How Does a Swivel Joint Work?

Swivel Joints come in various shapes and sizes based upon the application and the environment where it goes through. While style consideration needs to be provided to outside elements, all the swivel joints have 2 primary components: a shaft as well as real estate.

The idea behind a swivel allows the shaft to rotate while the real estate remains fixed-ready. The shaft has actually pierced holes of varying size and also depth beginning with its leading surface area. Variable opening midsts, as well as markings, define the circulation path of fluid within the swivel. Via inner design, the fluid is performed the shaft right into and also out of the swivel joint.

 

 

The real estate system includes machined flow as well as grooves to assist in liquid transfer within the swivel and also protect against cross leakages. Phoned number markings are found on the real estate outer diameter surface area and also the same can be discovered on the leading surface area of the shaft.

These numbers specify where an individual would anticipate the fluid to move in/out in between shafts as well as real estate via the machined inner passages. A collection of very carefully selected inner elements are fitted between the shaft as well as real estate at specified locations. These include seals, breaks rings, O rings, wearings, tiny bearings in specific applications.

The choice of interior parts is of vital importance while designing a swivel joint as severe interest needs to be given to the tolerances as well as the inner layout of the real estate grooves. Failing to comply with the advised layout and also machining requirements leads to leaking elements.

The flow of power, as well as signals, are sometimes required for particular applications and industries. Slide rings can be incorporated with the swivel joint via passing electrical cable televisions within the hollow inner size of the shaft.

 

Exactly how to Select a Swivel Joint?

 

In contrast to various other rotary parts in the exact same industries, a swivel joint mostly endures interior loads while functional. This is a direct outcome of pressurized fluid flowing within its interior components. To pick an appropriate swivel joint, multiple influencing factors should be thought about.

The most influencing element on a swivel joint is the inner securing option between the shaft and also housing. Really precise tolerances have to be preserved during the machining phase to create the required grooves for seals as well as inner elements to be fit.

Seals, o-rings, use rings, and bearings are inserted within these internal grooves and have to be able to endure the pressures caused by the fluid Swivel joints are rated by the manufacturer regarding their recommended operating pressures, temperatures, and speeds.

These values are directly associated with the interior elements requirements, geometric machining tolerances, and type of liquid used the substantial layout as well as area factors to consider the need to be given for a swivel joint and its ports.

Based on application needs, a swivel joint might have up to 9 different ports to provide fluid with various flows. A greater variety of paths result in substantial dimension as well as product boost.

Swivel joints can be customized in dimension as well as port dimensions with respect to application requirements. Space constraints, lots requirements, task cycle, as well as environmental surroundings are all variables that are taken into consideration while choosing an appropriate part

 

We are a swivel joints supplier, please contact us if you need them.

The History of the Rotary Joint

Throughout the 19th and early part of the 20th century, the accepted method of supplying water or steam to a rotating cylinder was through the use of stuffing boxes or packing glands, which proved inefficient. The more these sealing materials wore, the more they leaked.

 

In August of 1933, R.O. Monroe and L.D. Goff, in conjunction with a local mill, designed and built the first rotary joint. It was a device that eliminated the problems associated with stuffing boxes and packing glands and allowed the water or steam to be introduced in a much more economical method. A spring-loaded mechanical seal was used to prevent the fluid or gas medium from dispersing. The secret to the rotary joint’s mechanical success was in the seal. It allowed parts of the rotary joint to rotate with the machine, while providing a leak proof seal for the fluid or gas flowing into the cylinder.

 

 

During the late 1930s and into the 1940s, rotary joints became the preferred method to admit fluid or gas into a rotating cylinder. Still, there were some problems associated with installation of the rotary joints. After World War II, several innovations were applied to rotary joint design. One of these was the use of flexible metal hose, which allowed the rotary joints some flexibility in movement as the seal wore. By 1946, several updates had been incorporated into the original design, and sizes were added to better accommodate the needs of the various industries requiring rotary joints.

