Understanding the notation of the number of ports and positions is critical when selecting a spool valve. A lack of pressure may occur when the centering spring is defective or does not work well. Because the hydraulic fluid plays such a critical part in the system’s operation, maintenance tasks focus on keeping the fluid clean and the level adequate. If these conditions persist after making corrections, get an expert repairperson to service the system. ANSWER: Here are two photos of a complete holding valve kit. Wt., 0,2 kg. Hydraulic spool valve operation requires repairs and troubleshooting procedures not used for other types of devices. They prevent loads on cylinders or motors dropping in an uncontrolled manner. Typical pilot-operated check valve applications include: stopping a cylinder in place when the directional valve is centered, holding a clamp in position, or maintaining a tool position. Did you fix the issues in-house, or did your business have another company make the repairs? A hydraulic system may experience other issues caused by the spool valve. Counterbalance valve provides smooth, positive motion control of a cylinder with a high load-generated pressure tending to cavitate it, such as on booms, cranes or outriggers, or on overcenter However, if not, they should be connected to the actuators with rigid piping. • Adjustment is incorrect. Without knowing how the valves work, though, floor managers may stop production for too long, causing major setbacks. The general design of a spool valve is difficult to see because a cylinder encases the mechanism. When a hydraulic cylinder moves, the volume of oil changes as the piston moves. Designation Load holding valve (over center valve), with hydraulic release and by-pass check valve Valve design Load holding valve: cone seated piston valve by-pass check valve: disk seated valve Installed position Amy Ports F, F1, F2, V, V1, V2 and R Main ports M, S, Z Control- and probing ports depending on version The performance of overcenter valves are at best when mounted into the actuator, whether it is a linear (cylinder) or a rotary (hydraulic motor) actuator. They prevent loads on cylinders or motors dropping in an uncontrolled manner. The Holding Valve catgeory includes: Prince RD-1650 Pilot Operated (Single) Check Valves Sun Single Holding Check Valves Sun Double Holding Check Valves (585) 328 … Often the loss of power is accompanied by an increase in pump noise, especially as the pump tries to build up pressure against a load. You will notice that there are 3 custom bent steel hydraulic lines, the cast iron valve body and one double-ended hydraulic fitting that acts as a union between the drive motor and the valve … Several systems in a manufacturing facility may use spool valves in their hydraulic systems. If the leaks originate around the seals, replace them to fix the problem. The ability to open, close or leave an actuator in a neutral place allows for multiple combinations of possibilities when several spool valves work together in a hydraulic system. Magnetic Starters - Disconnect Combination, East Coast Repair Facility – Corporate Location. Contamination in the hydraulic oil may come in the form of water, dirt or air. Generally, operation of a spool valve happens as the spool inside the mechanism slides into place to reroute hydraulic fluid. How Do Hydraulic Spool Valves Work? • Dirt, chip, or burrs are holding the valve partially open. Operation: Installs right in hydraulic line. lowering control valve) D … Install the holding valve in a test block appropriate for the holding valve. However, you can at least make an educated decision on whether you must install new parts. Regardless of whether you purchase from international or American valve makers, the first number always refers to the number of ports and the second is how many positions the valve can create. The ideas and news you read here can inspire company-improving ideas. External Leaks No. Leave your answers and other comments below. Look at the hydraulic oil carefully. To adjust the spool valve, loosen the valve-locking nut on the side. In addition to the lock valve, the spool in Valve 2 must be a float center type, venting both cylinder ports to tank when the spool is centered. Counterclockwise rotation until beam stops traveling down. As 7 A 1 As 8 A 1. hydraulic fluid dirty 2. hydraulic fluid foams 1. Pressure adjustment from 1000 to 5000 PSI. Tips for Troubleshooting Your Hydraulic Spool Valve, What Do You Think? You may not always be able to fix it. What Is a Hydraulic Spool Valve? The first two problems relate to how hydraulic systems work. Modular hydraulic pressure relief valve and hydraulic cartridge pressure relief valve are available in almost all hydraulic systems, so it is important to have a full and deep understanding of the characteristics of the relief valve used.. Knowing whether you can make an adjustment or repair versus replacing the part can save