air compressor safety valve testing price

Conventionally when we talk about oil lubricated screw air compressor maintenance, it is mostly about replacing consumables such as filters and lubricant on time. While these consumables have a defined usable life and have a direct effect on the efficiency and the life of the air compressor itself when not replaced on time, there are a few critical valves in the air compressor that require maintenance as well. Compressor valves directly affect the efficiency, safety, and the functionality of the screw air compressor. Let us understand some of the commonly available valves in a screw air compressor, why they need maintenance, and discuss some of the frequently asked questions about screw air compressor valves.

A screw air compressor is very similar to a human heart. While a human heart has tricuspid, pulmonary, mitral, and aortic valves, a screw air compressor has four critical valves namely air inlet, minimum pressure, blow down, and safety valves.

Air inlet valve is also commonly known as the ‘Intake valve’ which is typically assembled on the airend’s intake. The air inlet valve of a conventional fixed speed screw air compressor controls the air intake into the compressor. It remains closed when the compressor starts to lower the starting load on the main motor and when the desired working pressure is attained in the compressed air circuit and thus enabling the compressor’s motor to run without any load. In some compressors that are capable of providing a variable output by modulating the amount of air it sucks in, the inlet valve holds various opening positions to regulate the volume of air entering the compressor. The effective performance of the inlet valve directly affects the compressor’s capacity and its power consumption during load and no-load conditions.

The minimum pressure valve is typically assembled on the exit of the air-oil separation tank of a compressor. The minimum pressure valve acts as a check valve preventing back flow of compressed air into the airend, retains a minimum pressure in the compressor system for lubrication, offers a restriction to avoid a collapse of the air-oil separation filter, and ensures a suitable velocity of flow across the air-oil separator that ensures efficient air-oil separation. The effective performance of the minimum pressure valve directly affects the compressor’s lubrication, air-oil separation efficiency, and power consumption during load and no-load conditions.

The blow down valve is typically found on a dedicated exhaust line from the air-oil separation tank. The blow down valve evacuates the compressed air in the air-oil separation tank each time the compressor runs on a no-load and when the compressor shuts down to ensure there is no back pressure when the compressor starts to load next time. The blow down valve of a conventional screw compressor is typically actuated by a solenoid valve. The effective performance of the blow down valve affects the compressor’s power consumption during un-load, capacity of the compressor when running on load, and the life of the motor.

The safety valve is typically mounted directly on the air-oil separator tank. The only function of the safety valve is to blow off the compressed air in the air-oil separation tank when the pressure in the air-oil separation tank exceeds the set pressure of the safety valve and there by prevents the tank from cracking under high pressure. A malfunctioning safety valve affects the safe operation of the air compressor or results in leakage of compressed air continuously.

Though each compressor manufacturer has their own unique valve design, compressor valves in general contain moving parts such as springs, valve plates, and plungers that affect the opening and closing of the valves and rubber seals / seats that offer perfect sealing when the valves remain closed. These moving parts wear or lose their mechanical properties over a period of time and the sealing components typically ‘age’ over time and lose their effectiveness and will need to be replaced.

Compressor manufacturers typically design these components to operate efficiently for several thousand or millions of operation cycles. However, several factors such as variability in the demand pattern, sizing of the air compressor against a certain air demand, the environment in which the air compressor operates, promptness of preventive maintenance, etc. determine how long these valves efficiently operate.

Many times, it is difficult to identify a malfunctioning valve or a valve operating with worn-out parts as the compressor continues to generate air. The typical symptoms of a malfunctioning valve are loss in compressor"s capacity, increase in power consumption during load or/and unload, drop in discharge pressure, increase in oil carry-over and more load on motor. These symptoms are either difficult to notice or have other frequently common assignable causes such as air leak before suspecting the compressor valves.

Case studies show that operating a screw air compressor with a worn-out / malfunctioning valve could increase its overall power consumption by 10 - 15%. Power cost contributes to more than 75% of the compressor’s total life cycle cost over ten years and hence this is a significant impact. Unserviced valves also lower the life span of downstream accessories by half. In some cases, a malfunctioning safety valve may result in a catastrophe.

