Hand-Operated Hydraulic Pump

Transcription

1 m be certain. Hand-Operated Hydraulic Pump Product Information A

2 Copyright information Trademark information 2014 MTS Systems Corporation. All rights reserved. MTS is a registered trademark of MTS Systems Corporation within the United States. This trademark may be protected in other countries. All other trademarks or service marks are property of their respective owners. Publication information Manual Part Number Publication Date A August 2014

3 Contents Install the Hand-Operated Hydraulic Pump 5 Determine the Gripping Pressure 7 Install Specimen in the Grips 10 Remove Specimen from the Grips 10 Maintenance 11 Hand-Operated Hydraulic Pump 3

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5 Hand-Operated Hydraulic Pump Install the Hand-Operated Hydraulic Pump A hand-operated hydraulic pump kit (MTS part number ) is an accessory for operating the grips. The kit includes the pump, with shut-off and release valves, a pressure gage, and hydraulic hoses for connecting the pump to the grips. The kit also contains an extra supply of hydraulic fluid. An appropriate grip supply with good pressure stability is required to safely operate hydraulic grips. The pump can be mounted to the base of the load frame with the provided brackets and magnets. If you have a load frame that does not accommodate base mounting, the hand pump can be placed on the floor near the load frame. It includes two hydraulic hoses; one is 1829 mm (72 in) long; and the other is 2286 mm (90 in.) long. Typical Grip Installation The hand pump is provided with a plate including the hardware to mount the hand pump to the side of any MTS Landmark load frame. When space permits, the hand-operated hydraulic pump can be mounted to the sheet metal base of the load unit. If not, other mounting arrangements will need to be devised. As a minimum, mount the pump on a board or on an adjacent tabletop. Hand-Operated Hydraulic Pump 5

6 Note In order for the pump to operate, the reservoir end of the pump assembly must be higher than the output end (or at least the same elevation). 1. Mount the pump. The preferred location is on the base of the load unit. If you are using the hand pump with a Landmark Load frame, follow the instructions below to mount the hand pump. A. Lift the rubber work surface and remove the two screws holding down the metal work surface of the load frame (A). B. Stick the rubber tape to the corner of the load frame base to protect the paint from the hand pump. C. Put the hand pump on the side of the load frame using the magnets. Position the pump so the holes in the mounting bracket align with the holes in the metal work surface. D. Re-install the screws to clamp the hand pump and metal work surface. E. Put the rubber work surface back into place. 2. Connect the hydraulics. The hydraulic source to operate the grips is from a hand-operated hydraulic pump.the hand pump should be installed on your load frame. A. Using the provided hydraulic hoses, make connections between the pressure ports on each grip and the ports on the hand-operated hydraulic pump. B. Connect hoses between the pump and the grips. Tighten both of the hoses at the pump end. At the grip ends, leave the hoses connected, but loose. C. With the hoses loose at the grip ends, close the pump s pressure release valve and actuate the pump until all air is expelled from the hoses, and then tighten the hose fittings at the grips. 6 Hand-Operated Hydraulic Pump

7 Determine the Gripping Pressure D. Apply sufficient pressure to the grips and check for leaks at all fittings. Sufficient pressure will be determined by the gripping force specifications of the grip. E. After ensuring that all connections are leak free, open the pressure release valve to release the pressure in the grips. With the reservoir end of the pump pointed up, fill the reservoir with Quaker Quintolubric hydraulic fluid, or equivalent. If the level is ever low, add more hydraulic fluid. Improper grip pressure can damage the grips and cause possible personal injury. Insufficient grip pressure can result in specimen slippage or wedge movement which can damage the grips. Using a grip pressure that exceeds the pressure rating of the grip can result in damage to the grips. For hydraulic grips and fixtures, make sure that the hydraulic supply pressure is limited to the maximum pressure defined by the grip or fixture identification (ID) tag. The amount of hydraulic pressure to be applied to the grips must be sufficient to prevent backlash between the specimen ends and the specimen adapters, and also between the mating threads of the specimen adapters and the grip extensions, during all parts of the loading cycle. To also ensure that the grips will not be loaded beyond their force rating, however, determining hydraulic pressure must start with temperature considerations, rather than the forces to be applied to the specimen. Note If the gripped ends of the specimen become deformed, reduce the hydraulic gripping pressure. Re-compute the amount of pressure required to grip the specimen. Determining the required hydraulic pressure is a two step process: 1. Determine that the maximum force (whether tensile or compressive) to be applied to the specimen is within the grip rating, considering the temperatures that the specimen will experience. 2. If anticipated forces are appropriate, use the Required Pressure for the Applied Force graph to find the required gripping pressure. Hand-Operated Hydraulic Pump 7

8 Force versus temperature The following figure shows that the grip force rating for specimen temperatures up to 700 C is 67 kn (1292 F at 15,000 lb) is stable. The figure also shows that the force rating is reduced proportionately for specimen temperatures between 700 C and 1000 C (1292 F and 1832 F), with a maximum force rating of 8.9 kn at 1000 C (2000 lb at 1832 F) kn (15 kip) Load 66.7 kn up to 700º C (15 kip up to 1292º F) 8.9 kn at 1000º C (2 kip at 1832º F) 0 kn (0 kip) 482º C (900º F) Specimen Temperature 1038º C (1900º F) Grip Force Rating versus Specimen Temperature Force versus hydraulic pressure The horizontal scale at the bottom of the graph shows required gripping pressure versus maximum force to be applied, which is shown on the left hand vertical scale. The right hand vertical scale is provided as a convenience. Assuming that the gage portion of the specimen has a diameter of 0.25 inches, the right hand scale shows maximum engineering stress (for a 0.25 inch diameter specimen), versus required gripping pressure on the bottom horizontal scale and also the equivalent force on the left hand vertical scale. 8 Hand-Operated Hydraulic Pump

9 Required Pressure for the Applied Force Hand-Operated Hydraulic Pump 9

10 Install Specimen in the Grips Perform the following procedure to mount a specimen in the grips. Ensure that all grip parts are sufficiently cool before touching them. WARNING Specimen mounting is a potentially hazardous procedure because hydraulic pressure is applied to the system and actuator movement is required. This can cause personal injury. It can also apply damaging forces to the specimen, furnace, or to other fixtures. Use extreme care while performing the following steps. Always use your load frame s low velocity control (if equipped). Remove Specimen from the Grips 1. Determine the hydraulic pressure that must be applied to the grips in order to adequately grip the specimen. 2. Install the specimen using the procedure provided in the specific grip product manual. 3. When satisfied that the specimen is properly installed, actuate the handoperated pump until the required hydraulic pressure is shown on the pressure gage. 1. Turn the hydraulic hand pump pressure release valve counterclockwise until the pressure indicated on the pressure gage reads zero. This allows either the grip piston or wedge springs to release the specimen. 2. Remove the specimen using the procedure provided in the specific grip product manual. 10 Hand-Operated Hydraulic Pump

11 Maintenance Maintenance for the hydraulic hand pump involves checking the fluid level in the reservoir of the hand pump occasionally by removing the pump s reservoir plug and observing the level shown on the dip stick. If the level is low, add Quaker Quintolubric hydraulic fluid, or equivalent, only. Difficulty in obtaining or maintaining the pressure required for grip operation can be caused by low fluid level. Location of Reservoir Plug Hand-Operated Hydraulic Pump 11

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