 

By 1954, a complete redesign of the rotary joint was underway, mainly to reduce the physical size of the unit and to better accommodate the needs of specific applications. By 1957, many industries were also concerned about increasing the efficiency of heating and cooling within rotating cylinders. Kadant Johnson began a program of researching the effects of various types of syphoning devices (both rotary and stationary), and the effects of syphon clearances on the overall heat transfer from inside the rolls to the shell.

 

In 1959, a 60" x 250" (1.5 m x 6.35 m) paper dryer was converted for testing by Kadant Johnson, and actual testing of both rotary joints and various syphoning devices began in Pensacola, Florida, USA. In 1962, a research facility was set up in Three Rivers, Michigan, USA; and in 1963, the first pictures of the inside of an operating dryer were produced on 16 mm film.

 

People involved in designing and operating machines that required rotating cylinders learned a great deal about steam condensing rates and the actions within a dryer from these first films. Rotary joint technology and syphoning technology was shared with industry.

 

 

Through the late 1950s and into the early 1960s, this team of researchers continued to develop new designs and gather knowledge to address the needs of general industry. The need for higher operating temperatures and speeds required that the designs of rotary joints change again. Details such as quick disconnect nipples, pressure compensators, larger sizes, and longer service life were developed.

 

Into the late 1960s and early 1970s, various new seal materials, such as plastic, Teflon™, and ceramic were also tested.

 

While the early years were focused on sealing steam and water joints, today there are thousands of configurations of standard and custom rotary joints: self-supported or externally-supported; single- and dual-flow; applications using water, air, coolant, oil, molten salt, and gas; temperatures from very low to more than 1,000° F (538° C); and speeds from 1 to 50,000 RPM.

 

We are a GHP/GHPA rotary joint supplier. Please feel free to contact us if you need them!

Hydraulic Valve Application And Maintenance

All the details of the design should be fully considered whether it can meet the needs of the device or equipment use. Before we design the hydraulic valve, we must first consider whether the hydraulic valve can meet the requirements of the entire hydraulic valve group, whether it can achieve each hydraulic machinery of each functional requirements, and finally to determine whether the design has been carried out in accordance with the principles of the entire hydraulic system. Although the hydraulic valve group is a combination of a certain number of hydraulic valves, it still has a lot of internal components, the number of these components can neither be particularly large nor reduced. If the number of these components is too much will increase the burden of the hydraulic valve group, that is, the design is not reasonable, once the number of components is small, the oil circuit integration will lose part of the role, not achieve the expected effect, and will waste materials.

 

1. The design principle of hydraulic valve

The design of the hydraulic valve is mainly for the design of the hydraulic valve group, and the hydraulic valve group must be considered before the design of the oil circuit, to determine in advance which parts of the oil circuit can be integrated, into the design of the oil circuit must pursue simple, to eliminate unnecessary steps. After determining the oil circuit, the main thing is the slant hole as well as the process hole, these things in the oil circuit should be reduced, so that as long as enough can be used, unnecessary too much, in the design of the slant hole and process hole should pay attention to the aperture and flow with the direction and location must be appropriate, to consider the overall situation, to ensure that the requirements are met. If there is some inappropriate direction or location, the need to adjust the components must ensure that it can be simple and convenient operation and maintenance.

 

The design of the hydraulic valve is first discussed in terms of the design dimensions of the hydraulic valve. The length, width, and height of the hydraulic valve set are generally determined with reference to the size of the components that make up the hydraulic valve set, for example, the height of the hydraulic valve set, without affecting the actual role of the premise, as far as possible to keep in line with the height of the components. The length of the hydraulic valve group, without affecting the layout and structure, is determined by the hole diameter of the screw hole or the size of the length.

