An orifice plug 47 is disposed in the passageway 45 between the pilot port P and the chamber 46. The rod 74 pushes on the valve body 31 with no effect. 1. A counterbalance valve’s function is to maintain a set pressure against the load to keep it from over-running. Privacy Policy 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. Adjust the supply pressure to see that the actuator moves when the supply pressure rises above the pilot cracking pressure. Within a poppet case 37, a poppet 38 is slidably disposed. 2 is an elevational view of the counterbalance valve illustrated in FIG. Clicking on and dragging the "L/min" Slide bar can control the cylinder speed. This is the highest deceleration pressure it can use to stop an actuator. 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. This is due to cross-piloting, load-induced pressure, and cylinder ratio. A check valve assembly, indicated generally at 33, is mounted in the chamber 32. 6. In accordance with the present invention, the poppet 38 has an axial bore 72 which is coaxial with axis 66. 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. These normally closed valves are primarily used to maintain a set pressure in part of a circuit, usually to counterbalance a weight or external force or counteract a weight such as a platen or a press and keep it from free-falling. 3. Screw the valve into a … 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. In a counterbalance valve, a rod of the preselected calculated dimensions is received in an axial passageway of a valve poppet element. 3 position valve (VEX3222-5M) When the start signal is input to the controller, it switches automatically to SOL.b and through the throttle valve prevents the cylinder from quick extensions. Since the differential area Ad is determined during manufacture, it cannot be changed for a given valve in order to control system pressure oscillations. 2. 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. Second, the holding valve carefully modulates the rate at which hydraulic fluid flows from cylinder chambers, thereby regulating the speed at which a heavy load is lowered. In the counterbalance mode, the pilot pressure in chamber 41 acts all of the time against the bias of spring 39 only and not against the controlled pressure, thus providing repeatable, consistent operation regardless of the controlled pressure. If pilot pressure is set too low, the counterbalance valve may quickly open too far — allowing the cylinder to run away and pilot pressure to drop. The relief valve opens when the combined force created by the pilot pressure and the load-induced pressure exceeds the relief setting (typically 1.3 times the maximum load pressure). By changing the diameter of the rod 74 and the bore 72 to accommodate the rod, the relief set pressure can be changed so that the effects of the relief function on the pilot pressure are minimized resulting in more repeatable, consistent counterbalance operation of the counterbalance valve 20. GPM Instructor/Consultant Alan Dellinger explains the symbol, operation, adjustment and troubleshooting of the often misunderstood counterbalance valve. Select the type of actuator you are using from the drop-down list. 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. The hydraulic operating systems of backhoes and similar machines typically include a source of pressurized fluid which is selectively connected to a cylinder containing a movable piston. 2. 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 rising pilot pressure on X, the setting value for pressure limitation falls. Indeed the valve can be piloted fully open, eliminating the counterbalance pressure altogether and so improving the efficiency of the system. Counterbalance valve pilot cracking pressure calculator. Such systems are provided with one or more valves which are manipulated by an operator to cause appropriate movement of the shovel assembly. The valve’s primary port is connected to the cylinder’s rod end, and the secondary port to the directional control valve (Fig. 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. 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. The load on the cylinder can be adjusted using the grey buttons. The cylinder port C of the counterbalance valve 20 is connected through a line 21 to one side of a hydraulic cylinder 22. Control special counterbalance valves relief compensated to back-pressure (CC type) or fully compensated to back-pressure (CCAP type). During normal operation, the pilot pressure on line 40 in chamber 41 controls the amount that the poppet valve 38 opens against the bias of coil spring 39. When the setting is completed, it switches automatically to SOL.a. The valve port V communicates with the cylinder port C through a chamber 32 formed in the first body portion 30. pilot pressure, required to open the relief valve is 333 psi, i.e: [set.pressure 3000 psi] = [load pressure 2000 psi] … Most applications where pressure compensated proportional valves are used involve metering out of the actuator down stream of the counterbalance valve. This keeps the counterbalance valve from hunting. 3. Considering backhoes as a specific example, backhoes are used both for lifting loads upwardly above the ground and for digging downwardly into the ground. A check valve assembly, indicated generally at 48, is disposed in the passageway 45 between the orifice plug 47 and the chamber 46. L oosen the jam nut. 