Tubing type

Tubing and hose may seem to be the same, but tubes are designated by their external diameter so as to be compatible with push-to-connect fittings. Hose is designated by its internal diameter, and usually comes with rigid, swivel or quick-disconnect fittings that are attached at both ends. Pipes are entirely rigid, constructed from a single solid material and usually defined by their internal diameter dimension.

Tubes are relatively rigid vessels generally made from one solid material, typically some kind of thermoplastic, which can also be internally reinforced for higher strength:

• Nylon is light, tough and dimensionally stable, with low water absorption and high resistance to flexural fatigue.

• Polyurethane is flexible, strong, resistant to abrasion and kinks and can also withstand contact with oils and fuels.

• Polyethylene and high density polyethylene (HDPE) are widely resistant to solvents and chemicals, and relatively cheap with good flexibility.

• Polypropylene withstands UV radiation, is resistant to chemical attack and can be formulated for use in food-contact applications.

• PVC and CPVC (chlorinated polyvinyl chloride) is light and usually more flexible than polyethylene or nylon, with a good resistance to chemicals, and can sustain repeated sterilisation. It is also usually transparent, enabling visual confirmation of flow.

Hoses are completely flexible vessels constructed from a variety of the same thermoplastic materials. An inner tube is reinforced with one or more layers of spiral-wound or braided fibres, with a protective outer cover. Hose is generally more expensive than tubing but is more rugged and durable, as it is often used for manual tools and gets dragged across abrasive surfaces.

 

from Internet

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Post time:        Apr-02-2022

One of the important parts of the pneumatic components is the cylinder. In order to ensure the normal use of the cylinder and avoid unnecessary situations, for the use of the pneumatic components and cylinder, let’s check the right way to use cylinder.

cylinder  

When using the cylinder, the air quality requirements are very high.  Clean, dry compressed air should be used.  The air should not contain organic solvents, synthetic oils, salts, corrosive gases, etc., in order to avoid bottle and valve failure.  Before installation, the connecting pipe should be blown out completely, and impurities such as dust, chips and fragments of sealing strip should not be brought into the cylinder valve.  In places where is with more dust, water drops and oil drops, telescopic protective cover should be installed on the side of the rod, to avoid the rod twisting during the installation.  strong dust rings or waterproof cylinders should be used when telescopic sleeves are not available.

Standard cylinders should not be used in corrosive fogs or in fogs that inflates seal rings.  The grease lubricating cylinder should be equipped with reasonable lubricator flow, do not lubricate the cylinder with oil, because the cylinder is filled with grease in advance, which can be used for a long time. This type of cylinder can also be supplied with oil, but once the oil is supplied, it cannot be stopped because the pre-lubricated grease may have been flushed away and insufficient oil supply will cause cylinder failure.  

The installation position of the cylinder should prevent drilling cuttings from mixing into the air inlet of the cylinder.  Cylinders should not be used as liquefied gas cylinders to avoid oil leakage.  The sliding parts of the cylinder and the piston rod shall not be damaged to avoid air leakage and damage to the piston rod seal ring caused by improper operation of the cylinder.  Compensating valve should have enough space for maintenance and adjustment, electromagnetic switch should have enough space for installation and adjustment.  If the cylinder is not used for a long time, it should be operated once a month and protected with oil to prevent rust.  

REED SENSORS

Reed sensors have been in use for many years and are the most common type used in pneumatic cylinders. They're cost-effective and versatile, although typically slower and less resistant in extreme environments.

How Does A Reed Sensor Work?

A reed switch is a simple form of magnetic proximity sensor, comprising a pair of ferromagnetic nickel and iron reeds mounted axially inside a hermetically sealed glass tube. When no magnetic field is present, the metal reeds remain separate, in the OFF position. As the cylinder-mounted magnet approaches, the sensor generates a magnetic field parallel to it, switching to the ON position when a strong enough magnetic field attracts the metal reeds together.

Reed sensors usually last for at least 10 million switching cycles, and they're inexpensive to acquire and install. They can function with either AC or DC electrical loads and require no standby power.

Conversely, they're comparatively slow, and may not work well with high-speed applications. As they're mechanical devices that contain moving parts, they will eventually fail after a finite number of switching cycles. Using them with high-current loads will also reduce their life expectancy. The main concern for reed switches is that they can be unstable in applications that deliver high shock and vibration frequency.

ELECTROMAGNETIC SENSORS

There are three types of electromagnetic sensor:

• Anisotropic Magnetoresistive (AMR)

• Giant Magnetoresistive (GMR)

• Hall-Effect (HE)

These are solid-state devices that use semiconductors instead of mechanical parts. This makes them easier to mount, faster to react, longer-lasting and more resistant to vibration and shock.

How Do Electromagnetic Sensors Work?