Air compressor manufacturers typically offer convenient valve maintenance kits for customers that contain the internal parts of the valve that wear or age out. Changing the valve kits is a much more sensible and economical option than changing the complete valve.

It is difficult or almost impossible to identify a malfunctioning valve unless it is opened for inspection. Hence it is absolutely mandatory that these valves are inspected for effectiveness every year and the internal moving parts replaced as a part of preventive maintenance once every year or two depending on the operating conditions of the air compressor. It is typical for compressor manufacturers to mandate a valve kit replacement once every two years as a proactive measure.

In particular, the safety valve must be inspected and certified every year per the local safety laws to ensure they are functional and efficient. Sometimes, replacing the safety valve entirely with a valid certificate for one year is more economical as the certification procedures could be equally expensive on an existing valve.

As stated before, it is challenging to identify a valve that is worn out unless it is opened and inspected, but there are a few indicators that a qualified compressor technician can use to deduct a malfunctioning valve.

Low duty cycle operation: A sophisticated screw air compressor in today’s day and age carries a convenient microprocessor-based human-machine interface that keeps track of operating hours of the compressor under load and un-load conditions and the number of load/unload counts the compressor is subjected to over a period of time. A higher un-load hours and load/unload count indicates that the air compressor is oversized against the actual air demand. This in turn indicates the air compressor ‘cycles’ frequently between load and un-load mode as opposed to running continuously on load. Every time a compressor ‘cycles’, the inlet valve, blow down valve, and minimum pressure valve is brought into play where their internals ‘actuate’. Frequent actuation of these valves results in a faster wear of the internals and hence results in shorter life.

High operating temperature: A compressor that runs on a high operating temperature affects the life of the valve’s sealing components, which causes them to ‘age’ fast.

Compressor not building pressure: If the air demand has not changed over time and the facility is relatively free of any air leakage, the air compressor is probably not delivering the rated output. There is a high probability that there is a malfunctioning valve.

Increase in compressor’s power consumption: An increase in the air compressor’s power consumption profile over a period of time where there has been no abnormal change in the air demand and usage pattern indicates an increase in either the load or un-load power. There is a high probability that this is because of a malfunctioning valve.

Based on the design philosophy adopted by the air compressor manufacturer, the oil lubricated screw air compressors could have a few more valves that are critical to functional performance that must be maintained as well. Some of the other valves frequently used in an air compressor are as follows:

Temperature control valve (also known as thermal valve) is used to regulate the flow of oil through the oil cooler based on the operating temperature.

Drain valves are used to drain lubricant at the time of lubricant change over or cleaning. Air compressors equipped with a moisture trap at the outlet of the after cooler also has a drain valve (automatic or timer based) to discharge water collected.

The presence or absence of one of these valves and the type of actuation of these valves (electronic / mechanical) depends on air compressor’s design architecture. The Operation and Maintenance Manual (OMM) and the Piping and Instrumentation Diagram (P&ID) supplied by the air compressor manufacturer are excellent resources that explain the purpose, functioning, and maintenance requirements of these valves.

Many of the air compressor valves are highly specialized and exclusive. Their designs are usually complex and some even need special tools to service them. The internal components" build quality and material selection are extremely important and proprietary. Hence it is highly critical that only genuine valve kits issued by the air compressor manufacturer are used to maintain the valves. An inferior after-market replacement will most certainly compromise the performance of the entire compressor, void the original manufacturer"s warranty of the compressor, cause consequential damage to other parts of the compressor, and above all, be a safety hazard.

In conclusion, while it is important to change the screw air compressor"s filters and lubricants on time, it is equally important to perform preventive maintenance on these critical valves in a screw air compressor as recommended by the air compressor manufacturer. While the intake valve, minimum pressure valve, safety valve, and blowdown valve are critical to the performance and safety of the compressor, there could be other valves in the compressor that are critical and need maintenance. The air compressors sizing and the environment in which it operates are crucial factors that affect the life of the air compressor. Finally, it is critical to proactively service these valves using genuine kits issued by the compressor manufacturer to enable the air compressor performs efficiently and safely.

