only by the horsepower of the vehicle engine. Because they usually are located just behind the cab, midship pumps are also easy for the driver/engineer to access. However, they usually take more space and can't be operated while the vehicle is moving.

Engine-driven pumps are driven by separate gasoline or diesel engines. They are available in a wide range of ratings from about 50gpm up to about 1,500gpm. Larger pumps usually are mounted crossways on top of the vehicle frame rails, but smaller pumps can be mounted in an open area of the body or inside a compartment. The biggest advantage of engine-driven pumps is that they can be operated independently of the vehicle at any flow and pressure, whether the vehicle is stationary or moving. The disadvantages include the extra weight and cost of the engine, which can be significant with larger pumps. Engine-driven pumps are popular in wildland, wildland-urban interface and some tanker applications.

PTO pumps are driven by a power-take-off from the vehicle transmission through a separate driveshaft. They are available in ratings from about 100gpm to 1,500gpm and are mounted above or below the frame rails, aft of the PTO. These pumps are less expensive than midship pumps and offer a more flexible and compact installation. They also can be operated while the vehicle is either stationary or moving. Unfortunately, flow rates and pressures are limited by the horsepower rating of the power-take-off itself. Another disadvantage is that pump-and-roll performance varies with vehicle road speed. PTO pumps are popular in for tankers, quick attacks and certain wildland apparatus.

Front-mount pumps are powered by a power-take-off from the front of the vehicle engine through a separate driveshaft. Available in ratings from about 500gpm to 1,750gpm, they're mounted directly in front of the vehicle radiator. Front-mount pumps are known for their ease of maintenance and drafting, as well as for having more room in the body for compartments and a larger water tank. The disadvantages include partial blockage of air flow to the radiator, exposure of the pump to front-end collision damage, and a limited choice of pump and chassis suppliers. Although sales are low, front-mount pumps are still popular in applications such as rural pumper-tankers and water supply pumpers.

Hydraulically driven pumps are powered by a hydraulic motor connected through high-pressure hoses to a hydraulic pump driven by the vehicle front-engine PTO. Available in ratings from about 100gpm to 1,250gpm, hydraulically driven pumps have a good range of flow rates and pressures. Installation is flexible, and the pumps can be operated while the vehicle is either stationary or moving. A hydraulic compensator automatically adjusts for variations in engine speed to maintain constant pump performance, which makes them ideal for pump-and-roll operations. However, they are more expensive than PTO or front-mount pumps. There's also a more limited choice of pump and chassis suppliers. Hydraulically driven pumps are popular for wildland and wildland-urban interface pumpers.

Rear-mount pumps are the latest configuration to catch the attention of fire department customers. They have been used in Europe for almost a century, but they are relatively new in the United States. Rear-mount pumps may be driven off a split-shaft transmission, like a midship pump, or off a transmission power-take-off, like a PTO pump. They are available in ratings from about 500gpm to 2,000gpm or more and are located behind the rear wheels. The advantages of rear-mount pumps include a shorter wheelbase for improved maneuverability, greater space for compartments, and the flexibility to locate the pump panel on either side or at the rear. The disadvantages include a longer pump driveshaft and greater distance from the cab to the pump panel. Rear-mount pumps are gaining popularity for urban, suburban and rural applications. Some manufacturers predict their use will continue to grow in the near future.

What else is new?

In addition to new configurations, the new generation of pumps includes designs that are longer-wearing, less heavy, more compact, more efficient and more corrosion-resistant. (See sidebar on page 111.)

The new Seagrave Triton is a midship pump with ratings from 1,000gpm to 1,750gpm. According to the manufacturer, the Triton is 30% lighter than most other conventional pumps, which allows up to 500 pounds more weight capacity for equipment or water. The pump transmission is rated up to 20,000 foot-pounds of torque, which allows the pump to be matched to the latest high-torque engines.

In addition to the standard cast-iron pump construction, the Triton can be specified with either cast-bronze or an electroless nickel-coated cast-iron material for the case, housing and suction heads to help prevent corrosion. The electroless nickel coating has the added advantage of providing a high wear hardness for the surfaces, which can result in a longer service life.

All Triton pumps are pre-configured to accept Seagrave's new 220cfm compressed-air foam system driven through the pump impeller shaft and activated by a hot-shift electric clutch.

Hale introduced its Stainless Max rear-mount pumps last year with ratings of 1,000gpm to 1,500gpm, and the line now includes midship pumps with ratings of 1,250gpm to 1,500gpm. Both the rear-mount and midship pumps feature high-strength, corrosion-resistant stainless-steel components and self-lubricating, self-adjusting mechanical seals for reduced maintenance. They are available with stainless-steel suction and discharge manifolds.

