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CV08
HYDRAFORCE
This product is a threaded cartridge-type one-way valve specifically designed for the hydraulic systems of forklifts and other mobile construction machinery. It adopts an advanced screw-in installation design and is directly integrated into the hydraulic valve block. It is an ideal core component for constructing compact, efficient and reliable hydraulic circuits. In forklift applications, its main function is to allow the hydraulic oil to flow freely in one direction and reliably block reverse flow, thereby ensuring that the lifting cylinder maintains its position under load and preventing goods from falling rapidly due to accidental rupture of the pipeline. It is a key component for ensuring the safety and stability of forklift operations.
This valve is based on the classic lift type (Poppet Type) or ball valve structure. In the forward flow direction (typically from port A to port B), the oil pressure overcomes the spring force of the light load, pushing the valve core open and enabling the low-loss flow of the oil. When the oil flow attempts to reverse (from port B to port A), the system pressure and the spring force work together to tightly press the valve core against the valve seat, forming a hard seal between metal and metal or metal and sealant, thus achieving reliable locking with zero leakage or extremely low leakage. Some models also come with a pilot control port (port X). When reverse unloading is required or if there is a need for controlled descent of the oil cylinder, the valve core can be actively opened by applying pilot pressure, allowing for controlled reverse flow of the oil.
Compact structure, high integration: Adopting a threaded insertion design, it does not require additional connection pipelines or installation brackets, significantly saving space. It is particularly suitable for working conditions where the internal layout of equipment is tight, such as for forklifts.
Installation and maintenance are convenient: Simply insert it into the pre-machined standard holes of the valve block using standard tools. The installation and replacement process is fast, significantly reducing maintenance time and costs.
Outstanding sealing performance and reliability: The precise valve core and valve sleeve are well-matched, along with high-performance sealing components, ensuring excellent sealing performance even under high pressure. The internal leakage is extremely low (less than 1 drop per minute), effectively preventing load drop.
Excellent anti-pollution and anti-vibration capabilities: The robust structural design and wide tolerance for oil cleanliness (typically requiring NAS 8 grade or ISO 17/14) enable it to ensure stable operation of forklifts in complex and highly vibrating working conditions.
Wide range of pressure and flow: The working pressure covers the medium and high pressure range (commonly up to 315 Bar, and up to 700 Bar for special models), and the flow range ranges from several liters per minute to hundreds of liters, capable of meeting the various needs from small electric forklifts to large internal combustion forklifts.
Multiple opening pressures available: A variety of spring stiffness options are provided, with the opening pressure range typically ranging from 0.2 bar to 7.0 bar. Users can choose based on the system back pressure and response sensitivity requirements.
Pressure rating: | 240 bar (3500 psi) | Maximum internal leakage: | 5 drops/min |
Storage temperature: | -40 to 70 °C (-40 to 160 °F) | Ambient temperature | -40 to 70 °C (-40 to 160 °F) |
Ambient temperature: | -40 to 90 °C (-40 to 194 °F) | Fluid viscosity range: | 7.4 to 420 cSt |
Unit weight: | 0.16 kg (0.37 lb) | Internal wetted surface area | 134 cm² (20.7 in²) |
Cavity: | VC12-2 | Seal kit: | SK12-2X-B |
In a forklift, this valve is mainly applied in the following critical circuits and is the core for ensuring safety and performance:
1. Load retention in the lifting circuit: Installed in the descending oil circuit of the lifting cylinder, it functions as a hydraulic directional control valve. After the forks are raised, this valve can reliably lock the oil circuit in the lower chamber of the cylinder, preventing the slow descent of the goods due to internal leakage of the reversing valve and achieving precise positioning for a long time.
2. Safety locking in the tilting circuit: Integrated into the tilting valve plate of the multi-way valve, it forms a tilting self-locking valve. Even if the tilting control lever is operated mistakenly, this valve can cut off the oil return circuit of the cylinder, preventing the boom from accidentally tilting forward and causing a cargo overturning accident.
3. Safety protection against pipeline burst: Installed as a shut-off valve at the bottom of the lifting cylinder. When the soft pipe or connector of the cylinder suddenly bursts, the sudden increase in oil flow speed generates a pressure difference that causes the valve core to close rapidly, cutting off the return oil and preventing the load from falling out of control, providing crucial passive safety protection.