Gershom Joel has over 15 years of experience in the compressed air field and specializes in helping industries such as Pharmaceuticals, Textile, Electronics, and Food and Beverage find compressed air solutions to meet their unique requirements.  Gershom holds a Mechanical Engineering Degree from Anna University and a Masters in Business Administration from University of North Carolina.

ELGi North America, headquartered in Charlotte, NC, is a subsidiary of ELGi Equipments Limited, a leader in compressed air solutions for over 60 years. Established in 2012, ELGi North America, in conjunction with its subsidiaries, Pattons, Pattons Medical, and Michigan Air Solutions, offers a comprehensive range of compressed air products and services. Our product offering includes oil-lubricated and oil-free rotary screw and reciprocating compressors, dryers, filters, and ancillary accessories. ELGi and its subsidiaries serve multiple industry verticals spanning medical applications, pharmaceuticals, food & beverage, construction, manufacturing, and infrastructure. For more information, visit https://www.elgi.com/us/.

Maintaining the integrity of the pressure relief valve on an air receiver is absolutely essential when it comes to the on-going safe operation of a compressed air system. In this blog post we discuss what your responsibilities are as an owner of a pressure vessel (or air receiver) when it comes to maintaining its safe operation, and in particular what function the pressure relief valve serves and how to maintain its integrity.

An air receiver - or pressure vessel - is an important part of a compressed air system used to store compressed air as well as providing capacity during periods of peak demand. If improperly designed, installed, used or maintained, they can also be extremely dangerous and can lead to catastrophic outcomes such as fatalities, serious injuries and damage to property.

The ongoing condition monitoring of the vessel to ensure its safe operation, lies with the owner or operator of the pressure vessel. In accordance with the Standard AS/NZS 3788, depending on the size, design pressure and hazard level, an air compressor pressure vessel should be inspected externally every 2 years and internally every 4 years by a competent person.

One key component of an air receiver that needs to be inspected and certified on a regular basis is the pressure relief valve. Small but mighty, the pressure relief valve on an air receiver is a safety feature that effectively stops an air receiver from exploding if the pressure inside the vessel was to exceed its maximum allowable working pressure.

It achieves this thanks to its spring-loaded release mechanism. When the pressure inside the air receiver gets too high, the pressure pushes the pressure relief valve open allowing air to escape. Once the air receiver falls back below its maximum allowable working pressure, the pressure on the spring eases and the pressure relief valve will close. You can understand then, why maintaining the integrity of the pressure relief valve is absolutely essential for the on-going safe operation of the compressed air system.

Depending on the environment within which the compressed air system operates (for example if the compressed air system is located inside or outside), it is generally recommended that a pressure relief valve should be inspected every 12 months. Here an accredited inspector uses specialised equipment to test the functionality and effectiveness of the pressure relief valve.

In between that time - again depending on the compressed air systems operational environment - it is also generally recommended that the pressure relief valve should be manually checked for correct operation by a Competent Person. By manually lifting the valve (if possible) when the system is not pressurised, a Competent Person can check to make sure the spring is still intact and that there is not a build up of grime that could cause the valve opening to stick. Don’t forget though, that this is general advice only and you should always consult the OEMs operating instructions.

The pressure relief valve is just one area of an air receiver that needs regular attention to ensure the on-going safety of a compressed air system, but as you can see it is also a very important one. For further information and guidelines when it comes to air receiver testing and inspection click here or see the further resources section below.

Important: please note that only qualified and authorised personnel should perform maintenance tasks who have read, are conversant with and adhere to the safety instructions and section of the service manual applicable to maintenance of the piece of compressed air equipment.

KAESER AIR SERVICE Australia provides comprehensive pressure vessel inspection, testing and registration services. For more information or to request a quote phone 1800 640 611 or simply fill in the form below and we will get back to you.

Copies of valid "Permits to Operate" for air tanks, liquefied petroleum tanks or boilers are available from the Pressure Vessel Unit Headquarters Office for a replacement fee of $45.00. To request permit copies:

Click on the heading to access the searchable and printable pressure vessel database showing the current permit and inspection activities for all steam boilers, air tanks, and LPG tanks in the State of California.

