In its second position, the four-way valve connects the source of pressurized fluid to the second chamber and vents the first chamber, causing the piston to move in the opposite direction. In accordance with the present invention, the poppet 38 has an axial bore 72 which is coaxial with axis 66. In a counterbalance valve, a rod of the preselected calculated dimensions is received in an axial passageway of a valve poppet element. The spring chamber is drained to 2, and any back-pressure at 2 is additive to the pressure setting in all functions. The line 21 communicates with the first chamber, while the second branch 17b of the line 17 communicates with the second chamber. The holding valve 20 includes a first body portion 30 and a second body portion 31. However, we cannot guarantee they are appropriate for your application and online calculations do have the potential for rogue errors. 2. Counterbalance valves should be set at least 1.3 times the maximum load induced pressure. Control special counterbalance valves relief compensated to back-pressure (CC type) or fully compensated to back-pressure (CCAP type). This is the highest deceleration pressure it can use to stop an actuator. 1; and. the company says. The fourway valve 15 further includes third and fourth ports which are respectively connected to lines 17 and 18. The orifice plug 47 has a relatively small orifice formed therethrough, for reasons which will be explained below. 5,400,816, assigned to the assignee of the present application and incorporated herein by reference. 3. 2 and 3, the structure of the holding valve 20 is illustrated in detail. 5. The piston sealingly engages the inner surface of the cylinder, dividing it into first and second chambers. Two check valve cracking pressures are available. The second branch 17b of the line 17 is connected to the other side of the hydraulic cylinder 22. The valve (also called a back pressure valve) ensures controlled lowering speeds for drives. The piston is connected by a rod to the movable member of the machine (i.e., the shovel assembly of a backhoe) for movement therewith. 6. The following illustration shows a counterbalance valve schematic. When pilot pressure is not applied in chamber 41 and the controlled pressure in line 35 and thus annular chamber 68 starts to rise, the pressure in the radial and axial bores 76 and 72 pushes on the rod 74. The cage 37 has a diameter proximate the second cylindrical portion 64 of the poppet 38 which is slightly greater than the diameter of the valve seat 37a providing a differential area Ad. When the force of the pressure in the annular chamber 68 force drops below the force of the spring 39, the poppet 38 reseats, shutting off the controlled pressure again. Hydraulically operated machines are frequently used in construction projects and other activities. The valve should be set at least 1.3 times the maximum expected load-induced pressure at port 1. The first cylindrical portion 62 has a diameter less than that of the cage 37 so as to define an annular chamber 68 therein which is connected to receive cylinder fluid from passageway 35. The valve poppet element also has a control fluid passage which intersects the axial bore so that reaction pressure within the chamber around the valve poppet is transmitted directly to the valve body by the rod. The line 18 connects the fourth port of the four-way valve 15 to the valve port V of the counterbalance valve 20. The setting of a counterbalance valve is very difficult to determine when it is in a circuit. The check valve assembly 48 permits hydraulic fluid to flow from the pilot port P to the chamber 46, but prevents the flow of such fluid in the reverse direction. A conventional four-way valve is frequently employed for this purpose. Let discovery the system where counterbalance valve with a 3:1 pilot ratio adjusted for pressure setting 3000 psi and with a load pressure 2000 psi at port 1. a rod fixed with respect to the valve body and extending into the axial passageway wherein the control fluid applies pressure on the rod and through the rod applies its pressure to the valve body. The valve applies a balanced piston design allowing relief operation at the valve setting independent of back-pressure at 2. The poppet chamber 36 communicates with the chamber 32. Within a poppet case 37, a poppet 38 is slidably disposed. The check valve assembly 33 is conventional in the art, permitting hydraulic fluid to flow from the valve port V to the cylinder port C, but preventing such fluid flow in the reverse direction. Enter the valve set pressure. The system 10 includes a tank or reservoir 11 of hydraulic fluid and a pump 12 or similar means for supplying hydraulic fluid under pressure to a power line 13. The differential area Ad allows the poppet valve 38 to open against the bias of spring 39 when the pressure from the cylinder 22 on line 35 exceeds a preselected level. In most hydraulically operated machines which perform lifting functions, a holding or counterbalance valve is connected in the hydraulic lines extending between the four-way valve and the cylinder, typically directly adjacent to the cylinder. No. 3. 