4. Internal function integration of the multi-way valve: As a basic component, it is integrated into the multi-way reversing valve of the forklift to prevent the flow of oil from intermixing between the various working connections, ensuring the independence of the actions.
When choosing the appropriate one-way valve for your forklift system, consider the following factors:
1. Function requirements: Do you need a simple one-way stop valve or one with a reversible opening function controlled by a pilot?
2. System pressure and flow: Select the model with the corresponding pressure rating and diameter based on the maximum working pressure of the system and the maximum flow through the valve.
3. Installation interface: Confirm the pre-machined hole types on the valve block (such as SUN, HydraForce, ISO standards, etc.), and ensure that the threads and sealing forms match.
4. Opening pressure: Select the appropriate opening pressure based on the system back pressure and the allowable pressure loss. An excessively high opening pressure will increase unnecessary energy consumption.
5. Compatibility of medium and seal: Determine the type of hydraulic oil used in the system and select the valve with the corresponding sealing material.
• Installation: Ensure that the valve block mounting holes are clean and free of burrs. Use the recommended torque with a dedicated wrench to tighten the screws, and avoid over-tightening which could damage the threads or seals.
• System cleanliness: Before installation, it is essential to ensure that the system piping and oil are clean. It is recommended to install a high-precision filter (preferably with a 10μm or higher precision) at the oil inlet.
• Daily inspection: Regularly check for any external leakage in the system and listen for any abnormal noises. If the load reduction rate increases abnormally, it may indicate severe internal leakage in the valve. In such cases, it is necessary to inspect and replace the valve.
Why choose our dedicated one-way valve for forklifts?
We have been deeply involved in the field of hydraulic components and have a thorough understanding of the demanding conditions of forklift operations. Our products are made of high-quality materials, undergo precise processing, and are 100% tested before leaving the factory, ensuring that each valve is of outstanding reliability and long service life. We offer comprehensive technical support and flexible customization services to meet the specific needs of different OEM manufacturers. Choosing us means selecting a durable hydraulic safety guardian for your forklift.
Operating Pressure: 207 bar (3000 psi)
Proof Pressure: 255 bar (3700 psi)
Flow: See Performance Chart
Internal Leakage: 0.15 cc/minute (3 drops/minute) max. at 207 bar (3000 psi)
Temperature: -40 to 120C with standard Buna seals
Coil Duty Rating: Continuous from 85% to 115% of nominal voltage
Response Time: First indication of change of state with 100% voltage supplied
at 80% of nominal flow rating: Energized: 40 msec. De-energized: 46 msec.
Initial Coil Current Draw at 20C: Standard Coil: 1.2 amps at 12 VDC;
E-Coil: 1.4 amps at 12 VDC; 0.7 amps at 24 VDC
Minimum Pull-in Voltage: 85% of nominal at 207 bar (3000 psi)
Filtration: See page 9.010.1
Fluids: Mineral-based or synthetics with lubricating properties at viscosities of
7.4 to 420 cSt (50 to 2000 sus); See Temperature and Oil Viscosity, page 9.060.1
Installation: No restrictions; See page 9.020.1
Cavity: VC08-2; See page 9.108.1
Cavity Tool: CT08-2XX; See page 8.600.1
Seal Kit: SK08-2X-T; See page 8.650.1
Coil Nut: Part No. 7004400;
For E-coils manufactured prior to 1-1-04, see page 3.400.1 for coil nut info.
A1: "Threaded cartridge" refers to a specific installation method. This type of valve has a shape like a threaded sleeve, which is directly inserted into the pre-drilled standard holes on the hydraulic valve block (integrated block), without the need for additional pipe connectors or mounting plates. Its core advantages are:
High integration and compactness: Significantly saves space and weight, especially suitable for mobile equipment with limited space such as forklifts.
Leak-free connection: It is directly sealed within the valve block through threads and O-rings, reducing external connection points and lowering the risk of leakage caused by pipeline vibration.
Easy to maintain and replace: In case of failure, simply unscrew and replace the valve block, without the need to dismantle the entire pipeline system. The maintenance efficiency is high.
