5 Pumper Apparatus Overview

5 Knowledge Objectives (1 of 2) Explain the importance of understanding the fire pump and its systems. Describe the exterior and interior features of a pumper. Define the term pump. Explain the basic operations of positive- displacement pumps and centrifugal pumps.

5 Knowledge Objectives (2 of 2) Explain the different types of positive- displacement pumps. Explain the different types of centrifugal pumps. Describe a single-stage pump and a two- stage pump.

5 Introduction Without pumps, fire fighters cannot discharge water under pressure to extinguish fire. The driver/operator of the pump apparatus must understand how pumps operate to be able to fix problems that may arise. Do not memorize a sequence of tasks; the driver/operator should have a thorough understanding of how the pump operates.

5 Exterior of the Pumper (1 of 4) The pumper is a very basic fire apparatus. –Large fire pump with hose and tools to extinguish fires –Most common fire apparatus –Cab sits on a steel frame. –Attached to the frame are storage compartments and the fire pump. –Ground ladders are mounted on the side or stored inside the compartment at the rear.

5 Exterior of the Pumper (2 of 4) Supply hose and attack lines are stored in the hose bed. –May be uncovered or covered with a tarp for protection –Most pumpers carry preconnected attack lines for quick deployment.

5 Exterior of the Pumper (3 of 4) The pump panel is the most notable device on the apparatus. –May seem confusing until the driver/operator learns the basics of pump operations –Covered in stainless steel and has multiple levers and gauges

5 Exterior of the Pumper (4 of 4) Courtesy of Jim Hylton

5 Interior of the Pumper: The Cab Inside the cab are all the controls to operate the apparatus. –Interior controls on the engine apparatus are very similar to those on other large vehicles with few exceptions. Controls to engage the fire pump or to operate emergency lights –Fire apparatus is not like any other vehicle and should not be operated like other vehicles

5 Pumps (1 of 3) Fires are extinguished when the proper amount of water (GPM rate) is applied. –Water is directed through a nozzle at the required pressure to give the water stream enough reach to penetrate to the seat of the fire. –Pump pressurizes the water used to attack a fire –The fire pump is defined as a provider of liquid flow and pressure dedicated to fire protection.

5 Pumps (2 of 3) Pumps alone do not create pressure. –Pumps displace fluid, which causes fluid to move or flow. –Resistance to flow creates pressure. –Higher pressure means less volume or flow. –Higher flow means less pressure. –Pumps cannot provide a high pressure and a high volume at the same time.

5 Pumps (3 of 3) Two sides to all pumps –Intake side is where the water enters the pump. Referred to as the “supply side” since it is where the water is supplied to the pump –Discharge side is where the water exits the pump.

5 Types of Fire Pumps Fire service uses two types of pumps: positive-displacement pumps and centrifugal pumps. –Each relies on different operating principles. –Each offers different features.

5 Positive-Displacement Pumps (1 of 9) NFPA 20: A positive-displacement pump produces flow by capturing a specific volume of fluid per pump revolution and reducing the fluid void mechanically to displace a pumping fluid. Positive-displacement pumps rely on tightly fitting parts to function properly. –Ideal for use as a priming pump for centrifugal pumps

5 Positive-Displacement Pumps (2 of 9) Can be used as high-pressure auxiliary pumps or portable pumps –Efficiency depends on the close-fitting moving parts. –Performance will deteriorate with wear and excessive use. Two classifications –Rotary pumps exhibit a circular motion. –Piston pump have an up-and-down motion.

5 Positive-Displacement Pumps (3 of 9) Piston pumps –Use a cylinder to contain the fluid –Draws water from the intake side and pumps it out the discharge side –Three moving parts: piston, intake valve, and discharge valve Two types of piston pumps: single-acting and double-acting

5 Positive-Displacement Pumps (4 of 9) Single-acting piston pump –Operation is very simple. –Similar to a squirt gun Every pump on the lever discharges fluid from a single-acting piston pump. –Water is discharged only on a downward movement, creating a pulsating effect. –Single-acting piston pumps are not suitable for use on an attack line.

5 Positive-Displacement Pumps (5 of 9) Adapted from Hale Products, Inc.

5 Positive-Displacement Pumps (6 of 9) Adapted from Hale Products, Inc.

5 Positive-Displacement Pumps (7 of 9) Double-acting piston pump –Lets water flow more continuously using one piston –Still has periods of limited flow –Both valves at each end

5 Positive-Displacement Pumps (8 of 9) Rotary pumps are typically used as the priming pump for a centrifugal pump. –Discharge a constant flow of water with each revolution Rotary gear pump is typically used as a priming pump. –Driven by a 12-volt electric motor

5 Positive-Displacement Pumps (9 of 9) Rotary vane pump uses small moveable vanes to freely move in and out of rotor slots to maintain a tight seal against the pump casing. –Vanes automatically maneuver in and out to compensate for changes in the pump casing. –Centrifugal force keeps the vane tightly pressed against the pump casing, ensuring a tight seal.