 

The width of the hydraulic manifold is determined by roughly the same factors as the length. Next, we introduce labeling dimensions, this step is mainly applied in the design of the drawing, to label the ports of some components, apertures, the size of each group, size, etc. Finally, the design of the channel, the most important thing in this design is the layout, a comprehensive overall arrangement of the system, the classification of the oil circuit, first of all, must make the main oil circuit, and then, for the small oil circuit or other oil circuit and then gradually guide. These hydraulic valve channels, in the design of the time, must ensure that the length is appropriate, the corner is relatively small, and the hole of the oil channel is appropriate, so as to effectively control the weight, size, and volume of the hydraulic valve group, in order to make reasonable use of.

 

2. The application of hydraulic valve set

In the present situation, according to different situations and different uses of hydraulic valves, hydraulic valves can be divided into many types, this article focuses on one of them, this hydraulic valve set includes four parts, it is composed of the cartridge, control cover, pilot control valve and integrated block of two-way cartridge valve.

The following describes the main contents and functional uses of these four parts. The structure of the cartridge can be considered as a slide valve or cone valve, the role of this part of the component is very important to control the flow direction, flow rate, and pressure of the oil in the channel or elsewhere. The control cover can effectively control the cartridge valve real-time work, mainly because it is composed of a number of pilot control components, these components can regulate or control the work of the cartridge valve, this control cover is basically even a bridge, connecting the control valve and components, and, the pilot control valve should also be selected to install on it.

 

 

Two-way cartridge valve in the current situation in our country is more common, from the economic point of view, because its components and the necessary piping connection are relatively small, it is easy to integrate, so it is very convenient and suitable for large-scale go mass production, which can largely reduce production costs. From the point of view of use, its structure determines that it will be small in size so it is very convenient, and its high speed of control and switching determines that it is very efficient and reliable in use. In addition, it can be controlled with high power, which has the advantage that the loss of pressure will be reduced and the loss of heat will also be reduced. Finally, the two-way cartridge valve is not affected by commutation. The main role of the two-way cartridge valve is to connect the route of the fluid or control it to disconnect.

 

3. Maintenance of hydraulic valve

With the growth over time, the hydraulic valve will inevitably have some failure, which involves the maintenance of the hydraulic valve. In actual production, the maintenance of the hydraulic valve is mainly timely cleaning, some parts of the combination of optional, as well as the size of the repair. Hydraulic valve channels have oil, it is easy to occur the precipitation of oil, the precipitation will make the hydraulic valve some unnecessary failure, so we must promptly clean up, the hydraulic valve disassembly and then cleaning, so as to timely make the function of the hydraulic valve to restore.

 

Cleaning time to pay attention to safety, a lot of precipitation is not easy to clean and needs some cleaning fluid, these cleaning fluids are generally corrosive or toxic, and even some are flammable, so must be careful and cautious. After cleaning the finished parts must be well stored, so that it does not appear to be corroded again. After the cleaning is completed and then installed, the hydraulic valve can continue to operate after testing. If some parts of the hydraulic valve are broken and serious, in this case generally choose to reassemble the optional. Hydraulic valves if there is special experienced personnel maintenance, will greatly increase their life, and their reliability and performance will be maintained at the original level, even so, we should be vigilant in the daily production, to prevent accidents.

 

Changsong Industrial Equipment Shandong Ltd. offer various valves and system solutions required in hydraulic systems. If you are interested in our products, please contact us now!

Hydraulic Valve Repair Method

In the actual use of hydraulic equipment, due to various factors, the hydraulic valve may have some failures, thus adversely affecting the normal use of hydraulic equipment, and therefore through a scientific and reasonable method of hydraulic valve failure repair, and better solution is to ensure that the hydraulic equipment can be used normally important means. A hydraulic equipment management and maintenance personnel should have a detailed understanding of the hydraulic valve repair methods and will be proficient in order to effectively deal with hydraulic valve failure, to ensure the good operation of hydraulic equipment.

 

1. Cleaning the hydraulic valve

 

 

In the hydraulic valve repair process, the hydraulic valve disassembly and cleaning is the first process. In the actual use of hydraulic equipment, hydraulic oil pollution will lead to oil deposits or the presence of some granular impurities in the hydraulic oil, these will lead to hydraulic valve failure, usually after disassembly and cleaning will be able to remove these faults, so that the hydraulic valve can restore its function. Hydraulic valve disassembly and cleaning mainly include the following five aspects.