Electromagnetic sensors work by transforming a measurable physical quantity into an electrical output signal. An HE sensor has a continuous electrical current flowing through a semiconductor. A radial magnetic field applied to the sensor causes the charged electrons within it to separate, and induce an output voltage across the HE circuit. The sensor is switched to the ON position when this voltage exceeds the switching threshold.

AMR and GMR sensors can apply a magnetic field either axially or radially, changing the electrical circuit's resistance properties to create a higher voltage gradient as the magnetic field increases.

These types of sensor are fast-acting, have no mechanical parts to wear out, and are much more resilient to shock and vibration. They're less sensitive than HE sensors and can detect weaker magnet fields, allowing better detection of piston movement over greater distances. AMR sensors are cost-competitive and more compact than reed switches, while GMR sensors are even more sensitive and can be even more compact. This makes them a good choice for smaller or shorter cylinders.

AMR sensors usually draw current continuously and are not so well suited to low-power applications. The high sensitivity of GMR sensors is beneficial for applications requiring immediate sensor feedback, but they may be disturbed by nearby magnetic fields of other machinery and thus cause unintended output signalling.

Choosing A Pneumatic Cylinder Sensor

Reed sensors are still the most popular and will work for most common applications. Their technology has worked well over time, and their life cycle and vibration resistance have mostly been adequate. For more specialised applications, you'll need to take into account what environment your cylinder will be exposed to. Factors include the use of enclosed clean environments, extremes of temperature, and vibration and shocks.

For solid-state devices, you'll need to consider whether the output switching speed is critical to your application, and what output signal type your control system requires: PNP (positive) or NPN (negative).

The type of sensor you choose must have current requirements and switching power compatible with your control system. It must also incorporate any necessary circuit protections. You'll need to take mounting options into account according to your cylinder type, and magnet orientation to the piston if you choose a reed switch or HE sensor.

The final consideration is the power supply wiring to the sensor, as miswiring the sensor can permanently damage it. Solid-state (AMR, GMR, HE) sensors usually have a three-wire configuration; reed switches use two-wire.

Solutions & Considerations

Most people will go with a reed switch sensor for the usual run of machine applications, but more complex applications and automated systems may demand a more responsive solution. Considerations of space, power and responsiveness will all depend on its working environment, while cost-effectiveness is always a factor.

（From the internet）

Solenoid valve selection guide

Before choosing a type of solenoid valve, sufficient information about the application must be gathered. This guide describes the key parameters for solenoid valves.

Important Information

These are the most important guidelines when selecting a solenoid valve. Keep these guidelines in mind before choosing a valve.

• Solenoid valves are very sensitive to dirt and only work with clean liquids or air.

• Note that indirectly controlled solenoid valves require a permanent pressure differential of around 0.5 bar to function properly. Therefore, you can not use indirect operated valves in a closed circuit or systems with a low inlet pressure. Direct and semi-direct operated valves operate with a pressure differential from 0 bar.

• Make sure that the used medium and temperature are compatible with the materials of the valve, such as body and the seal materials.

• Solenoid valves open and close fast (between around 10 and 1000 ms). Improper use can cause pressure transients in the system (water hammer).

Principle of operation

There are different types of solenoid valves, each with different principles of operation:

• Direct operated (operating from 0 bar)

• Semi-direct operated (operating from 0 bar)

• Indirect operated (pressure differential required, normally at least 0.5 bar)

It is important to choose the right operation principle. Direct operated valves operate from 0 bar. In the valve there is a small orifice which is sealed off by a plunger with a polymer gasket. If the solenoid (electromagnet) is electrically energized, the plunger is lifted by the electromagnetic force and the valve opens. This principle is often used for small valves and is suitable for small flow rates. For larger flow rates, a semi-direct or indirect operated valve is recommended. Both make use of the medium pressure to open and close the valve. Semi-direct operated valves operate from 0 bar and often have a more powerful coil than indirect operated valves. Indirect operated valves need a permanent pressure differential of around 0.5 bar for proper operation. The advantage of indirectly operated valves is that they usually can control large flows with a relatively small coil and thereby have a reduced energy consumption.

Check if there is a permanent pressure differential over the valve of at least 0.5 bar. In this is the case, an indirect operated valve may be chosen (a semi-direct valve is of course also allowed in this case). If this is not the case (low inlet pressure, closed circuit, ..), choose a (semi-)direct operated solenoid valve.

 

from Internet

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Post time:        May-03-2022

In order to further implement the security work and improve the emergency handling capacity of the company’s production staff, At  4 PM on May 21, BLCH Pneumatic Technology Co., Ltd. carried out fire emergency drill and training, and invited Yueqing Antong Safety Technology Service Co., Ltd. to participate in the on-site guidance.

Urgent notice: “the company first floor waste warehouse fire!”As the fire control room alarm sounded, the fire drill officially began.

