A spool valve is used in practically every business you can think of to do a variety of duties, but what exactly is one and how does it operate?
Spool valves are used to control the flow direction of the energy source by combining or switching the routes through which the oil or air can go in hydraulics and pneumatics, respectively, where the energy source is oil and the energy source is air.
The case has many chambers that are bored through it from one side to the other; these are called “ports.”
As it moves inside the sealed box, the spool serves the purpose of either blocking or opening these ports, depending on its position.
In This Article...
What does spool valve mean?
A cylindrical valve component known as a spool moves axially within the valve bore to open and close ports. Elastomers are typically used in spool valves to shut off flow channels. Spool valves have some benefits and drawbacks compared to poppet valves, which makes them more suitable for vacuum applications, applications that need to hold pressure downstream, selector valve applications, and applications that need a constant response time.
Poppet or SpoolWhich Will Work Best for Your Application?
Think about the elements that are most important for your application when selecting the valvepoppet or spool that will best suit your needs. For instance, the closed crossover of poppet valves makes them more suitable for applications requiring precision control (no transitional state from one function to the next). Because they open instantly upon actuation and have a shorter stroke, they are also a preferable option for applications that demand quick response times. Spool valves are a better option if your application calls for predictable reaction times or uses a vacuum. The graph that follows is a nice place to start. Have more inquiries? For assistance, get in touch with Clippard or a nearby distributor.
What results in a spool valve failing?
Sliding spool/bore valves are the most common type of DCV valve. When a valve sticks, typical force applied by the operator will not cause the spool to move. This sticking action can be brought on by a number of things, such as pollution, silting, mechanical failure, or operator error. Let’s examine these typical causes.
The usual amount of force needed to move the spool increases beyond the operator’s capabilities when hard particle contamination occurs between the bore and the spool. As soon as the contamination is removed, the spool becomes stuck and cannot be moved. The bore and spool will be harmed by forcing the spool to move, leading to wear and gouges. This creates a circle of contamination that damages the valve more and more until it starts to leak excessively. The most effective technique to stop the sticking action is to disassemble the valve and remove the contaminants before it does more harm.
In contrast to hard contamination like sludge and varnish, silting typically involves soft contamination. The operator cannot create enough force to move the spool past the silt in the hydrostatic lands and bores because silting increases the sliding force required to move the spool. The easiest technique to stop a silting activity is to disassemble the valve and thoroughly clean every component.
A DCV contains a lot of tiny, fragile parts, many of which are prone to breaking. A broken spring, pin, washer, or detent device might jam or stick the valve. It will be necessary to replace the damaged components or the valve entirely.
The DCV changes position in response to an external stimulus of some kind. Electrical (solenoids), hydraulic (pistons), mechanical (levers and rods), and pneumatic operators are the most prevalent types (pistons). The first thing to determine is whether the operator is sticking the DCV or if a problem with the hydraulic element of the DCV is to blame. To allow the mechanic to manually manipulate the valve, the majority of valve operators feature a tiny mechanical component called a manual override. If the valve shifts with the manual override but not with the usual signal, there is probably a problem with the operator. When using the manual override, if the valve won’t shift, there’s probably a hydraulic or mechanical issue with the DCV. The solenoid coil burn out that can result from a failure of the hydraulic portion of the valve must be fixed when the DCV is disassembled and rebuilt.
Which two spool valve types are there?
The spool valve is most frequently employed in hydraulic systems due to its design of internal moving elements.
A spool valve is what?
Applications, Types, and Configurations
- Center Valve is closed.
- Close the center valve.
- Center valve in tandem.
- Center Float Valve.
How much does replacing an oil control valve cost?
An oil control valve repair could cost as much as $350. While the cost of labor ranges from $80 to 160, the cost of the parts is between $100 and $200.
What makes it a spool valve?
Spool valves would move backwards and forwards, allowing fluid to flow through a network of pipes in either direction. Spool valves consist of two main parts: a cylindrical barrel into which a plunger or spool glides.
How is a spool valve adjusted?
You might need to change the spool valve if the hydraulic fluid pressure is too low or excessive, which will save your business time and money. You can safely set the valves to the factory-preset pressure and pressure range. To prevent harming the valve and decreasing its effectiveness, stay within this range.
Pressure can be calculated with the aid of flow rate. Manufacturers set the spool valve pressure at a standard rate of 10 gallons per minute. To compensate for the higher pressure caused by the increased fluid flow, reduce the valve’s pressure for higher flow rates. In contrast, low flow results in low pressure; to make up for this, pressure is increased.