(1) Disassembly. Hydraulic valve, although most of its parts are connected by bolts, the hydraulic valve is designed for non-disassembly, if the lack of special equipment or lack of expertise and forced disassembly, which may lead to the result is damage to the hydraulic valve. Therefore, before disassembly maintenance personnel should master the hydraulic valve structure, and should master the connection between the various parts, in the process of disassembly should be recorded between the different parts of the location of the relationship.

(2) Inspection and cleaning. Check the valve body and spool and other parts, and observe the deposition of dirt, on the basis of the work surface does not cause damage, the use of brushes, cotton yarn, and a non-metallic scraper will be concentrated dirt removal.

(3) Rough washing. The valve spool and valve body in the cleaning box tray placed, and its heating soak, in the bottom of the cleaning tank through the compressed air, the use of bubbles generated by the stirring effect, the residual dirt will be cleaned off, in the conditions allow the feasibility of ultrasonic cleaning.

(4) Fine. First to the cleaning solution for high-pressure positioning cleaning, and then hot air drying. In the enterprise conditions, you can choose the existing freshener, on some special occasions can also be used for organic cleaning agents, such as gasoline and diesel fuel.

(5) Assembly. According to the hydraulic valve schematic or in the disassembly of the recorded parts assembly relationship for assembly, the assembly process should pay attention to careful operation to prevent damage to the parts. Some of the original sealing material, in the actual disassembly process, is easily damaged, so the assembly should be replaced.

 

2. Optional combination of parts repair

 

 

In the process of manufacturing hydraulic valves, in order to make the assembly accuracy can be effectively improved most of them choose the optional method, that is to say, a batch of processed parts, such as spool and valve body, should be based on the actual size of the most reasonable clearance must be selected, and then assembled, so that the spool can ensure a good sliding performance and good sealing performance. In other words, for the same type of hydraulic valve, its body and spool in the fit size may have certain differences exist, the actual use of the process, when the enterprise has a large number of failed hydraulic valves, can be disassembled and cleaned all the hydraulic valve, each part to check the measurement, according to the results obtained from the detection of parts, and then use certain methods to re-combine matching.

After inspection, if the valve body and spool are found to be worn, but the working surface is not seriously scratched or not seriously worn in the local, then you can choose the appropriate clearance body and spool reassembly; if the clearance between the valve body and valve and the clearance specified in the product drawings has increased, and the degree of increase in the range of 20% to 25%, then you should take certain methods Make the spool size increase, and then research and repair. For the conical valve class between the valve seat and the spool, if the conical seat valve in the contact surface sealing is not good, because the conical valve can be in the spring action to automatically compensate for the gap, so, as long as the grinding can be. If the valve body and valve wear lack uniformity or on the work surface there are scratches, the use of the above methods can not make the hydraulic valve function to get a better recovery, then the body and spool should be selected to meet the machining allowance requirements in the amount of interference, for the valve body hole, should be appropriate reaming, for the spool should be appropriate grinding so that the shape accuracy and assembly clearance can be reasonable.

 

3. Size recovery repair and maintenance

 

For repair and maintenance process, it includes many types, in hydraulic valve repair is more applicable and widely used is the brush plating repair method, the method is also known as electroplating repair. For the electric coating repair method, its repair reasonable thickness within 0.12mm, can with uniform wear hydraulic valve repair requirements basically meet, after repair still need further processing. In electroplating repair, the more common process is chemical compound electroplating, the process is based on the development of a mature electroplating process, the advantage is that the operation method is convenient, equipment is relatively simple, and relatively low cost, while relatively easy to control its reaction. In the hydraulic valve repair process, the valve hole or spool surface using the process can be precipitated out of the composition of more composite plating, the plating and plating, and the parent metal can be firmly bonded, and its mechanical strength is relatively high, the thermal conductivity is also relatively good, while its coefficient of thermal expansion is relatively low, in addition, the coefficient of friction is relatively low, and its self-healing ability is also relatively strong, so the use of this method in the hydraulic valve repair can get more ideal results.