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 counterbalance valve assembly of claim 1, wherein the poppet valve assembly includes a slidable poppet valve element therein, and wherein the passage is through the poppet valve element, the assembly further including a rod fixed to the valve body and extending through the passage wherein the fluid pressure from the fluid actuator is applied through the rod to the body. For example, the valve could be required to be set at 200 bar (3,000 psi) with a counterbalance pressure between 35 and 70 bar (500 to 1,000 psi). Counterbalance valves should be set at least 1.3 times the maximum load induced pressure. Figure shows the internal construction of counterbalance valve. Full clockwise setting is less than 200 psi (14 bar). Please inform us if you find any errors and do not really on these results without double checking figures using manual calculations. Thus, fluid is prevented from flowing around the check valve assembly 33 from the cylinder port C to the valve port V. Therefore, so long as the poppet 38 remains seated on the seat 37a of the poppet case 37, no hydraulic fluid is permitted to flow from the cylinder port C to the valve port V. The pilot port P communicates through a passageway 45 with an internal chamber 46 formed in the second body portion 31 of the holding valve 20. 3 is an elevational view of a portion of the counterbalance valve of FIG. To properly set the counterbalance valve, adjust its spring to its highest setting and the raise the load. Two check valve cracking pressures are available. The two-stage valve has overcome many instability problems by preventing the total decay of the stored energy in the cylinder and stopping the valve overreacting. 5,400,816, assigned to the assignee of the present application and incorporated herein by reference. The cylinder port C communicates through an angled passageway 35 with a poppet valve chamber 36 formed in the first body portion 30. A spring 39 is also disposed within the poppet case 37. However, we cannot guarantee they are appropriate for your application and online calculations do have the potential for rogue errors. In this case, the min. In many cases the maximum load … 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. 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. As is best seen in FIG. This is likely to be about 30% of the load induced pressure but check the valve manufacturer recommendations. 2 and 3, the structure of the holding valve 20 is illustrated in detail. © 2004-2021 FreePatentsOnline.com. 91/420, 91/447, 137/106, 251/25, 137/106, 137/269, 137/599, 91/420, 91/447, 251/25, 251/30.03, MILLEN WHITE ZELANO & BRANIGAN (ARLINGTON, VA, US), Click for automatic bibliography 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. An extended allen-key wrench may be needed because the strong springs in the valve make them difficult to adjust under pressure. Turning the adjuster counterclockwise increases the valve setting; turning the adjustment clockwise lowers the pres-sure setting, releasing the load. Counterbalance valve stops flow from its inlet port to its outlet port until pressu… 1. It allows the pressure to fall to the counterbalance setting, … 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. 3:1 is probably a good place to start. 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. The present invention relates to counterbalance valves and more importantly to improved relief setting arrangements for counterbalance valves. 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. Enter the load mass and actuator dimensions in the text boxes, or use the slide bar. Enter the valve set pressure. This is the highest deceleration pressure it can use to stop an actuator. Counterbalance valves are also known as load holding valves because of its ability to safely hold heavy loads. The piston sealingly engages the inner surface of the cylinder, dividing it into first and second chambers. A vent line 16 is connected between a second port of the four-way valve 15 and the tank 11. Counterbalance valves should be set at least 1.3 times the maximum load induced pressure. For very low flow, a counterbalance valve can also serve as a thermal relief valve. The cracking pressure is now shown in the calculation. The line 21 communicates with the first chamber, while the second branch 17b of the line 17 communicates with the second chamber. Set up the machine with the maximum load on the actuator being supported by the counterbalance valve. The following illustration shows a counterbalance valve schematic. Exemplary of such machines are man baskets, cranes and backhoes. Sun counterbalance cartridges can be installed directly into a cavity machined in an actuator housing for added protection and improved stiffness in the circuit. Setup and Troubleshooting. Counterbalance valve. The second branch 17b of the line 17 is connected to the other side of the hydraulic cylinder 22. The fourway valve 15 further includes third and fourth ports which are respectively connected to lines 17 and 18. 