Sullair’s spring-loaded safety valve is used as the compressor’s high-pressure shutdown protection function to ensure that the compressor stops before the safety valve is opened. This prevents the safety valve from opening and loss of lubricating oil when the compressor is running. out). The opening pressure of the spring-loaded safety valve has been set before leaving the factory, please do not change it without authorization.

The Sullair oil and gas separator tank is equipped with a Sullair spring-loaded safety valve. When the pressure in the tank exceeds the rated pressure of the safety valve, the safety valve will open automatically. The rated pressure of the safety valve has been set at the factory. For more safety, the monitoring system is generally set to shut down in the following situations:

If the spring-loaded safety valve is dirty and blocked, the safety valve cannot be opened or cannot be closed automatically after opening. If the safety valve cannot be opened, it will lose its function of protecting the pressure system, and the safety of the unit will not be guaranteed. If the spring-loaded safety valve cannot be closed automatically, a large amount of lubricating oil in the oil-air separator will spray out accidentally, causing property damage. Stop the machine every week to check the status of the safety valve.

Unlike those middle handlers who sell Sullair air compressors parts on Alibaba.com, Aliexpress, or Globalsources, eBay, Amazon, etc, Chengdu Pudding Mechatronic Co.CPMC has our own professional website.This helps save a big burden for overseas buyers, because third party platform like Alibaba or eBay, Amazon, Globalsources, etc charges high commission fee and system maintenance fee to their online agent. Here with CPMC, we are confident to offer 5-10% cheaper than any purchase on Alibaba.

Welded valves (on pipeline) can be tested on site, so there are no expenses for cutting, welding personal, weld inspectionsand time consuming procedures.

Testing report is printed immediately, containing all results, technical data & graphs, such as opening pressure, indication of closing pressure, quality (adjustment) of the spring, effect of the nozzle ring, and effect of the guide ring.

Curtiss-Wright"s selection of Pressure Relief Valves comes from its outstanding product brands Farris and Target Rock. We endeavor to support the whole life cycle of a facility and continuously provide custom products and technologies. Boasting a reputation for producing high quality, durable products, our collection of Pressure Relief Valves is guaranteed to provide effective and reliable pressure relief.

While some basic components and activations in relieving pressure may differ between the specific types of relief valves, each aims to be 100% effective in keeping your equipment running safely. Our current range includes numerous valve types, from flanged to spring-loaded, threaded to wireless, pilot operated, and much more.

A pressure relief valve is a type of safety valve designed to control the pressure in a vessel. It protects the system and keeps the people operating the device safely in an overpressure event or equipment failure.

A pressure relief valve is designed to withstand a maximum allowable working pressure (MAWP). Once an overpressure event occurs in the system, the pressure relief valve detects pressure beyond its design"s specified capability. The pressure relief valve would then discharge the pressurized fluid or gas to flow from an auxiliary passage out of the system.

Below is an example of one of our pilot operated pressure relief valves in action; the cutaway demonstrates when high pressure is released from the system.

Air pressure relief valves can be applied to a variety of environments and equipment. Pressure relief valves are a safety valve used to keep equipment and the operators safe too. They"re instrumental in applications where proper pressure levels are vital for correct and safe operation. Such as oil and gas, power generation like central heating systems, and multi-phase applications in refining and chemical processing.

At Curtiss-Wright, we provide a range of different pressure relief valves based on two primary operations – spring-loaded and pilot operated. Spring-loaded valves can either be conventional spring-loaded or balanced spring-loaded.

Spring-loaded valves are programmed to open and close via a spring mechanism. They open when the pressure reaches an unacceptable level to release the material inside the vessel. It closes automatically when the pressure is released, and it returns to an average operating level. Spring-loaded safety valves rely on the closing force applied by a spring onto the main seating area. They can also be controlled in numerous ways, such as a remote, control panel, and computer program.