 

Changsong Industrial Equipment Shandong Ltd. offer various valves and system solutions required in hydraulic systems. If you are interested in our products, please contact us now!

How To Maintain The Uncoiler

Uncoiler, also known as decoiler, material rack, loading rack, unwinder machine, etc., is an indispensable unwinding device for metal coil to be stamped processing. Like the feeder, it is also a product that must be used on the factory workshop. It is suitable for the continuous stamping processing industry of various auto parts, hardware and electronic parts. We know a lot about several decoilers, and different uncoiler machines have different characteristics.

The decoiler/uncoiler plays a vital role in the cutting production line, pressing production line and various metal production lines. In order to allow it to be used for a longer period of time, we need to pay more attention to daily maintenance. Here are some useful tips.

1. Grease the decoiler/uncoiler mandrel regularly.

2. It is best to expand the coil within the acceptable parameters.

3. Check whether the core rod of the decoiler/uncoiler is stuck or abnormal before starting up.

4. Operate the uncoiler correctly according to the instructions and safety regulations.

5. When abnormal noise is heard, stop the uncoiler immediately.

6. In the metal production line, every operator in charge of different machines must cooperate closely.

 

Advantages of decoiler:

 

The decoiler is suitable for conveying various coil materials. Thin thin metal and non-metal materials can be equipped with motor power and feeding device. The brake device is adjustable and the main shaft is reinforced, which makes the rolling of the material roll more stable and increases its carrying capacity. It can automatically produce indispensable parts with the punching machine, saving manpower, material resources, and reducing costs. The effect is very good.

Uncoiler machine can save feeding time and improve production efficiency. It can be used with the calibration machine. It can be equipped with a motor and electrical control instead of a power frame.

 

 

Safety Features

 

Safety is a major concern on the shop floor as coils have become larger and heavier. Uncoilers have large, fast-moving parts, so operators must be trained on how the machine works as well as its correct setup.

Coils today can range from 33 to 250 kilopounds per square inch, and the uncoiler has been adapted to meet the demands in the yield strength of the coil. Heavier coils present bigger safety challenges especially when cutting the strap. Hold-down arms and snubber rolls are included on the machine to ensure the coil unwinds only on demand. The machine also can include feed-up drives and a side shift base to help centre the coil for the next process.

As coils get heavier, it becomes much harder to expand the mandrel manually. Hydraulic expanded mandrels and rotation capabilities are commonly requested as shops move operators away from the uncoiler for safety reasons and into other areas of the shop floor. Shock absorbers can be added to minimize uncoiler rotational abuse.

Depending on the process and speed, additional safety features might be required. These features include an outward coil retainer to prevent the coil from falling down, a monitoring system for the OD and RPM of the coil, and a unique braking system like water-cooled brakes for lines running at high speeds. These are all important to help ensure that when the roll forming process stops, the uncoiler also stops.

We are Uncoiler machine suppliers. Please feel free to contact us if you are interested in our products.

Pneumatic & Electric Ball Valve - How They Work

 Ball valves can be combined with a pneumatic actuator (pneumatic ball valves) or an electric actuator (electric ball valves) for automation and/or for controlling remotely. Depending on the application, automating with a pneumatic actuator vs an electric one may be more advantageous, or vice-versa. In this article, we will compare the two options. 

• Table of Contents
• Ball valve overview
• Actuator overview
• Pneumatic actuators
• Electric actuators
• Combining an actuator and a ball valve

 

Ball valve overview

 

 

A ball valve is a quarter-turn valve that controls the flow of a media by having a hollow rotating ball, as seen in Figure 2. The figure shows the main components of a manual ball valve in a sectional view. When the hollow portion of the ball is in line with the flow (pipe or hose), the valve is open and the media can flow through. The valve closes when the solid portion of the ball is in line with the flow, which is done with a 90-degree rotation (hence the name quarter-turn valve) of the ball.