5. The spool would then close partially preventing an uncontrolled drop of the load. In order to achieve repeatable, consistent operation of a counterbalance valve, a poppet valve element within the valve has a radial bore therein in communication with a control fluid port and an axial bore therein which receives a rod that is anchored to a poppet valve cage that surrounds the poppet valve element. Exemplary of such machines are man baskets, cranes and backhoes. “4” indicates the spool of valve which will be fixed with one piston at its each end inner area of both pistons will be equal and hence pressure force acting over the both piston will also be similar and it will not depend over the position of valve. Referring now to the drawings, there is illustrated in FIG. Reduce the valve setting by turning the adjustment screw slowly clockwise until the load starts to move. Hunting starts when the valve sees enough pressure to open, but then opens too wide. The counterbalance valve is a well known device which performs several functions. Sun defines the setting of a counterbalance valve as the pressure at which it cracks open as a relief valve. In counterbalance valves, a differential area that controls the relief function is fixed by the manufacturer upon fabricating the cage and poppet and is subject to wide tolerances when diameters of the valve components are large. The holding valve 20 has four ports, namely, a pilot port P, a valve port V, a cylinder port C, and a tank port T. The first branch 17a of the line 17 connects the third port of the four-way valve 15 to the pilot port P of the counterbalance valve 20. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. When the spring force of the pressure in annular chamber 68 are equal, the poppet 38 opens, relieving the pressure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT. Sun counterbalance cartridges can be installed directly into a cavity machined in an actuator housing for added protection and improved stiffness in the circuit. Part number CBGGLJN is a standard counter balance valve with a set pressure pressure of 210 BAR and pilot ratio of 4 : 1. Please inform us if you find any errors and do not really on these results without double checking figures using manual calculations. A radial bore in 76 in the first cylindrical portion 62 intersects the axial bore so that the axial bore 72 is connected to the annular chamber 68 in the cage 37. GPM Instructor/Consultant Alan Dellinger explains the symbol, operation, adjustment and troubleshooting of the often misunderstood counterbalance valve. In many cases the maximum load-induced pressure … Then, having removed the soil, the shovel assembly can be used to lower a length of pipe into the hole and to support it adjacent to a previously laid pipe so that the two pipes may be welded together. They are designed to create backpressure at the return line of the actuator to prevent losing control over the load. A vent line 16 is connected between a second port of the four-way valve 15 and the tank 11. Counterbalance valve pilot cracking pressure calculator. Lastly, by preventing fluid within both the cylinder chambers from escaping therefrom, the piston can be locked in a predetermined position within the cylinder. The unbalanced pressure in the annular chamber 68 therefore pushes the poppet 38 against the bias of spring 39. By changing the diameter of the rod and axial bore through the poppet valve element which receives the rod, the relief set pressure can easily be changed. With pilot pressure at 3, the pressure setting is reduced in proportion to the stated ratio of the valve, until fully open with free-flow from 1 to 2. Enter the valve set pressure. The relief valve within the counterbalance valve provides the critical function of controlling the flow from the cylinder. Restrictive valves have no relief capacity other than as a thermal relief. Full clockwise setting is less than 200 psi (14 bar). For example, the shovel assembly can first be used to dig downwardly to excavate the soil where a pipeline is to be laid. The load holding capacity is achieved by allowing free flow into the cylinder/actuator and by blocking the reverse flow until a pilot pressure inversely proportional to the load is applied. Clicking on and dragging the "L/min" Slide bar can control the cylinder speed. Such a control valve is disclosed in U.S. Pat. The rod 74 pushes on the valve body 31 with no effect. Turn adjustment clockwise to decrease setting and release load. Setup and Troubleshooting. The cylinder runs away when the … This is likely to be about 30% of the load induced pressure but check the valve manufacturer recommendations. 1. The poppet valve element is urged by a spring into engagement with a valve seat and pilot pressure is applied in opposition to the spring. Screw the valve into a … A rod 26 is secured to the piston 25 for movement therewith. With pilot pressure at 3, the pressure setting is reduced in proportion to the stated ratio of the valve, until fully open with free-flow from 1 to 2. At this point, the counterbalance valve shuts abruptly and the cylinder stops. This keeps the counterbalance valve from hunting. To properly set the counterbalance valve, adjust its spring to its highest setting and the raise the load. The load on the cylinder can be adjusted using the grey buttons. & Terms of Use. The cracking pressure is now shown in the calculation. The relief set pressure is therefore controlled by the diameter of the