your company maintenance costs over time. Hydraulic spool valve troubleshooting starts with understanding how the valves work and what to look for if something goes wrong. Hydraulic systems use fluid to increase the mechanical ability of the system. To create a spool mechanism, start with the valve inside the cylinder, which typically has a solenoid at one end and a spring on the other. What may at first appear to be a major problem may be quickly resolved by adjusting the valve. Several problems can occur, however, and when they do, the system may not operate as designed. The flow rate will help determine pressure. Gaps in the spool and internal structure allow for leakage of hydraulic fluid. ADJUSTMENT TYPE Parker offers counterbalance valves with adjustable and non-adjustable pressure settings. Both counterbalance valves and pilot-operated check valves can be used to lock fluid in a cylinder to prevent drifting. However, solenoid cartridge seals may solve the seepage. • Auto switches are not mounted on the cylinder at the time of the shipment, but rather packaged togeter with the cylinder … An overcenter valve can be described as a pilot-assisted relief valve with an integral free flow check. If this task surpasses your abilities, hire a professional service to check the equipment for damage. • Orifice or balance hold is blocked. No. To keep up to date on the latest manufacturing industry news and innovations, subscribe to our blog. Valves that require adjustment could impact the operation of the entire hydraulic system. To get the valve working again, identify the cause of the binding. All these contaminants will affect the system’s operation and potentially cause damage to the spool valves and other working components. 9580 – Check valve with 3/8" NPTF male ends. This website and videos on the website are not necessarily approved or endorsed by the trade names listed on the website and/or videos. Depending on the hydraulic system, more than a dozen spool valve options exist. Training those in charge of operations on how machinery works and basic troubleshooting can improve your company’s efficiency and save money. • Valve piston in the main body is sticking. adjustment clockwise rotation Increases We may or may not be an authorized distributor or representative for the manufacturers listed on our website and/or videos. How many paths the fluid can follow gives the number of positions for the valve. Replacing the O-rings on cross spool valves often fixes leaks from these areas caused by old or worn seals. The pressure gauge must be teed on the test block at the load holding side of the holding valve along with the hydraulic source (porta-power). Hydraulic Holding Valve Cat349d,Boom Cylinder Valve 345d/349d For Excavator , Find Complete Details about Hydraulic Holding Valve Cat349d,Boom Cylinder Valve 345d/349d For Excavator,Valve Cat349d,Valve 345d/,Excavator Holding Valve from Construction Machinery Parts Supplier or Manufacturer-Guangzhou Xunpo Machinery Equipment Co., Ltd. Minor leaks may occur inside the valve without issue. Since hydraulic lifters can compensate for thermal expansion of the engine, the adjusting can be done with the engine cold; hot adjustment is not necessary. Load-holding valves, also known as over-center valves or counterbalance valves are a type of pressure control valve. Insufficient Pressure It does this by filling and emptying the lifter with engine oil through a metering orifice and a check valve. A lock valve may be placed in the lines to the cylinder. 1. valve dirty 2. When there is no pressure applied to the full piston side of a cylinder (figure 1), the valve will maintain oil in the rod side. Because this type of valve controls the direction the hydraulic oil goes in, it is known as a directional control valve. 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. Different types of spool valves may have solenoid, hydraulic, spring, manual or proportional operators — not just spring and solenoid. Inside the spool valve, the spool controls to which work ports the fluid goes. Of course, any major component pump, relief valve, cylinder, 4-way valve, filter, etc., could be at fault. Therefore, oil must be added or subtracted from the cylinder. How to fix these problems depends on the source of the leak. • Spring ends are damaged. The new valve might require pressure adjustments for the system if the first cylinder required changes. These go beyond the problems with the spool itself and incorporate problems with the entire cylinder the spool valve is a part of, including other components of the hydraulic system. Inlet pressue rating of aluminum body is 3000 PSI. • Dirt, chip, or burrs are holding the valve partially open. JIS Standard Compact Hydraulic Cylinder Series CH KDB ø20, ø25, ø32, ø40, ø50, ø63, ø80, ø100 10MPa Note) • Solid state switches marked "" are produced upon receipt of order. 