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. a passage in the poppet valve assembly for applying fluid pressure from the fluid actuator to the valve body whereby the pilot fluid applies pressure only against the bias of the spring. The valve applies a balanced piston design allowing relief operation at the valve setting independent of back-pressure at 2. Sun defines the setting of a counterbalance valve as the pressure at which it cracks open as a relief valve. The 3:1 area ratio of the counterbalance valve spool means only 100 psi of pilot pressure is needed to open the valve. generation, Pilot actuated override mechanism for holding valve, Poppet configuration for counterbalance valve, Integral hydraulic blocking and relief valve. Part number CBGGLJN is a standard counter balance valve with a set pressure pressure of 210 BAR and pilot ratio of 4 : 1. Read more about counterbalance valves and how to use them in our hydraulic load control training module. Enter the valve set pressure. This is likely to be about 30% of the load induced pressure but check the valve manufacturer recommendations. The spring 39 urges the poppet 38 in a first direction (toward the left when viewing FIGS. A movable piston 25 is disposed within the cylinder 22, dividing the interior thereof into first and second chambers. The best way to check the setting is to remove the valve from the circuit. 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. pressure at 1 rises above the pressure setting (turn counterclockwise to increase setting - turn clockwise to decrease setting), the direct-acting, differential area relief function is activated and flow is relieved from 1 to 2. However, a hollow poppet housing 37 is retained within the chamber 36. The rod 26 is connected to a movable member, such as the lifting arm of a crane or man basket or the shovel assembly of a backhoe or similar machine, and extends outwardly from the cylinder 22. Referring now to FIG. 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. The cylinder runs away when the … 6). Reduce the valve setting by turning the adjustment screw slowly clockwise until the load starts to move. a primary check valve assembly for permitting fluid to flow in a first direction from the valve port to the cylinder port of the counterbalancing valve assembly; a poppet valve assembly for permitting fluid to flow in a second direction from the cylinder port to the valve port of the holding valve assembly, said poppet valve assembly being biased by a spring to a closed position for preventing fluid from flowing therethrough, an open position for permitting fluid to flow therethrough, and intermediate positions for modulating the rate at which fluid flows therethrough, the selection of which being determined by pilot fluid pressure communicated through a first passage in the counterbalance valve assembly from the valve pilot port to said poppet valve assembly; and. Two-stage valves are an efficient solution to fix these challenges by reducing sudden instability or chatter at the beginning of a cylinder’s movement with an initial counterbalance pressure. The line 18 connects the fourth port of the four-way valve 15 to the valve port V of the counterbalance valve 20. Such a control valve is disclosed in U.S. Pat. This invention allows the relief setting and operation to be controlled accurately and reliably in a counterbalance or "holding" valve. A rod 26 is secured to the piston 25 for movement therewith. The power line 13 is connected to a first port of a conventional four-way control valve 15. 1; and. 2) The Improvement According to the Present Invention. The cracking pressure is now shown in the calculation. the company says. 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. Hunting starts when the valve sees enough pressure to open, but then opens too wide. 3. The axial bore 72 receives a rod 74 which is fixed to the valve body housing 30 and extends through the cage 37. On many counterbalance valves, this adjustment is made by turning counterclockwise to increase the spring force. 1 a schematic diagram of a hydraulic operating system, indicated generally at 10, such as might be used for operating apparatus such as man baskets, cranes, backhoes and other derives such as devices used on utility vehicles. Conversely, by connecting the source to the second chamber and by venting the first chamber, the piston can be moved in the opposite direction relative to the cylinder. Restrictive valves have no relief capacity other than as a thermal relief. FIG. Other aspects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. Referring now to the drawings, there is illustrated in FIG. The line 17 includes first and second branches 17a and 17b, respectively. Every attempt has been made to ensure these calculations are accurate. 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. The orifice plug 47 has a relatively small orifice formed therethrough, for reasons which will be explained below. In its third position, the four-way valve prevents fluid within both of the chambers from escaping therefrom, causing the piston to be locked in a predetermined position. 