Leasing the valve-locking nut on the side will let you to adjust the spool valve. You may access the adjustment screw by removing the locking nut. To increase pressure, turn the screw in a clockwise direction; to decrease pressure, turn it in a counterclockwise direction. Before replacing the locking nut and reinstalling the spool valve, use a pressure gauge to be sure you’ve created the proper pressure adjustment.
If the spool valve has been correctly set and the issue persists, you might need to try checking the hydraulic system’s valves. There are often just three basic problems with these hydraulic parts. However, just because there aren’t many issues doesn’t mean troubleshooting will be simple.
The way a spool functions,
The carrier, spider, and side gears are replaced with an entire spool. The component is made up of a ring flange and a snout. The snout, which is splined to accept the axle shafts, is where the axles are fitted. The ring flange of the spool is bolted to the ring gear.
How is a spool valve tested?
Install a flow meter and a pressure gauge in the drain/tank port line to check this. Differential pressure is the basis of all hydraulic systems. The actuation pressure must first overcome any excessive back pressure in order to move the spool. Most systems only need a little amount of back/drain pressure to run efficiently.
What are the solenoid’s top 5 common issues?
Despite the fact that solenoids come in a wide variety of sorts, there are a few fundamental categories into which these issues can be divided. Plungers that are jammed in or out, attached valves that are locked in place, damaged internal coil windings, and excessive noise while operating are all common solenoid issues. While some of these difficulties are often caused by exterior components, others are the result of internal solenoid troubles. Different solenoid issues require different approaches to repair since while some solenoids can be repaired, others simply need to be replaced.
Electromechanical devices called solenoids are frequently employed to control the flow of different substances. An iron or steel armature and a helical coil make up the basic building blocks of a solenoid. The solenoid can predictably transform electric power into mechanical energy when it is applied. Solenoids are frequently used in conjunction with valves to control whether or not a signal from an electrical source has been applied. In other circumstances, solenoids can be employed to carry out additional mechanical tasks, including closing a group of contacts.
Many typical solenoid issues are related to this system because solenoids rely on inductive coils to function. A solenoid may stop functioning properly due to faulty internal windings, and coils may melt, burn, or simply short circuit. If the armature is bent or dirty, if there is too much heat or moisture present, or if the wrong voltage is given to a device, similar problems may develop.
Why is there a 2 spool valve?
- All spools have a spring-return to neutral position and are double acting. Double acting cylinders are managed by a spool.
- Tank has no access to ports A or B when in the neutral position.
- T port is intended for use with closed-center hydraulic systems and is closed to the tank when in the neutral position. This valve has no options for load sensing.
- The neutral position of the A and B Ports, which are intended for double-acting cylinders, is closed.
- Tank has access to ports A and B in the neutral position.
- All spools are double acting with a spring return to neutral, and a D spool is useful for applications other than those requiring load holding, such as horizontal cylinders and motors.
Valve Body Features:
- P = 5080 PSI, T = 3050 PSI, A & B = 5080 PSI are the maximum operating pressures.
- Female thread #12 SAE (1 11612 ORB) Inlet (Pressure) Port
- 3000 PSI Capable
- Work Ports with a #12 SAE (1 11612 ORB) female thread
- Rated Flow: 25 GPM
- Body in aluminum
- a sturdy aluminum enclosure constructed for use
- Outlet (Tank) Port: #16 SAE (1 5/16 -12 ORB) female thread
What occurs if an oil control valve is not replaced?
The VVT solenoid and OCV work together as a single unit. This device might break down. When it does, any one or more of these signs may serve as a warning sign for issues:
#1Rough Idle
The VVT system normally engages at higher RPMs or during load-bearing situations, such as while climbing a hill. However, a defective oil control valve or VVT solenoid may allow too much engine oil to enter the VVT system, which can cause rough idling, stalling, or just generally poor engine performance.
#2Poor Acceleration
The engine’s acceleration will be slower than usual. There won’t be enough energy to accelerate swiftly or climb hills. Even though you might not think this is a huge concern, there might be moments when you have to floor it to avoid an accident. There isn’t much you can accomplish without that power.
#3Poor Gas Mileage
Variable valve timing has several advantages, one of which is improved fuel efficiency. However, if the oil control valve is broken, this advantage is lost because the intake and exhaust valves could open or close at the wrong times. You will observe an increase in gasoline use over time.
#4Check Engine Light
The check engine light (CEL) will always come on. The onboard diagnostic system will set a code (OBD2). This code will let you know if the issues you’re experiencing are linked to the OCV and its associated VVT solenoid. These two DTCs, P0014 and P0017, are both connected to VVT.
The automobile may be driven for a short distance, as with all CEL “on” events, but a service specialist must quickly inspect it for repairs.