5 Centrifugal Pump (1 of 11) Most common fire pump used today Replaced positive-displacement pumps on modern fire apparatus Water flow discharge is based on pressures at the discharge side of the pump. –At higher flow rates, the pump flows less volume but creates higher pressures.

5 Centrifugal Pump (2 of 11) Adapted from Hale Products, Inc.

5 Centrifugal Pump (3 of 11) Driver/operator needs to understand how the pump works to maximize its potential in firefighting operations. Pump operates on a principle of centrifugal force: the outward force from the center of rotation –The pump receives water into the center or eye of the impeller mounted inside the pump casing. –Impeller transfers energy from the vehicle’s motor to discharge incoming water

5 Centrifugal Pump (4 of 11) Centrifugal pump can pump only water or other liquids. –No valves from intake to discharge side –Not self-priming –Takes advantage of incoming pressure on the intake side to increase the discharge pressure Single-stage (one impeller) or multistage (two or more impellers within one pump housing turning on the same shaft)

5 Centrifugal Pump (5 of 11) A single-stage pump has one impeller that takes in and discharges water out of the pump. –A single impeller supplies 100 percent of the total water. –Simple to operate

5 Centrifugal Pump (6 of 11) Adapted from Hale Products, Inc.

5 Centrifugal Pump (7 of 11) Two-stage pump is the most common multistage pump –Two impellers enclosed in the pump casings –Each impeller is identical in size and capacity. –Transfer valve determines whether the pump will be operated in a series/pressure mode or parallel/volume mode

5 Centrifugal Pump (8 of 11) Parallel/volume mode: –Water enters each impeller and is discharged into a common discharge header. –Use when more than 50 percent of pump’s rated capacity needed Series/pressure mode: –Water travels through one impeller in the series. –Most common operating position for two-stage pumps Adapted from Hale Products, Inc.

5 Centrifugal Pump (9 of 11) Fire pump is rated by and tested to UL specs Pump must produce: –100% of rated capability at 150 psi (1034 kPa) for 20 minutes –70% of rated capability at 200 psi (1400 kPa) for 10 minutes –50% of rated capability at 250 psi (1723 kPa) for 10 minutes –No rating provided for pressures over 250 psi

5 Centrifugal Pump (10 of 11) Control valve on the pump panel of a multistage pump indicates whether impellers are operating in a parallel/volume or series/pressure mode Two-stage pump is similar to working from a hydrant water supply and pumper

5 Centrifugal Pump (11 of 11) Special multistage pumps are built to produce high pressures for special pumping requirements. Pump capacity has increased significantly with the development of larger pumps with larger impellers. –1950s: pumps delivered flows of 500 or 700 GPM (1892 or 2839 L/min) –Today: pumps can flow at GPM (7570+ L/min)

5 Power Supplies for Pumps (1 of 5) Driver/operator must know how pumps receive power. –Study schematics and manuals. Simplest form of power supply is available with the portable pump. –The pump is carried by two or more fire fighters to the water source. Some apparatus have a pump mounted on the front bumper.

5 Power Supplies for Pumps (2 of 5) Courtesy of Har-Rob Fire Apparatus, Inc.

5 Power Supplies for Pumps (3 of 5) Power take-off (PTO) units are used for small pumps like on tankers or tenders. –Provides a less-expensive method of developing pump power –Provide a pump-and-roll capability for certain apparatus A transfer case is the most common power system found in pumps. –Gearbox is mounted between transmission and rear axle

5 Power Supplies for Pumps (4 of 5) Adapted from Hale Products, Inc.

5 Power Supplies for Pumps (5 of 5) Pump speed is directly related to transmission speed –Transmission in first gear propels the pump at a slow pace. –Transmission in fifth gear turns it much faster. Automatic transmissions are made for pumping operations that will lock into the intended gear once the apparatus is in pumping mode.

5 Summary (1 of 2) The stainless steel pump panel is the most notable device on the apparatus. A driver/operator who understands the pump and its functions can operate with confidence. A pump is a mechanical device to move fluids; fire fighters want the pump to move water from a source to the fire through attack lines.

5 Summary (2 of 2) Fire service uses two types of pumps: positive-displacement pumps and centrifugal pumps. At higher flow rates (rpm) the pump flows less volume but creates higher pressures.