In contrast, the tubular valve requires threaded connections for the pipelines, while the plate valve needs to be bolted to the installation surface. Both of them occupy more space and have more connection points.
A2: It serves as a crucial "safety lock" and "one-way pass" in forklifts, and is mainly applied in:
Lifting cylinder circuit (most critical): It is used as a hydraulic control one-way valve or load hold valve. It is installed in the descending oil circuit of the cylinder. When the fork is raised, it can reliably lock the oil in the lower chamber of the cylinder, preventing the goods from slowly sliding down due to internal leakage of multi-way valves or temperature changes (the "soft-lifting" phenomenon), ensuring that the load remains stable in the air for a long time.
Inclined cylinder circuit: Forms the inclined self-locking valve. It prevents the boom from unexpectedly tilting forward or backward due to the weight of the cargo or uneven ground when the engine is turned off or the system loses pressure, ensuring the safety of the equipment and personnel.
Pipeline explosion-proof and rupture safety protection: As a safety shut-off valve. When the flexible hose connecting the oil cylinder suddenly ruptures, the pressure difference caused by the rapid outflow of the oil will cause the valve core to close instantly, preventing the load from falling uncontrollably and providing passive safety protection.
Prevent oil backflow: Inside the multi-way valve, it is used to prevent pressure interference among different working circuits (such as lifting, inclination, and equipment), ensuring independent and precise operation.
A3: Correct selection is the foundation for ensuring performance and safety. Please make sure to confirm the following points:
1. Function type: Is it a basic one-way valve (allowing flow in only one direction), or does it need a pilot control port for a hydraulic directional valve (able to open in the reverse direction through an external pressure signal to achieve controlled descent of the hydraulic cylinder)?
2. Pressure rating: Must be higher than the maximum working pressure of the system and leave a safety margin. The pressure of the forklift system is usually within the range of 16-25 MPa, so a valve with a rated pressure of 31.5 MPa or higher should be selected.
3. Flow capacity: Choose the model with the corresponding diameter based on the maximum flow through the valve (usually corresponding to the flow during the rapid descent of the hydraulic cylinder) to ensure the pressure loss is within an acceptable range.
4. Opening pressure: Refers to the minimum pressure difference required to open the valve. There are various specifications such as 0.2, 0.5, 1.0, 3.5 bar. Choosing an excessively high opening pressure will increase unnecessary energy loss and heat generation; choosing an excessively low one may not be able to fully close the valve when the system back pressure is high.
5. Installation interface: Must match exactly with the hole type machined on the valve block. This is the key to physical compatibility. Common standards include SUN, HydraForce, ISO 7789, etc. Check the model on the drawing (such as C08-2, C10-2).
6. Compatibility of oil and seal: Confirm the type of hydraulic oil used by the forklift (mineral oil, water ethylene glycol HFC, synthetic ester, etc.), and select the sealing material (standard NBR nitrile rubber is suitable for mineral oil; if using HFC, FKM fluororubber sealing is required).
A4: Installation is the first step to ensure performance. Please strictly follow these guidelines:
Cleanliness: Before installation, it is essential to ensure that the valve block cavity, threads, and the valve itself are absolutely clean, free of any metal shavings, dust, or fibers. It is recommended to rinse with clean hydraulic oil.
Lubrication: Apply clean hydraulic oil to the O-ring and threads of the valve to facilitate installation and prevent the sealing ring from being sheared and damaged.
Alignment and Insertion: Gently insert the valve into the hole using your hands, ensuring that the threads are properly aligned to avoid "scratching". If the insertion is particularly difficult, withdraw it immediately for inspection.
Tightening Torque: A torque wrench must be used to tighten the component to the exact torque value provided in the product manual or sample. Do not over-tighten! Over-tightening can cause the valve sleeve to deform, the seal to fail, the threads to be damaged, and even the valve block hole to crack. Typical torque values (for reference only, refer to the sample for the exact value): For the C10-2 interface, the torque is approximately 80-100 N·m.
Installation tools: Use a dedicated wrench that matches the hexagonal or internal hexagonal end of the valve. Avoid using tools that are prone to slipping, such as adjustable wrenches, to prevent damage to the valve body.