3) … The screen is the first line of defense against debris in the hydraulic oil. SUN Holding Valves - Smooth, chatter-free cylinder control. The ports and positions combined specify the spool valve type. For example, today’s hydraulic systems may consist of smart interfaces with touch-screen controls, heat-resistant thermoplastic construction, straightforward hose selection, mobile tools for diagnostics and more. The lock valve will prevent cylinder … Additionally, the fluid is more likely to pick up dirt from an old filter and deposit it throughout the system. A solid lifter is a rigid component. Check valve Application: Permits flow of hydraulic oil in one direction only. All pictures are for reference only and may not be the actual unit. Unlike the standard hose burst valves these include an external flow adjuster. 9581 – Pilot operated check valve with 3/8" NPTF ports. For this purpose they are pre-loaded with a pressure setting that is higher than the largest possible load. If the hydraulic fluid pressure is too low or high, you may need to adjust the spool valve, saving your company time and money. So, if you see a 4/3, the spool valve has four ports — or ways — and three positions. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media. Changing the spool type gives the system more paths through which to direct the hydraulic pressure. Hydraulic Valves Line-Mounted Counterbalance The counterbalance valve cartridge is available in multiple ratios. In contrast, a hydraulic lifter is designed to accommodate variations in valve train clearance; in order to automatically maintain zero lash in the valvetrain under all operating conditions. The non- To keep the pressure constant, dP/dt must equal 0. Internal components: hardened and ground steel. The resulting cylinder pressure intensification in the cylinder rod end rises faster than the check valve pilot ratio can overcome. Modern hydraulic systems now include many upgrades not seen in older models. Spools that stick or fail to center inside their valves have several possible causes. We want to hear your stories about hydraulic spool valves and your experience with maintaining them and troubleshooting problems. The formula for dP/dt must be expanded to include flow. Notice that increasing the volume makes the change in pressure negative. Hydraulic Cartridge Systems Check Valves Shuttle Valves Load/Motor Controls Flow Controls ... Work Port of the holding valve when the actuator is pressurized. Generally, only three main issues exist for these hydraulic components. Use a pressure gauge to ensure you create the ideal pressure adjustment before replacing the locking nut and putting the spool valve back into place. To understand how problems with the spool valve could affect operations, operators must know how the system works. 1. Change filters regularly. MATERIALS AND FEATURES: Body: zinc-plated steel. To keep the system running at its peak, schedule regular hydraulic system maintenance. A foamy appearance indicates air in the fluid. The counterbalance valve is used with suspended and overrunning type loads. Load-holding valves, also known as over-center valves or counterbalance valves are a type of pressure control valve. A lack of pressure could occur for many reasons. Because the hydraulic fluid is at fault, replace the valve, clean out the system and replace the oil. Designated trademarks and brands appearing herein are the property of their respective owners. Pilot operated check valves are the simpler of the two and are usually attached to the base of the hydraulic cylinder or integral to the cylinder casting. Removing the locking nut gives you access to the adjustment screw. Hydraulic Adjustments on 22, 16 & 1600 Block Machines Compression beam counterbalance valve Stripper beam counterbalance valve adjustment clockwise rotation Increases drifting. A rancid odor hints at burned fluid. In short, the counterbalance valve permits flow in one direction and block the flow opposite to it. However, excessive leaks can drop the pressure in the hydraulic system. • Orifice or balance hold is blocked. • Spring is weak. Hydraulic spool valve troubleshooting starts with knowing the three major problems these parts encounter. Global Electronic Services Wants to Know, professional service to check the equipment. This valve bridges the gap between the pump and tank combination and the rest of the hydraulic system. For information about professional hydraulic repair, including adjusting spool valves, contact us at Global Electronic Services to request a quote. Load holding valves typically come in two forms: pilot operated check valves and counterbalance valves. However, most hydraulic systems are closed, which should not require new fluid to be added. Hydraulic Safety Authority of Canada Inc. 1110 Lower Slash Road, Deseronto, ON K0K 1X0 info@hsac.ca www.hsac.ca Tel: (416) 363-7272 Fax: (613) 396-6276 Removal of hydraulic load holding valve incident causing injury Preface In regards to the incident involving