3) formed on the poppet case 37. The valve (also called a back pressure valve) ensures controlled lowering speeds for drives. They are employed when it is necessary to relief pressure at the pre-established pressure setting (Pt), without over-pressurizing the system, independently from any back-pressure in the return line. For example, the shovel assembly can first be used to dig downwardly to excavate the soil where a pipeline is to be laid. The pilot pressure controls the amount of poppet opening against the bias of spring 39 during normal operation as in a standard counterbalance valve. The tank port T of the holding valve 20 is connected through a line 23 to the tank 11. The outlet pressure is normally connected to tank but backpressure can be added by clicking on and dragging the " pressure T" slide bar. To properly set the valve, tension the spring to its highest setting and the raise the load. & Terms of Use. The pilot port P, the valve port V, the cylinder port C, and the tank port T are all formed in the first body portion 30, and the lines 17a, 18, 21 and 23 are respectively connected thereto. 6. The holding valve 20 includes a first body portion 30 and a second body portion 31. & Terms of Use. The poppet chamber 36 communicates with the chamber 32. In many cases the maximum load-induced pressure … 5. They are designed to create backpressure at the return line of the actuator to prevent losing control over the load. Technical … The valve applies a balanced piston design allowing relief operation at the valve setting independent of back-pressure at 2. To accomplish this, backhoes are provided with articulated shovel assemblies which are moved by hydraulic operating systems. When the spring force of the pressure in annular chamber 68 are equal, the poppet 38 opens, relieving the pressure. The pilot pressure at Z, required to open the valve in case of an unloaded cylinder depends on the valve pilot ratio R and the pressure setting of the spring. These are basically relief valves but used in a particular application to set up a back-pressure in a circuit. The valve should be set at least 1.3 times the maximum expected load-induced pressure at port 1. As is well known, by connecting the source to supply pressurized fluid to the first chamber and by simultaneously venting the second chamber, the piston can be moved in one direction relative to the cylinder. The spool would then close partially preventing an uncontrolled drop of the load. 4. The setting of a counterbalance valve is very difficult to determine when it is in a circuit. - the opening pressure of a counterbalance valve depends on the set spring pressure. Since the counterbalance pilot pressure depends on the relief pressure setting, the existing relief function set by the manufacturer interferes with pilot operation of the counterbalance function and relief action cannot be controlled or dampened to avoid system pressure oscillations. 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. If this occurs, the holding valve prevents any hydraulic fluid from flowing in or out of the cylinder chambers, thereby locking the piston within the cylinder and preventing the load from falling. On most externally piloted counterbalance valves, the minimum pressure setting is 100 to 200 psi. Consequently, the pressure in annular chamber 68 is always applied to the valve body 30 via the rod 74 since the rod 74 is within the bore 72 that is always in communication with the annular chamber 68 via the radial bore 76. The counterbalance valve is a well known device which performs several functions. “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. 2. Lastly, by preventing fluid within both the cylinder chambers from escaping therefrom, the piston can be locked in a predetermined position within the cylinder. At this point, the counterbalance valve shuts abruptly and the cylinder stops. Before removing any valve, ensure machines and loads are mechanically held in position and that the valve is not under pressure at the time of its removal. Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: FIG. Fourth, and perhaps most importantly, the holding valve prevents the load from dropping uncontrollably if there is a break in one of the lines connecting the source of pressurized fluid to the cylinder. 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. 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. Select your pilot ratio. On many counterbalance valves, the adjustment is turned counterclockwise to increase the spring tension. pressure setting: Counterbalance valves adjust in the opposite direc-tion of other pressure con-trol valves. 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. Hydraulically operated machines are frequently used in construction projects and other activities. pressure at 1 rises above the pressure setting (turn counterclockwise to increase setting - turn clockwise to decrease setting), the direct-acting, relief function is activated and flow is relieved from 1 to 2. 3, where a portion of the counterbalancing valve 20 is shown in isolation, it is seen that the poppet 38 has a frustoconical portion 60 which converges into a first cylindrical portion 62 and a second cylindrical portion 64 which has an outer diameter corresponding to the inner diameter of the cage 37 so as to stabilize the poppet in the cage when the poppet opens in the direction of axis 66. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT. 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. 6. In order to control the flow of pressurized fluid to and from the cylinder chambers, a control valve is usually connected between the source of pressurized fluid and the cylinder chambers. The relief valve within the counterbalance valve provides the critical function of controlling the flow from the cylinder. 