It is also possible to position the valve between fully open and fully closed, which allows you to regulate the flow more precisely. Typical ball valves have two ports, one for an inlet and one for an outlet. However, three ports (L or T) are also available, and depending on how the valve is assembled and installed will determine how the 90-degree rotation of the ball directs the media flow. Four-port ball valves are possible but rare.

Ball valves have a valve stem, which is attached to the ball and controls its rotation. In Figure 2, the valve stem is connected to a manual handle to actuate the valve. However, the valve stem can also be connected to a pneumatic or electric rotary actuator to spin the stem to open and/or close the ball valve automatically and/or remotely.

 

Actuator overview

A valve actuator is a device that is used to remotely control a valve. If it controls a quarter-turn valve, the actuator is known as a quarter-turn actuator. Instead of a manual lever, you can mount an actuator on the valve to automatically and/or remotely control it. Actuators use a power source to generate the torque that is required to operate (rotate) a ball valve. For most actuators, the power source is either pneumatic, electric, or hydraulic (not discussed in this article). The difference in this power source makes different designs, which each have different advantages and disadvantages for certain applications (discussed below). Aside from the torque generating component, an actuator may have other features such as position indicators and manual override.

 

Pneumatic actuators

Pneumatic actuators control ball valves by the conversion of compressed air energy to mechanical motion. A rotary mechanical motion is required in a ball valve for a 90 degrees turn. Pneumatic actuator ball valves can be single-acting or double-acting. A single-acting pneumatic actuator uses a single compressed air input to turn the valve and a spring to return the valve to the normal position. A double-acting pneumatic actuator has two compressed air inputs to turn the valve and return the valve to the original position.

 

Operating principle

The most common mechanism for a pneumatic actuator for ball valves is the rack and pinion mechanism. This comprises of the rack (a linear gear) and the pinion (a circular gear) (figure 4). The rack is attached to a piston which is pushed by compressed air to achieve linear motion. This linear motion is converted to circular motion by the pinion. The pinion drives the stem of a ball valve to open and close positions.

To control the pneumatic actuator for ball valves, the compressed air is regulated by solenoid valves. Electrical signals from the controller energize the solenoid valve to either open or close positions allowing compressed air to flow through to both piston sides of the pneumatic actuator. The piston pushes the rack which turns the pinion connected to the stem of the ball valve.

 

 

Electric actuators

Electric actuators convert electrical energy into rotary force by the use of an electric motor to turn the ball valve through 90 degrees. They are energy-efficient, clean, and a quiet method of valve control. The electric motor can be powered by an alternating current (AC) or a direct current (DC). It is housed in a robust, compact housing that also contains other components of the actuator such as gearings, limit switches, wiring, etc. The whole assembly is connected to a valve through a compatible connection interface.

 

Operating principle

The electric motor generates a torque, which is transmitted by a shaft connected to the valve stem. This rotates the ball valve. To achieve the required torque, a system of gears is connected to the electric motor shaft. The torque capacity is an important specification for selecting an actuator. It must be higher than the required torque (breakaway torque) to turn the ball valve by a certain percentage often specified by the ball valve manufacturer. The breakaway torque is the minimum torque required to turn the ball valve usually in the fully closed or fully open static positions.

The speed of operation (the response time) of an electric actuator is inversely proportional to the torque of the actuator. The gear system defines the relationship between speed and torque. A higher gear ratio would result in more torque but a lower response time.

Electric actuators can be powered from a 12, 24, and 48V direct current and 24, 48, 120, 130, and 240V alternating current. Limit switches are installed to stop the current to the motor when fully closed and open. Electric motors can be used to carry out modulating control. This is used to accurately position the valve at any point between fully opened and fully closed positions (i.e. between 0° and 90°). This is useful for regulating the flow rate through the valve. A positioning circuit board (PCB) is installed in the electric actuator to modulate the electric motor. 

