THEORY OF OPERATION - CONTINUED
WATER SPRAY SYSTEM
General. The water spray system is used to wet the front and rear drums to help prevent hot asphalt from sticking to the
drum surfaces during compaction. The water spray system consists of two identical, but separate systems, one at each
end of the roller. The water spray system uses pumps that provide pressurized water flow. Only one pump operates at a
time. The pumps are controlled by a switch on the operator console. This switch has three positions: off, continuous
spray and intermittent spray. The continuous spray setting turns on the water spray system and water sprays on the
drums continuously. The intermittent spray switch position uses fifteen-second on/off cycles of water spraying on the
drums to reduce water consumption. There are three draincocks that allow the water to be drained from the system. The
pumps pull water from two tanks and water spray screens which filter foreign material from the water. The water then
enters the pump and is pumped to the spray bar. There are seven spray nozzles in each spray bar which distribute the
water evenly over the surface of the drums. A check valve is located at the end of the spray bar to control the pressure of
the water in the spray bars. Excess water is sent past the check valve and back into the water tank. On the CB534B
Roller only, the front and rear water spray systems are connected by a tie-line valve, which allows one water spray sys-
tem to supply pressurized water to the nozzles of the other water spray system, in the event of failure of one of the
Water Spray Pumps. The water spray pumps are electrically activated positive displacement piston-type pumps that
operate on 24 Vdc. When activated, the pumps provide pressurized water flow to the water spray system.
Water Spray Screens. The water spray screens filter foreign matter from the water supply. There are two screens at the
water tank fill port and two in the water spray system.
Water Spray Tanks. The water spray tanks store water to be used in the water spray system. There is a screen on top of
the tank at the fill cap that acts as an initial filtering device at the tank.
Check Valves. A check valve is installed in each water tank at the end of each spray bar. The check valve regulates the
water pressure in the spray bar and allows excess water to flow back into the water tank.
Water Spray Bars. The spray bars distribute water to the spray nozzles. There are seven outlets on each spray bar
where the spray nozzles are attached. The spray bar is adjustable to change the coverage of water to the drums.
Water Spray Nozzles. The water spray nozzles spray water in a fan pattern onto the drums. The nozzles are made of
polyethylene and brass and contain a wire mesh screen to filter foreign material. There are fourteen nozzles and all are
Draincocks. The draincocks are directional valves that allow the water spray system to be drained. There are three
draincocks on the roller. One is located near each of the two water pumps and a third is located near the tie-line valve.
Tie-Line Valve. On the CB534B Roller, the tie-line valve is located in the center of the roller. The on/off valve allows
the front and rear water spray systems to interact. When this valve is open, one pump can send water to both the front
and rear spray bar and nozzles.
Drain Nipples. The drain nipples are located on the bottom of each water tank. Each tank can be completely drained by
removing the cap assembly from the nipple.
Shut Off Valves. On the CB534B Roller, shut off valves interrupt the flow of water from the water spray tank to the
water spray screen and spray pump. When turned off, water from the water tank cannot reach the rest of the system.
Water Spray Control Switches. On the CB534C Roller, the water spray control switches are toggle-type switches
mounted on the operator station. The intermittent/continuous switch controls the time interval that the system sprays the
water. Continuous mode sprays continuously, while the intermittent mode sprays water for fifteen seconds and stops for
fifteen seconds. The drum select switch sets whether the front, rear or both pumps are activated.