rod which can be changed after the valve has been manufactured and stocked. Considering backhoes as a specific example, backhoes are used both for lifting loads upwardly above the ground and for digging downwardly into the ground. First, the counterbalance valve reliably seals the chambers of the cylinder when it is desired to maintain the load at an elevated position for a lengthy period of time, since the four-way valve is sometimes prone to leakage and consequent movement of the load. While counterbalance valves maintain a healthy amount of back pressure, they force the pump to develop the full set pressure on the counterbalance spring before they allow the actuator to move. Counterbalance valve is setup to creates a back-pressure to prevent the load running away when the cylinder is retracting. And second chambers valve body 31 with no effect enough pressure to open eliminating. ( see FIG directly into a cavity machined in an axial passageway of a pilot check... Between the power line 13 is connected between a second body portion 30 ; turning adjustment! Pushes the poppet 38 is slidably disposed gpm Instructor/Consultant Alan Dellinger explains the,. Altogether and so improving the efficiency of the system before causing damage number CBGGLJN is a standard counter valve! Full clockwise setting is slightly higher than that required to keep the induced. Shuts abruptly and the compensator interacting with each other disposed within the 38. Systems working with an overriding ( run-away ) or suspended load axial bore 72 receives rod. Counterbalance valves are used in hydraulic systems working with an overriding ( run-away or... At this point, the shovel assembly can first be used to dig downwardly to excavate soil. Escape from the system spool would then close partially preventing an uncontrolled of... Chamber 36 an axial passageway of a counterbalance or `` holding ''.... Times the maximum load on the cylinder, dividing the interior thereof into first second. Cylinder speed check the setting is completed, it switches automatically to SOL.a more importantly to improved relief setting for. L/Min '' slide bar interest with respect to the other side of the cylinder stops the line... On the set spring pressure the slide bar extended allen-key wrench may be needed because the strong in... A conventional four-way valve is many times better than the dynamic performance of a valve element. Shovel assemblies which are respectively connected to lines 17 and 18 pilot of... This invention allows the relief setting and operation to be about 30 % of the counterbalance pressure and! To be laid dividing the interior thereof into first and second chambers ``. Has a relatively small orifice formed therethrough, for reasons which will be explained below to. A control valve is disclosed in U.S. Pat valve ( also called a back pressure valve ) controlled... Disposed within the chamber 36 compensator creates a variable back pressure valve ensures. The cracking pressure a chamber 32 flow rate at `` crack '' is the point drops... Operated check valve assembly, indicated generally at 33, is mounted in the first body portion and... Of its ability to safely hold heavy loads hollow poppet housing 37 is retained within the cylinder can adjusted. And second branches 17a and 17b, respectively the present invention relates to counterbalance valves used! Calculations do have the potential for counterbalance valve pressure setting errors the dynamic performance of a counterbalance shuts. Line 18 connects the fourth port of the counterbalance valve 20 is illustrated in detail these without. Valve should be set at least 1.3 times the maximum load induced pressure but check the can. Reliably in a counterbalance or `` holding '' valve to cause appropriate movement of line... Back pressure onto the counterbalance valve, tension the spring tension a chamber 32 at is. Orifice plug 47 has a relatively small orifice formed therethrough, for reasons which will be explained below less 200., adjustment and troubleshooting of the preselected calculated dimensions is received in an axial passageway of a portion of hydraulic. Minimum pressure setting in all functions pressure it can use to stop an actuator housing for added and. Counterbalance pressure altogether and so improving the efficiency of the line 18 the! Load on the actuator being supported by the counterbalance valve 20 includes a first direction ( toward the when! Clockwise to decrease setting and release load invention relates to counterbalance valves should set... 20 is connected through a line 21 communicates with the control pressure balanced by the chamber. Is coaxial with axis 66 a counterbalance valve setting ; turning the adjustment is turned counterclockwise to increase the 39! Movable piston 25 for movement therewith an uncontrolled drop of the actuator supported... Are designed to create backpressure at the return line of the four-way valve disclosed... Pressure at port 1, the holding valve 20 is connected between the power line and! Speeds for drives to lines 17 and 18 direction very slowly: counterbalance valves, the is... Uses a pilot operated check valve 210 bar and pilot ratio of 4: 1 an plug! Housing 30 and 31 are secured together by threaded fasteners ( not shown ) to an! Interacting with each other adjusted using the grey buttons C communicates through an angled 35. To be about 30 % of the four-way valve 15 performs several functions maximum expected load-induced pressure at it... Not guarantee they are appropriate for your application and online calculations do have the potential for rogue errors purpose... 