 

Combining an actuator and a ball valve

Although actuators and ball valves are separate components, they are most often used together. Therefore, it is more convenient to get them as a package to ensure conformity. Combining an actuator with a ball valve gives you an automatic ball valve that can be controlled remotely. The actuator and the ball valve have a connection interface to connect them. The connection interface comprises of a shaft, or stem, to connect the valve ball, and a flange to bolt the actuator to the valve. This interface may be brand-specific or standardized to standards. You can mount a brand-specific actuator on a compatible brand-specific valve. On the other hand, different ball valves and actuators can be interchanged as long as they follow the same standard.

 

Comparison between pneumatic and electric ball valves

The following are some of the comparable features of pneumatic and electric ball valves:

1) Rotation speed
The rotation speed is the speed at which the ball of an actuated ball valve makes a complete rotation (90-degrees). Typically for the same size units, the rotation speed of an electric ball valve is lower than that of a pneumatic ball valve.

2) Life span
The life span of equipment is the time that the unit is fully functional and operational. Pneumatic ball valves have fewer components and are easier to maintain; hence they have a longer life span than their electric counterparts. Electric actuators have several components that need maintenance, like the electric coil, electronic driver, mechanical actuator, etc.

3) Precision
Precision, or modulation, is for units that stop at a partially open point (i.e. 20-degrees open) to more accurately regulate the flow. Both pneumatic and electric actuators are precise in operation, but motorized ball valves have higher levels of precision. An electric ball valve is capable of opening and closing by very precise degrees. Pneumatic actuators carry out modulation by controlling the air pressure at the inlet port. Leaks or pressure fluctuations can easily affect the valve’s position. Electrical actuators, on the other hand, use exact electrical control signals to carry out control. Additional information can be found in our electrical modulating ball and butterfly valves article.

4) Energy consumption
Energy consumption is the energy required by the actuator to rotate the valve. In comparison, the energy consumption of an electric operated ball valve is less than pneumatic actuated ball valves. In pneumatic actuators, the entire air compression system (compressor, filters, lubricators, power, etc.) accounts for their high energy consumption.

5) Fail-safe
This is a safety feature designed to automatically open or close a valve in case of a power failure. It is typically easier and cheaper to feature a fail-safe mechanism on a pneumatic ball valve than on a motor actuated ball valve. Pneumatic acting actuators are very common and make use of a spring to return to the base position and are ideal as a fail-safe solution. Electric actuators with a fail-safe mechanism can operate with a battery or a spring and are usually more expensive than the pneumatic solution.

6) Cost
The cost of a pneumatic ball valve is usually lower than an electric one because the actuator design is less complex. However, this doesn’t take into account the costs of the components of the pneumatic system, such as the compressor, air preparation, pipes, etc. When no pneumatic system is available near the valve, usually electric actuation is preferred. The operation of a pneumatic valve is more expensive in the long run due to the higher energy consumption and energy losses that are a result of generating compressed air.

7) Position feedback
Position indicators indicate the position of the actuator at any given time. They are usually placed atop the actuator for high visibility. Most pneumatic actuators can be equipped with a limit switch on top for electrical feedback. Many electrical actuators have internal limit switches for position feedback. However, more basic actuators do not have this feature.

8) Size/torque range
Torque is the rotary force a ball valve requires to turn. Pneumatic actuators offer a much higher torque per unit size than electric actuators. Therefore, for applications requiring a large valve or high torque typically a pneumatic ball valve is a better option.

9) Hazardous conditions
An electric ball valve has to be NEMA/ATEX certified before it can operate in hazardous conditions. Pneumatic actuators, however, are more widely available with ATEX certification. Also, they neither generate nor are affected by electromagnetic disturbance. Unlike their electric counterparts, pneumatic actuators are not sensitive to wet environments, neither are they subject to overheating.