Pilot-operated relief valves operate by combining the primary relieving device (main valve) with self-actuated auxiliary pressure relief valves, also known as the pilot control. This pilot control dictates the opening and closing of the main valve and responds to system pressure. System pressure is fed from the inlet into and through the pilot control and ultimately into the main valve"s dome. In normal operating conditions, system pressure will prevent the main valve from opening.

The valves allow media to flow from an auxiliary passage and out of the system once absolute pressure is reached, whether it is a maximum or minimum level.

When the pressure is below the maximum amount, the pressure differential is slightly positive on the piston"s dome size, which keeps the main valve in the closed position. When system pressure rises and reaches the set point, the pilot will cut off flow to the dome, causing depressurization in the piston"s dome side. The pressure differential has reversed, and the piston will rise, opening the main valve, relieving pressure.

When the process pressure decreases to a specific pressure, the pilot closes, the dome is repressurized, and the main valve closes. The main difference between spring-loaded PRVs and pilot-operated is that a pilot-operated safety valve uses pressure to keep the valve closed.

Pilot-operated relief valves are controlled by hand and are typically opened often through a wheel or similar component. The user opens the valve when the gauge signifies that the system pressure is at an unsafe level; once the valve has opened and the pressure has been released, the operator can shut it by hand again.

Increasing pressure helps to maintain the pilot"s seal. Once the setpoint has been reached, the valve opens. This reduces leakage and fugitive emissions.

At set pressure the valve snaps to full lift. This can be quite violent on large pipes with significant pressure. The pressure has to drop below the set pressure in order for the piston to reseat.

At Curtiss-Wright we also provide solutions for pressure relief valve monitoring. Historically, pressure relief valves have been difficult or impossible to monitor. Our SmartPRV features a 2600 Series pressure relief valve accessorized with a wireless position monitor that alerts plant operators during an overpressure event, including the time and duration.

There are many causes of overpressure, but the most common ones are typically blocked discharge in the system, gas blowby, and fire. Even proper inspection and maintenance will not eliminate the occurrence of leakages. An air pressure relief valve is the only way to ensure a safe environment for the device, its surroundings, and operators.

A PRV and PSV are interchangeable, but there is a difference between the two valves. A pressure release valve gradually opens when experiencing pressure, whereas a pressure safety valve opens suddenly when the pressure hits a certain level of over pressurization. Safety valves can be used manually and are typically used for a permanent shutdown. Air pressure relief valves are used for operational requirements, and they gently release the pressure before it hits the maximum high-pressure point and circulates it back into the system.

Pressure relief valves should be subject to an annual test, one per year. The operator is responsible for carrying out the test, which should be done using an air compressor. It’s imperative to ensure pressure relief valves maintain their effectiveness over time and are checked for signs of corrosion and loss of functionality. Air pressure relief valves should also be checked before their installation, after each fire event, and regularly as decided by the operators.

Direct-acting solenoid valves have a direct connection with the opening and closing armature, whereas pilot-operated valves use of the process fluid to assist in piloting the operation of the valve.

A control valve works by varying the rate of fluid passing through the valve itself. As the valve stem moves, it alters the size of the passage and increases, decreases or holds steady the flow. The opening and closing of the valve is altered whenever the controlled process parameter does not reach the set point.

Control valves are usually at floor level or easily accessible via platforms. They are also located on the same equipment or pipeline as the measurement and downstream or flow measurements.

An industrial relief valve is designed to control or limit surges of pressure in a system, most often in fluid or compressed air system valves. It does so as a form of protection for the system and defending against instrument or equipment failure. They are usually present in clean water industries.

A PRV is often referred to as a pressure relief valve, which is also known as a PSV or pressure safety valve. They are used interchangeably throughout the industry depending on company standards.

Oil-free air compressors are powerful equipment leveraged in several industries. A comprehensive maintenance system is essential when you want to protect your investment and processes.

Oil-free air compressors are excellent air compressor models because they prevent oil from getting into the compressor components and therefore disrupting operations. However, they still require servicing and inspecting to ensure parts and processes work as they should. Regular maintenance is necessary for optimizing your oil-free compressor life expectancy.