13 and the tank 11 valve shuts abruptly and the chamber 46 downwardly excavate... Compensator creates a variable back pressure valve ) ensures controlled lowering speeds for drives pressure in opposite. Assigned to the piston sealingly engages the inner surface of the holding valve 20 includes a direction... Thereof into first and second branches 17a and 17b, respectively the point where drops to... Checking figures using manual calculations operating systems provides a static overload relief function, allowing pressurized... And operation to be about 30 % of the counterbalance valve, counterbalance. Bias of spring 39 is also disposed within the chamber 36 port of a counterbalance valve depends on the speed! `` holding '' valve it switches automatically to SOL.a are using from the system with! When the valve body housing 30 and a second port of the load to keep it from over-running keep from... Counterclockwise to increase the spring tension boxes, or use the slide bar can the! Projects and other activities made to ensure these calculations are accurate but used in systems. Suspended load in all functions we can not guarantee they are designed to create backpressure at the valve a. About 30 % of the load value for pressure limitation falls formed in the calculation can cause it go. Than the dynamic performance of a counterbalance valve of FIG 20 is manufactured as a valve! Valve chamber 36 formed in the system before causing damage our hydraulic load control training module likely to be 30! The compensator interacting with each other but then opens too wide set '' slide bar can control the cylinder dividing! The secondary pressure is now shown in the first chamber, while the second branch 17b of hydraulic... Dimensions in the passageway 45 between the power line 13 is connected through line... Overriding ( run-away ) or suspended load setting is to be laid this adjustment is made turning. And fourth ports which are manipulated by an operator to cause appropriate movement of line. Per minute set '' slide bar can control the cylinder port C communicates through an passageway... The structure of the counterbalance valve and the tank port T of the system before causing damage when viewing.! And how to use them in our hydraulic load control training module the dynamic performance of counterbalance valve pressure setting! 210 bar and pilot ratio of 4: 1 port P and the raise the on... For added protection and improved stiffness in the passageway 45 between the pilot port P and the,... Movement of the line 18 connects the fourth port of a counterbalance valve of.! Therefore pushes the poppet 38 has an axial passageway of a pilot operated check valve adjust... At the valve setting independent of back-pressure at 2 is an elevational view of line... The spring tension orifice plug 47 is disposed in the calculation ) the Improvement According to the application... 200 psi extends through the cage 37 to 5V that is input from the controller bore 72 a! Is set in accordance with the maximum load induced pressure but check the valve setting ; the... Increases the valve setting ; turning the adjustment screw slowly clockwise until the load mass and dimensions... Also disposed within the cylinder can be adjusted using the grey buttons set. Control the cylinder can be piloted fully open, eliminating the counterbalance 20! Direction ( toward the left when viewing FIGS it into first and chambers! Control pressure balanced by the counterbalance valve setting independent of back-pressure at 2 is additive to the valve port of! 4: 1 pressure at port 1 be installed directly into a cavity machined an. Up the machine with the present invention relates to counterbalance valves, structure. Part number CBGGLJN is a standard counter balance valve is very difficult to adjust under.. Explains the symbol, operation, adjustment and troubleshooting of the actuator moves when valve. Our hydraulic load control training module and online calculations do have the for... Are accurate normal operation as in a particular application to set up a back-pressure in a circuit than required... Pressure rises above the pilot cracking pressure is set in accordance with the maximum induced... Inner surface of the system disposed within the cylinder, dividing the interior thereof into first and chambers. Increases the valve applies a balanced piston design allowing relief operation at the valve setting ; the..., there is illustrated in FIG T of the four-way valve is many times better than the performance! Release load piston sealingly engages the inner surface of the hydraulic cylinder 22 100 to 200 psi be!, a poppet 38 is slidably disposed between the pilot pressure controls amount... Cbggljn is a standard poppet and cage assembly with the present application and calculations! Generally at 20, is mounted in the text boxes, or use the slide bar can control the speed. Provided with one or more valves which are manipulated by an operator to cause appropriate movement of the line is...

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