The security team quickly closed the fire surrounding, and call 119 for support; The evacuation team guided the personnel to immediately implement the fire fighting, and finally the fire was under control, and the on-site personnel  were transferred in time. During the exercise, each teams responded positively, their responsibilities were clear, and the exercise procedure was well organized and orderly.

After the fire drill, we organized to learn the early fire fighting knowledge evacuation and escape knowledge and fire extinguishers and other fire equipment  correct operation method on the site.

The fire emergency exercise fully enhanced the awareness of fire safety of all the staff of the company, strengthened the knowledge of fire safety and the actual combat skills of the correct use of equipment.

 

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Post time:        May-23-2022

Cylinder Accessories

Even when a cylinder is sized properly, it may stroke too fast and require use of a flow control, typically by controlling flow of air leaving the cylinder. This also reduces noise problems caused by cylinders banging and reduces rapid exhaust racket. These flow controls are typically mounted directly to the cylinder, but can also be mounted inline near the cylinder, or at the valve if the hose between the valve and cylinder is less than about 3 feet.

Specifying cylinders with built-in cushions can help provide long-term performance in high-speed pneumatic motion applications. The cushions allow a cylinder to stroke at high speed and only slow down near the end of stroke for a quiet, low-impact stop. Adjustable pneumatic cushions are often the best solution, comprised of specially designed end caps with built-in flow controls. Mufflers can also be used to quiet cylinder or valve exhaust noise, and they are often a simple and low cost solution.

Cylinder position switches are extremely helpful in sequencing operations and prevent starting the stroke of one cylinder before the previous cylinder’s stroke is complete. Using timers to control a sequence instead of position sensors should be avoided in this and most cases. One stuck or slow cylinder during an automated sequence can cause a machine crash, costing much more than the cost of buying, installing and programming end-of-stroke sensors.

These are just a few of the many items to consider when designing a successful pneumatic system. Other factors, such as energy efficiency, can affect overall system design as well. But regardless of the design, watch out for the common issues and always be sure to supply, prep and distribute the air properly. When properly applied, your pneumatic devices and actuators will have a long life with limited operational issues along the way, and with minimal required maintenance.

These are just a few of the many items to consider when designing a successful pneumatic system. Other factors, such as energy efficiency, can affect overall system design as well. But regardless of the design, watch out for the common issues and always be sure to supply, prep and distribute the air properly. When properly applied, your pneumatic devices and actuators will have a long life with limited operational issues along the way, and with minimal required maintenance.

Control Valves

Once the cylinders are selected, you should now have a good idea of the flow rate and pressure of compressed air needed. With this information, you can select control valves. Items to consider in valve selection are size (flow capacity), type and actuation method.

Choosing the right type of valve for the job required is not as difficult as it may seem. For cylinder control, the simplest method is to use a 3-way valve for a single-acting cylinder and a 4-way valve for a double-acting cylinder. Systems can be much more complex if needed, but let’s focus on a basic system for now. The form factor of the valve can vary a great deal and many people have a variety of preferences. It’s usually best to make sure the valve has the needed performance characteristics before locking into a particular form factor.

Valve Sizing

Once the function of the valve has been determined, look at the required flow capacity. The usual first step is to use the air cylinder bore, stroke and cycle rate to determine a flow rate in standard cubic feet per minute (SCFM). Many valve suppliers will list a flow rate at a particular inlet pressure and pressure drop. Others will list this value as a factor Cv, which has no units. For a more thorough explanation, check out our Interactive Cv Calculator here. A simple thing to remember is that a larger Cv value will allow a higher flow rate of air through the valve. Key points to remember in valve sizing are that undersized valves may restrict flow and not allow a system to work properly. Oversized valves often cost more and will use more air. Keep in mind that air consumption is a major portion of the expense for a pneumatic system. If air consumption is a major concern for your factory, check out our Interactive Air Consumption Calculator here.

Valve Actuation

How will the valves be operated? Manual valves could be push button, lever or foot pedal activated. The more common method is to use electric solenoids to operate the valve. Solenoids are available in a variety of both AC and DC voltage ratings to fit just about any need. Match the solenoids up with your electrical control system. In less common situations, an air piloted valve may be required. When air pressure is applied to a pilot port, the valve switches. This is a good way to switch very large valves while using very little electrical power – use a small solenoid valve to send air to the pilot port of the large valve.

(FROM INTERNET)

One of the important parts of the pneumatic components is the cylinder. In order to ensure the normal use of the cylinder and avoid unnecessary situations, for the use of the pneumatic components and cylinder, let’s check the right way to use cylinder. When using the cylinder, the air quality requirements are very high. Clean, dry compressed air should be used. The air should not contain organic solvents, synthetic oils, salts, corrosive gases, etc., in order to avoid bottle and valve failure.