The Hale Qflo midship pump remains one of the company's best-selling models and is available with ratings from 750gpm to 1,250gpm. This compact, lightweight pump has received several upgrades, including new discharge and packing options and improved flow passages for better performance.

The latest introduction from Hale is the MBP booster pump with ratings of 750gpm to 1,000gpm. This compact, high-efficiency pto pump is designed for tankers and other applications where high flows are needed from a small package. It features Hale's new Silent-Max gear box for quiet operation.

W.S. Darley has expanded its line of hydraulically driven pumps with the addition of 1,000gpm and 1,250gpm ratings, which should appeal to customers that protect wildland-urban interface areas where they need to make wildland pump-and-roll attacks as well as provide structure protection.

To complement the operation of the company's hydraulically driven pumps, Darley recently introduced the patented AutoPressure control system that adjusts the output of the hydraulic pump to maintain a preset water pump discharge pressure under varying drive conditions. The Darley PSPC pump is rated at 1,000gpm to 1,500gpm and can be mounted midship or at the rear. It includes an integrated 225cfm air compressor to provide high-performance water or CAF capabilities.

Darley also introduced two new lightweight, compact diesel engine — driven pumps capable of producing rated flows up to 250gpm as well as high pressures suitable for wildland firefighting.

Waterous builds a wide variety of pumps for all applications. Two of their newest pumps will be displayed at the IAFC's Fire-Rescue International in New Orleans: the S100 rear-mount pump that can deliver up to 2,000gpm and the E600 engine-driven pump with a 73hp engine.

American LaFrance offers their Twin Flow midship pumps with ratings from 1,000gpm to 2,000gpm. The pumps feature helical constant-mesh gearing for strong and quiet operation, self-adjusting seals for reduced maintenance and an environment-friendly oil-less primer.

No matter what pump you currently use, you should probably consider the advantages of the new generation of pumps when you specify your next apparatus — you just may find something to get pumped up about.

21st-Century Corrosion

Dealing with the problem of corrosion was a lot easier 50 years ago when pumps, tanks and the rest of the plumbing system on fire apparatus were made from thick-walled cast iron or galvanized steel. The sheer mass of the metals and the protective zinc coating of the galvanized steel kept corrosion problems to a minimum. If corrosion was especially severe in certain areas of the country, the water tank usually took the hit before the pump or plumbing were affected.

About 10 years ago, that situation changed when new apparatus started being built with plastic water tanks that didn't corrode. While that was good for the tank, it simply shifted the corrosion problem to other parts of the system. When some customers began noticing corrosion in the piping and valves, stainless-steel pump manifolds and valves were introduced to protect those components. In turn, that shifted the corrosion problem directly onto the cast-iron pump.

To solve this problem, several pump manufacturers offer pumps that feature components made from a variety of corrosion-resistant materials. Depending on the severity of the corrosion problem, these pumps can be a low-maintenance solution that works well with stainless-steel plumbing and plastic tanks.

Other manufacturers have decided to continue to offer cast-iron pumps but have designed highly reactive metal probes, or “sacrificial anodes,” that can be inserted inside the pump suction or discharge to react with the water, instead of having the corrosion attack the pump itself. This can be a low-cost solution to the corrosion problem, but it does require periodic maintenance to check and replace the anodes.

Most pump manufacturers agree that local water properties are a key factor in determining the corrosion potential in a given geographic area. For example, W.S. Darley & Co. studied the problem and suggests that two common water-quality tests — one called the Aggressive Index, and the other called the Langelier Index — may indicate whether a department needs to be concerned. [Ed.: See July Product Focus.]

But the problem doesn't end there. A new type of corrosion, called Microbiologically Influenced Corrosion or MIC, can occur when certain microbes found in water supplies form a thin film of living material on the surfaces of pipes, fittings and other metals. As the microbes grow and digest materials in the water, they produce substances that can attack even the most corrosion-resistant metals.

This type of corrosion has appeared in fire sprinkler systems, power plant cooling piping and other industrial water systems. Several different types of corrosion have been identified, each caused by a different type of microbe.

A great deal of scientific research has been conducted on MIC, but there is no single way to stop it. Draining the pump and plumbing between uses may offer a solution for departments that have infrequent fire calls.

No matter what the cause, corrosion is a serious problem that can effectively put your apparatus out of service if left unchecked. If you are experiencing corrosion in your pump, tank, valves or plumbing, you should contact your apparatus or pump manufacturer for advice.

Pumps

American LaFrance
843-486-7400, 888-253-8725
www.americanlafrance.com

W.S. Darley
708-345-8050, 800-323-0244
www.wsdarley.com

Hale
610-825-6300
www.haleproducts.com

Seagrave
715-823-2141
www.seagrave.com

Waterous
651-450-5000
www.waterousco.com

INSERVICEEXTRA.COM

Check out “The Advantages of Front-Mount Pumps” in the August edition of In Service Online.