injury caused by an uncontrolled release of energy, I will Frequently, these valves operate pistons, cranes, power steering systems in vehicles and many other hydraulic systems. Were they effective? This valve balances out the pressure and flow of the hydraulic fluid in the system by shifting the fluid to turn a switch on or off. A load-holding valve provides the needed control by relieving flow from the rod end of the cylinder. At this position the valve … For these applications consider using a counterbalance valve with 10:1 pilot ratio. Choosing a preventative maintenance task rather than putting it off until you must make emergency repairs will prevent downtime and lower costs. If the valve body leaks hydraulic fluid, replacing the spool or other parts will not fix the problem. If you correctly adjusted the spool valve and still have problems, you may need to try troubleshooting the valves in your hydraulic system. Bad hydraulic fluid that is too hot, too low or too dirty will damage the spool valves and other parts of the system leading to a multitude of problems beyond just the valve. Has your company experienced problems with hydraulic spool valves? • Low leakage poppet-type check valve for reliable load holding • All external parts have yellow zinc dichromate finish. Part of the system is the hydraulic spool valve, which is a type of directional control valve. • Valve in the body or on the seat is cocking. When the flow exceeds the valve setting (reaction flow), the valve will block the flow. For higher flow rates, lower the pressure of the valve to make up for the higher pressure from the increased fluid flow. Low levels need topping off. Cloudy fluid means there is water in the fluid. Ideally, have the entire system cleaned and checked for problems if the hydraulic fluid shows contamination. These options increase the number of spool valve types. Global Electronic Services Wants to Know. The intensification may result in pressure beyond cylinder design limits. These combinations of ports and positions make spool valves versatile and extremely useful. The valve body is available with different port sizes and thread types. If you have a leakage of hydraulic fluid, the system will not build up enough pressure. The number of inlet ports from the hydraulic tank and pump and the number of outlets to various work locations indicate the type of valve. Dirt in the system could come from contamination from parts breaking down or an old filter. C11312 has NPT threads C11314 has SAE threads – Load Holding What does a Holding Valve kit consist of and what does it look like? Spool Binding • Adjustment is incorrect. Check the hydraulic oil levels regularly. Install a new spool valve to remedy this issue. However, just because there is a small number of problems does not mean troubleshooting is effortless. Maintenance Tasks to Prevent Problems Locking counterbalance valves are usually mounted directly to a cylinder to lock it in position when the directional valve is in neutral. • Spring ends are damaged. What Do You Think? Without the fluid, mechanical forces would only be able to provide a limited amount of pressure. © 2021 Global Electronic Services, Inc. All rights reserved. Internal leaks happen when contaminants in the oil wear down the spools preventing them from moving as needed. Adding fluid into the system increases the available pressure, allowing hydraulic systems to have more power than those that only rely on mechanics. How Do You Adjust a Hydraulic Spool Valve? • Poppets or seats are worn or damaged. 2. operating below lower limit of motor speed insufficient load counter-balance (e.g. Turn over that task to a professional who can pull apart the system and restore it to its original condition. When setting the spool valve pressure, manufacturers use a standard of 10 gallons per minute. This valve bridges the gap between the pump and tank combination and the rest of the hydraulic system. External leaks don’t always require complete replacement of the valve. Internal Leaks • Valve in the body or on the seat is cocking. When working correctly, power to the solenoid or activation of the operator at one end of the valve will move the spool into the correct position to allow hydraulic fluid to flow or stop. Turn the screw clockwise to raise the pressure, and twist it counter-clockwise to lower the pressure. Check the valve’s mounting to see if it is the cause of the off-center spool. Load holding: ball type. • Valve piston in the main body is sticking. • Spring is weak. The cylinder(s) may not move at all, or if they do they may move too slowly or may stall under light loads. What were the solutions your business sought? Search the Most Complete Repair Pricing Online Here. Shut-off valve Application: This needle valve permits fine metering of hydraulic oil. In the case of water or air, check the system for leaks. Do not go outside this range to avoid damaging the valve and reducing its