2 illustrating features of specific interest with respect to the present invention. In its first position, the four-way valve connects the source of pressurized fluid to the first chamber and vents the second chamber, causing the piston to move in one direction. All rights reserved. The spring chamber is drained to 2, and any back-pressure at 2 is additive to the pressure setting in all functions. The body portions 30 and 31 are secured together by threaded fasteners (not shown) to form an integral valve body. When the poppet 38 engages the seat 37a under the urging of the spring 39, fluid communication is prevented between the chamber 36 and the chamber 32. 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. 1 is a schematic diagram of a hydraulic operating system for a machine having a movable member adapted to perform various functions, the system including an improved counterbalance valve in accordance with this invention; FIG. 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. Next, very slowly turn the adjustment in the … As is well known in the art, the four-way valve 15 is selectively moved so as to cause the piston 25 to move relative to the cylinder 22, thereby moving the member connected to the rod 26. Are equal, the holding valve 20 is connected between the power line 13 connected! Branch 17b of the line 17 communicates with the cylinder port C through a line 23 to valve... Form an integral valve body housing 30 and extends through the cage 37 point where drops to!, while the second branch 17b of the pressure at which it cracks open as a valve. To create backpressure at the return line of the holding valve provides a overload! Body housing 30 and extends through the cage 37, for reasons which will be explained.... Piloted fully open, eliminating the counterbalance valve, tension the spring chamber drained! 39 urges the poppet 38 opens, relieving the pressure in annular chamber 68 equal! The type of actuator you are using from the circuit which are manipulated an! Ability to safely hold heavy loads of such machines are man baskets, and. Counterbalance pressure altogether and so improving the efficiency of the cylinder, to assist in opening a poppet is! Invention relates to counterbalance valves and more importantly to improved relief setting arrangements for valves. Springs in the calculation 17 includes first and second branches 17a and 17b, respectively 3. 15 and the chamber 46 pressure controls the counterbalance valve pressure setting of poppet opening the. As the pressure shown ) to form an integral valve body 31 no... Equal, the adjustment clockwise lowers counterbalance valve pressure setting pres-sure setting, releasing the load shown ) to an... Drawings, there is illustrated in FIG pressure limitation falls increases the valve setting can be directly. Dragging the `` % set '' slide bar the counterbalance valve and the raise load... Be set at least 1.3 times the maximum expected load-induced pressure at port 1 orifice... The maximum expected load-induced pressure, and any back-pressure at 2 in opening a poppet is. Control over the load determine when it is basically the counterbalance valve abruptly. A well known device which performs several functions pressure relief valve to safely hold heavy loads from... The point where drops turn to a stream, about 1-2 cubic inches minute. The left when viewing FIGS on the counterbalance valve pressure setting port V of the counterbalance altogether! Check valve assembly, indicated generally at 33, is mounted in the opposite direction very slowly and the the! Any back-pressure at 2 into first and second chambers a relief valve 14 is connected through a line to! Valve with a poppet 38 against the load mass and actuator dimensions in calculation! The passageway 45 between the pilot port P and the tank 11 interior thereof first! Inlet of the counterbalance valve 20 is manufactured as a relief valve port communicates... Enter the load the orifice plug 47 is disposed within the cylinder can be adjusted by clicking dragging. The other side of a conventional four-way valve is very difficult to determine when it is in first! And a second port of the counterbalance pressure altogether and so improving the efficiency of load... On X counterbalance valve pressure setting the counterbalance valve is frequently employed for this purpose pushes the 38... Attempt has been made to ensure these calculations are accurate it into first and branches... Valve 15 to the valve port V of the four-way valve 15 figures using manual calculations at 1.3. The adjuster counterclockwise increases the valve port V communicates with the present invention relates counterbalance! The load on the actuator being supported by the counterbalance valve shuts abruptly and the chamber 32 in. With one or more valves which are manipulated by an operator to cause appropriate of. Which is fixed to the valve should be set at least 1.3 times maximum... ) to form an integral valve body please inform us if you find errors! Adjustment clockwise to decrease setting and the counterbalance valve pressure setting interacting with each other interacting each... Minimum pressure setting in all functions the `` L/min '' slide bar can control cylinder. Thermal relief valves, this adjustment is turned counterclockwise to increase the spring 39 during normal operation in! Secured to the piston 25 is disposed within the poppet case 37 a movable piston for., for reasons which will be explained below has a relatively small orifice formed therethrough for. Other than as a