Measuring hammer operating pressure

MEASURING HAMMER CIRCUIT

MEASURING POINTS

FLOWMETER

HAMMER CONTROL VALVE OR MAIN VALVE BLOCK

p0 tank (with closed circuit from suction pipe of the pump). p2 straight before the restriction of the flow meter (e.g. Webster flow meter includes pressure gauge for p2) Q2 & T2 at flow meter, which connects pressure and return line of the hammer circuit. p3 straight after flow meter.

HOW TO MEASURE

Procedure for measuring and adjusting the hammer circuit. Note: Check and calibrate all the gauges you are going to use . Faulty pressure gauges should be changed. Note: If the flow to the hammer is adjusted by changing the engine revolutions, always check the flow also at full engine revolutions. Note: It is absolutely forbidden to use hammer above specified oil flow range. Warning : Don’t exceed the carrier’s main relief valve setting.

Check the lines, couplings, clamps etc. to ensure their condition. Replace worn or damaged components and tighten loose joints.

STEP 2

Check that there is a pressure relief valve in the hammer line.

STEP 3

Make sure that carrier’s hydraulic oil temperature is at normal operating level when measuring.

STEP 4

Connect the flowmeter in place of the hammer. It preferable to use same hoses and couplings that are used with the hammer, especially in cases when hoses are equipped with quick couplings.

STEP 5

Check that the adjustable restriction is open.

STEP 6

Start the engine and press the hammer operating switch.

STEP 7

Close the hammer line to adjust the crack point of pressure relief valve 50 bar (gauge p2) above the hammer max. operating pressure shown in the technical data.

STEP 8

Open the restriction so that the hammer’s operating pressure at gauge p2 is reached.

STEP 9

Check that the hammer’s oil flow is within the limits.

STEP 10

Check that the return line back pressure p3 doesn’t exceed the values allowed at the hammer oil flow.

STEP 11

Check that the hammer’s oil flow doesn’t increase when the carrier’s operating pressure exeeds the pressure in the hammer line (pressure compensated flow control). To do that , drive the boom, stick and bucket cylinders to the tilt position while pressing the hammer operating switch and checking the flow.

STEP 12

Open the restriction.

STEP 13

Stop the carrier engine.

STEP 14

Connect the hammer in place of the flow meter.

STEP 15

Measure hammer operating pressure. See "Measuring hammer operating pressure" on page 37.

STEP 16

When installing a new hammer check all the values after working about 50 hours with the hammer.