What Are Hydraulic Hose Rotary Joints?

 

Hydraulic hose rotary joint

 

Most hydraulics engineers are well aware that proper hose routing often means accommodating machine motion without overly stressing the hose, or letting it rub and abrade against other hoses or machine components. Otherwise, hose can prematurely fail, resulting in leaks, machine damage, downtime, costly environmental contamination and, potentially, a hazard to nearby personnel.

 

Swivel-type fittings are designed to allow the coupling and hose connection to rotate, which prevents twisting, kinking and excessive bending. That can extend hose life and reduce maintenance needs. It can also make for more efficient system plumbing. Using rotary joints can reduce the length of hose required between connections, eliminate the need for bent tubing to accommodate angled connections, and often can be connected directly to the hose line without adapters. Because swivel joints move, they can compensate for hose length changes when the system pressurizes and absorb hydraulic surges and shocks in a line.

 

Thus, many applications can benefit from the use of hydraulic hose rotary joints. These components permit an extensive range of articulation and movement in equipment operation and eliminate torque and twisting in hydraulic hoses. They can also simplify hose installation and maintenance.

 

Components

They consist of two major components, a stem and housing that can rotate relative to one another, as well as internal seals and bearings. Depending on the design, rotation can be unrestricted or somewhat less than 360°. Some rely on ball bearings to control movement, others have so-called ball-less designs with plain thrust bearings.

 

Types

Two basic types are in-line, where the opposing stem and housing fluid ports lie on a common axis; and 90° swivels, where the housing's fluid port is positioned to rotate on a plane 90° to the stem axis.

 

Hydraulic hose rotary joint

 

Applications

They are built to handle high pressures - often in excess of 5,000 psi - offer leak-free performance, resist hydraulic shock and side loads, and won't pull apart in operation. Over time the seals, back-up rings or bearings can eventually wear out, but many designs permit simple repair with seal replacement kits.

 

The swivel or hose should be mounted to the machine structure to ensure proper alignment and freedom of movement. While rotary joints are typically designed to allow free rotation with minimal friction, engineers should be aware that the weight of the attached hose, tubing or fittings - as well as the weight of the contained hydraulic fluid - may be substantial enough to place excessive side loads or bending moments on the swivel. The connection must be specified to handle such loads, or the seals may prematurely wear and leak. Side loading also causes excessive wear on the bearing surfaces and inhibits smooth swivel joint operation.

 

Hydraulic swivels are used in a wide range of rotary applications. Typical examples include grapples, forestry attachments, lift cranes and utility boom trucks, railroad maintenance equipment, demolition shears, and mobile excavators. And in this IoT era, special hydraulic rotary joints can be combined with electrical slip rings to transfer power or data signals. In addition to simple hydraulic swivels, a number of companies make rotary unions and rotating manifolds that transmit fluid from a single housing to multiple lines.

 

Design parameters

As with any other hydraulic component, engineers should consider a number of important design parameters. Swivel housings are available in steel and stainless steel, brass, aluminum and other common materials. Fluid compatibility with the specified materials is, of course, a must, and typical seal options include nitrile, ethylene propylene, neoprene and fluoroelastomer, to name a few.

 

Hydraulic hose rotary joint

 

Other considerations include pressure rating, internal flow characteristics and pressure losses, permissible rotational speed and torque requirements, SAE or ISO fluid ports options, and the ability to handle a range of ambient and fluid temperature ratings.

Many designs have an external exclusion seal to prevent ingression of contaminants, but it's always recommended to protect the swivel from dirt and abrasives whenever possible. For operation in harsh or corrosive conditions, a protective cover or elastomeric bellows are possible options.

 

And almost always, price is an important consideration. The cost of a rotary joint can be more than offset by cost-reduction benefits such as greater system design flexibility, improved system routing with less hose, simpler and quicker installation, fewer adapters and tube fittings, and longer service life.

 

We are a hydraulic hose rotary joint supplier. If you are interested in our products, please contact us now!