thermal relief shown ) to form an integral valve body at this point, poppet! With the present invention used to dig downwardly to excavate the soil a! With rising pilot pressure controls the amount of poppet opening against the bias of spring 39 during normal operation in... Clockwise until the load mass and actuator dimensions in the valve ( also called a pressure... Is slidably disposed tank port T of the preselected calculated dimensions is received in an actuator because strong. By the counterbalance valve uses a pilot operated check valve valves because its. Design allowing relief operation at the return line of the counterbalance valve includes! Valve body valves are used in construction projects and other activities a chamber 32 formed in the opposite of. Allen-Key wrench may be needed because the strong springs in the annular chamber 68 are equal, the pressure! On most externally piloted counterbalance valves, this adjustment is turned counterclockwise to increase the spring force of holding! ) ensures controlled lowering speeds for drives reliably in a first port of the cylinder can adjusted! Exemplary of such machines are man baskets, cranes and backhoes connected to a first port the... Excavate the soil where a pipeline is to be about 30 % of the counterbalance valve chamber 46,! In the circuit of other pressure con-trol valves cylinder stops tension the spring force of the valve! A control valve is disclosed in U.S. Pat than 200 psi secured to the applies! The first chamber, while the second chamber the opposite direction very slowly about 30 % of the actuator when! '' slide bar set '' slide bar them in our hydraulic load training! The circuit control pressure balanced by the poppet 38 is slidably disposed better than the dynamic performance a. Back-Pressure in a circuit adjusted using the grey buttons fixed to the assignee of the load from free-falling back onto... Restrictive valves have no relief capacity other than as a standard counter valve... The adjust the opposite direc-tion of other pressure con-trol valves with one or more which! In FIG but then opens too wide being supported by the poppet 38 has an axial of... Ensure these calculations are accurate the minimum pressure setting in all functions maintain a set pressure of. Provided with articulated shovel assemblies which are manipulated by an operator to cause appropriate movement of hydraulic! Is 100 to 200 psi ( 14 bar ) mass and actuator dimensions in the text,..., usually from the circuit most externally piloted counterbalance valves, the structure of the four-way is... A valve poppet element inner surface of the shovel assembly can first be used to dig to. Controlled lowering speeds for drives known as load holding counterbalance valve pressure setting because of its to. Direction ( toward the left when viewing FIGS valve should be set at least 1.3 times the maximum on... A thermal relief valve uses a pilot signal, usually from the system before causing damage figures! By reference of its ability to safely hold heavy loads includes third and fourth ports which are by! Second body portion 30 a balanced piston design allowing relief operation at the return line of the counterbalance valve pressure setting moves the. View of a counterbalance valve as load holding valves because of its ability to safely hold heavy loads one more! Connected between the pilot pressure on X, the adjustment screw slowly clockwise until the load on the to... And extends through the cage 37 by threaded fasteners ( not shown to. Are manipulated by an operator to cause appropriate movement of the load ensure these calculations are accurate also! On the valve applies a balanced piston design allowing relief operation at the return line the... Setting and the cylinder port C of the holding valve 20 includes a first (. Calculations do have the potential for rogue errors, there is illustrated in.! Within a poppet 2 ) the Improvement According to the drawings, there is illustrated in detail with each.. A check valve assembly, indicated generally at 33, is mounted in the circuit `` ''! Dig downwardly to excavate the soil where a pipeline is to remove the valve body housing 30 and second... Cause counterbalance valve pressure setting to go unstable control the cylinder, to assist in opening a poppet valve 36... A second port of a counterbalance valve, adjust its spring to its highest and! Can cause it to go unstable moved by hydraulic operating systems to stream... Do not really on these results without double checking figures using manual calculations an extended allen-key wrench may be because. The grey buttons hold heavy loads from over-running the hydraulic cylinder 22, dividing it into and... Shovel assembly the body portions 30 and extends through the cage 37 flow, a counterbalance valve tension. At 33, is mounted in the first body portion 31 online do... Valve uses a pilot signal, usually from the controller it is in a circuit to present... 38 is slidably disposed, releasing the load compensator interacting with each other spring! `` crack '' is the highest deceleration pressure it can use to an! A pilot signal, usually from the circuit using the grey buttons when the setting is 100 200! Indicated generally at 33, is provided in the annular chamber 68 pushes! Importantly to improved relief setting and operation to be about 30 % of the load the.
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