A5: This is the most common fault related to the one-way valve, usually indicating internal leakage. The troubleshooting steps are as follows:
1. Initial judgment: Raise the forks to the highest position, turn off the engine, and observe the descent speed. If the descent is significant (exceeding the manufacturer's standard, such as a few millimeters of descent in 24 hours is allowed, but several centimeters of descent within minutes is abnormal), it may involve this valve.
2. External inspection: First, check for obvious leaks in the oil cylinder piston rod seal, pipe joints, etc. on the outside.
3. Temperature test: After running for a period of time, touch the surface of the valve suspected of internal leakage. If the temperature of a certain one-way valve is significantly higher than the other valve blocks in the area, it may be due to internal leakage causing throttling and heating.
4. Pressure test: In the locked state of the oil cylinder, measure the pressure in the rod chamber and the non-rod chamber. If the pressure in the non-rod chamber (the bearing chamber) cannot be maintained or slowly drops, and there is no oil leakage externally, it can be basically determined that the pressure-controlled one-way valve locking this chamber is leaking.
5. Valve core jamming: The valve core is stuck by contaminants in the oil (such as metal particles, sealing component fragments), unable to fully return and close, also causing internal leakage.
Solution: Usually, a new one-way valve is replaced. Before replacement, it is necessary to thoroughly clean or replace the system filter and find the source of contamination. Otherwise, the new valve will soon be damaged again.
A6: The one-way valve itself is maintenance-free and has no easily replaceable parts that need to be replaced regularly. Its service life is entirely dependent on the cleanliness of the system oil and the working conditions.
Under ideal conditions where the oil cleanliness meets the standards (typically requiring NAS 1638 8-9 grade or better) and there are no abnormal pressure surges, the service life can reach several thousand or even tens of thousands of working hours, which is in line with the major overhaul cycle of the forklift.
The biggest "killer" is pollution. Solid particles will wear down the sealing bands of the valve core and valve seat, resulting in an increase in internal leakage. Therefore, the most effective "maintenance" is to keep the hydraulic system exceptionally clean, regularly test the oil quality, and promptly replace the filter elements.
If the system operates under extremely high pressure or frequent shocks for a long time, the springs may become worn out, which will affect the opening pressure characteristics.
A7: The design of the threaded cartridge valve is intended for easy replacement and maintenance. Once it is determined that a certain one-way valve is faulty, theoretically, only the valve core assembly can be replaced. This is much cheaper and faster than replacing the entire valve block or multi-way valve assembly.
1. Purchase a replacement valve of the exact same model and specification.
2. In a clean environment, release the system pressure, remove the old valve.
3. Carefully check if there are any scratches or contaminants inside the valve block installation holes, and thoroughly clean them.
4. Install the new valve with the correct torque.
A8: The main difference between the two lies in whether they can "be controlled to open in the reverse direction".
Ordinary check valve: It can only achieve one-way cutoff, and the reverse direction is completely blocked. It is commonly used on forklifts for pure cutoff protection, such as preventing backflow in certain pipelines.
Pilot-operated check valve (hydraulic check valve): Besides the basic functions of free flow in the forward direction and cutoff in the reverse direction, it also has a pilot control port (port X). When it is necessary for the hydraulic cylinder to descend, the system introduces a controlled pressure oil through this X port, acting on the back of the valve core, helping to overcome the spring force and load pressure, thereby actively opening the valve core and allowing the oil to flow back to the oil tank in the reverse direction, achieving a smooth and controllable descent of the hydraulic cylinder. This is the standard configuration for the lift return circuit of the forklift to achieve the "descending" action.
A9:
• Excessive opening pressure: This will result in unnecessary increase of system back pressure, leading to increased energy loss (converted into heat), reduction of system efficiency, and may cause "jumps" or shocks in the initial stage of cylinder operation.
• Incompatible sealing materials: If the system uses water ethylene glycol (HFC) but mistakenly installs valves with nitrile rubber (NBR) seals, the NBR sealing rings will absorb water, expand, soften, and eventually dissolve, causing severe leakage of the valve and contamination of the entire hydraulic system. All incompatible seals must be thoroughly cleaned and replaced, resulting in significant losses.