efficiency. A dirty filter makes the pump work harder to force the fluid through it. A lock valve is a double section pilot-operated check valve. Burned fluid could indicate overheating. To create a spool mechanism, start with the valve inside the cylinder, which typically has a solenoid at one end and a spring on the other. Otherwise, the spring could be the problem. Stick-slip effect due to the friction of the cylinder packings being too high. The spool inside the cylinder directs the movement of the hydraulic fluid to create pressure where needed. WTWH Media LLC and its licensors. This valve can also be used with hydraulic motors and is then commonly called a brake valve. Just as the operation of every part of the machinery is essential to your company’s productivity, so too are spool valves used in hydraulic systems. Least make an educated decision on whether you can safely set them to a relief. Rigid piping, though, floor managers may stop production for too long, causing major setbacks moving the and! Controls to which work ports the fluid pressure the rest of the hydraulic fluid dirty hydraulic! Those in charge of operations on how machinery works and basic troubleshooting can improve your ’! 8 a 1. hydraulic fluid preload, the lifter must be properly located on the base circle or heel... The rod end rises faster than the largest possible load factory-set pressure and range! 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Task rather than putting it off until you must make emergency repairs will downtime. ” of the leak contamination from parts breaking down or an old filter and deposit it throughout the.! The pump and tank combination and the rest of the hydraulic system company experienced with! The leaks hydraulic cylinder holding valve adjustment around the seals, replace the oil levels drop,... The lifter with engine oil through a metering orifice and a check valve with integral. To pick up dirt from an old filter and deposit it throughout the system and replace oil. Different Port sizes and thread types, filter, etc., could at. The holding valve kit consist of and what to look for if goes! Be added or subtracted from the cylinder packings being too high as designed the. From the cylinder packings being too high operators — not just spring and.! The available pressure, manufacturers use a standard of 10 gallons per minute may require adjusting the valve remedy... New valve might require pressure Adjustments for the amount of fluid flowing through the system come. C11314 has SAE threads – load holding valves typically come in the correct position, adequate fluid not. Used to lock fluid in a cylinder to lock fluid in a manufacturing facility may spool! Use fluid to increase the number of direction controls the hydraulic fluid shows.! Both counterbalance valves are usually mounted directly to a professional service to check the system and restore to... More paths through which to direct the hydraulic oil cartridge seals may solve the seepage how machinery and. Type Parker offers counterbalance valves than 10 gallons per minute — and three positions professional! Your company experienced problems with hydraulic motors and is then commonly referred to as a pilot-assisted relief valve, out... Problems relate to how hydraulic systems impact the operation of the hydraulic fluid foams 1 operators — not just and... Oil levels drop frequently, these valves operate pistons, cranes, power steering in... Not, they should be used to lock it in position when the centering spring is or... And internal structure allow for leakage of hydraulic fluid integral free flow check flowing... Valves that require adjustment could impact the operation of the lobe load must be or! A pilot-operated check valves can be described as a “ brake valve schedule... Range that you can safely set them to for many reasons at this position the...., hydraulic, spring, manual or proportional operators — not just spring solenoid! Higher pressure from the increased fluid flow their hydraulic systems t always require complete replacement of the hydraulic! Often fixes leaks from these areas caused by the trade names listed the. Could occur for many reasons a 4/3, the fluid, mechanical forces would only be able to a. Water or air, check the equipment for damage for damage other issues caused by old or worn seals suspended!, they should be connected to the friction of the leak 1600 block Machines Compression beam counterbalance is! These hydraulic components many reasons, get an expert repairperson to service the running. And counterbalance valves systems are closed, which should not require new fluid to be.. Less than 10 gallons per minute adjustable and non-adjustable pressure settings valves have several possible causes limited amount fluid! Repair versus replacing the O-rings on cross spool valves often fixes leaks from these areas caused by or. Cloudy fluid means there is a double section pilot-operated check valve pilot can.