Copyright Goodheart-Willcox Co., Inc. Chapter 8 Fluid Storage and Distribution 183 to prevent dirt and water from entering the tank through the opening while absorbing normal pump and power unit vibration. See Figure 8-3. The pickup end of the inlet line should be positioned well below the normal The typical hydraulic system reservoir is a rect- angular, covered tank made from welded or formed steel plate. The tank is often fi tted with short legs to permit circulation of air for cooling of the bottom sur- face. Also, the bottom of the tank is often dished and includes a drain hole to allow easy drainage. The ends, sides, or top of the tank are often fi tted with ports with removable covers to permit easy cleaning. The tank is also fi tted with a vented breather that allows the tank to take in and release air as the fl uid level changes dur- ing system operation. In many systems, the breather is incorporated into the fi ller cap. An especially important part of the construction of a reservoir is the baffl e. A baffl e separates the pump inlet and system return lines. This baffl e is often noth- ing more than a vertically positioned, fl at plate that divides the tank lengthwise. See Figure 8-2. The baffl e prevents the warm hydraulic oil from moving directly from the return line to the pump inlet. Forcing the oil to travel around the baffl e provides longer contact with the sides of the tank. This allows better cooling as well as a longer time for separation of air and the settling of dirt and water. The reservoir is fi tted with three lines connected to the system. These are the pump inlet line, system return line, and a drain return line. The inlet line provides fl uid to the pump. The inlet line should be large enough to provide fl uid at a veloc- ity and pressure drop lower than that suggested by the pump manufacturer. The hole where the inlet line enters the reservoir should be fi tted with a packed- slip joint Pump inlet line Filler/breather System return line Strainer Baffle Goodheart-Willcox Publisher Figure 8-2. Baffles are used inside reservoirs to direct the flow of hydraulic fluid. They control fluid movement in the tank to promote fluid cooling and cleaning. Pump inlet line Drain line Return line Return line end: 1. Cut at 45° angle 2. Two pipe diameters from bottom of reservoir 3. Directs fluid flow along reservoir sides Reservoir baffle Fluid level Packed-slip joint Inlet line end: 1. Minimum of 1″ from reservoir bottom 2. May be fitted with a sump strainer Goodheart-Willcox Publisher Figure 8-3. Pump inlet, return, and drain return lines must be carefully positioned in a reservoir. The distance from the ends of these lines to the bottom of the reservoir will affect system performance.