5 Pumper Apparatus Overview 5 Knowledge Objectives 1

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 positivedisplacement pumps and centrifugal pumps.

5 Knowledge Objectives (2 of 2) • Explain the different types of positivedisplacement pumps. • Explain the different types of centrifugal pumps. • Describe a single-stage pump and a twostage 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 Courtesy of Jim Hylton (4 of 4)

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 Adapted from Hale Products, Inc. (5 of 9)

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

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

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 • 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 of 11)

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

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 Adapted from Hale Products, Inc. • 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 k. Pa) for 20 minutes – 70% of rated capability at 200 psi (1400 k. Pa) for 10 minutes – 50% of rated capability at 250 psi (1723 k. Pa) for 10 minutes – No rating provided for pressures over 250 psi

5 Centrifugal Pump • 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 (10 of 11)

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. – 1950 s: pumps delivered flows of 500 or 700 GPM (1892 or 2839 L/min) – Today: pumps can flow at 2000+ 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 fighters to the water source. • Some apparatus have a pump mounted on the front bumper.

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

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 Adapted from Hale Products, Inc. (4 of 5)

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.