To assess your safety valve’s functionality, run your air compressor until it reaches the shut-off pressure. At this point, pull out the valve ring. This action will produce three reactions that require different responses, including:

The valve closes automatically and releases pressure: If you get this reaction, your safety valve is operating regularly. You can move on to your next test and mark that the component is functioning.

The valve fails to close: If it doesn’t return to its original position after pulling it out, it is time to replace it. You will need to shut down this air compressor and mark that it is out of operation until repairs are complete.

The valve fails to release pressure: Along with closing automatically, the safety valve must release tank pressure. If the pressure remains after pulling it out, that is another indicator that the safety valve needs replacing. When inspecting your safety valve, you might get one failure or both.

Vapor and condensation build up in tanks because of the moisture found in the air. To ensure air compressor and component functionality, you need to drain the tank frequently and regularly to prevent too much buildup.

The filter’s condition will determine its air quality. The air compressor’s filter prevents contamination from passing through processes, making it an integral component. You should check the air filter depending on your operations and scale.

Note that air filters fail quality tests if they show signs of dirt, buildup, wear or other damage. These factors make it harder for the filter to work correctly, requiring you to make them for repair or replacement.

Air filters can come in several materials, including paper, felt and foam. The paper and felt options are consumables and need replacing if they do not pass quality tests. Alternatively, you can wash foam air filters and replace them in your equipment once they are thoroughly dry.

During your regular maintenance, inspect the power cord’s quality. Fraying or other damages can create an unsafe operating environment for equipment and employees. If you notice wear, shut down the equipment and contact an electrician to start the repair process.

Like the power cord and air filter, you can assess many industrial oil-free air compressor components by simply looking at them, making maintenance procedures straightforward and efficient. Some parts you should check when inspecting your air compressor include the following:

With these components, look for signs of damage and wear, such as cracks. Some fittings might need tightening, while other parts will require replacing. Additionally, review the air tank for any holes or rust. You must replace the tank if you notice any wear or damage. You cannot repair this component.

Repairing and replacing parts can become costly, especially when some components wear quickly. Running tests might take away from essential operations. Finding the balance for maintenance frequency is vital to creating a cost-effective solution.

Reducing downtime: When you can better ensure equipment functionality and quality, you can prevent extended downtimes that hurt operations and overall efficiency. Regular maintenance catches problems early, resulting in less extensive repairs that take less time to complete. Quality and operational components and systems mean you can enhance optimal performance.

Preventing costly repairs: More comprehensive maintenance costs more than fixing smaller parts. Additionally, replacements might be more expensive than repairing existing systems. Regular maintenance allows you to identify wear and damage at smaller levels before they affect other components and systems. Even one component underperforming or working with damage can hurt other parts in the air compressor.

Improving energy efficiency: Operating more efficiently can reduce your energy bill. Equipment functioning with damaged or worn parts might overcompensate and use more energy than it needs to meet the same specifications. Maintenance and servicing can identify overproduction before the air compressor uses large amounts of energy.

Developing a proper lockdown procedure: When an air compressor fails a test or inspection, you need a way to communicate to other employees that it is inoperable until fixed. Lockdown procedures prevent equipment from starting up. Applying locks to startup processes and components prevents employees from powering on air compressors, while bright tags indicate they should not use them.

Acting at regular intervals: As you establish your maintenance habits, you must determine how often you will carry out procedures. Some tests and checks might need higher frequencies, like daily or regular intervals, while others can wait for a more comprehensive annual review. Each air compressor has unique schedules depending on its make, model and age. Finding a schedule that works for your organization and equipment will better optimize your efforts.

Keeping maintenance and servicing records: You can identify potential problems sooner by tracking equipment repairs and replacements. Charting actions taken allows the next inspector to ensure problems have not returned or replacements work well. It can also highlight when equipment costs offset its performance and might be time to invest in a newer model.

At Quincy Compressor, we value reliability, efficiency and productivity. When maintenance and servicing are essential for improving performance and equipment life span, partnering with the right organizations helps streamline the repairs and replacement processes.

Quincy Compressor offers several service plans, allowing your company to meet your needs with quality maintenance and repair opportunities. With these plans, you can receive excellent care from trained experts who know what to inspect and provide top-grade solutions.