valve Archives - Page 2 of 3

Avoiding Common Risks in a Propane Transfer

Posted on May 27, 2016December 31, 2018 by Vitalii Prokopiv

In terms of energy usage, propane makes up less than 2 percent, but it is still a potential source of danger if you are not exceedingly careful when handling it. This hydrocarbon is used commonly for cooking and heating, but it is one of the most flammable chemicals. This makes it easy to use for such activities, but it also means that it should be handled cautiously. A propane transfer is something you might need to do for several reasons, but when you do, there are a number of risk factors you should be aware of before you begin. This guide can help you avoid some of the mistakes that most often lead to injury and accidents.

Understand the Risks Propane Can Pose

Propane has no odor nor no color, so you will not have a way of immediately identifying it. It does, however, pose risks that you need to be aware of. Propane acts as an asphyxiate. This means that it can deprive your body of oxygen and result in any of the following injuries:

Suffocation
Cardiac arrest
Seizures
Frostbite
Migraine
Damage to nerves

These are the symptoms that may occur after highly concentrated quantities of propane are released. Signs of lesser exposure include numbness, nausea, congestion, hallucinations and hyperventilation among other various symptoms. It is important to understand these risks so that you can seek immediate help if you begin to suspect you have poisoning from the propane.

Consider Whether It Is a DIY or Professional Job

Depending on what purpose you are attempting a propane transfer for, you may or may not need to call a professional to complete the task for you. It is never a bad idea, but many people do propane transfers in order to move the chemical from a large and unwieldy tank into a smaller and more compact one. Since propane can take the form of either a gas or a liquid, you can heat the larger tank so that the propane vaporizes and cool the smaller tank so that it liquefies, transferring the chemical through a hose connecting the two containers.

Use the Right Tools

If you have decided to attempt a propane transfer, you will need the following supplies:

Two tanks of different sizes
POL fittings
Dual-sided hose
Warm and cold water to control temperature

These supplies will allow you to attempt the propane transfer at home, but as is noted above, you should proceed with caution. The process may take a long time.

Trust Professional Expertise When Necessary

Even if you use all of the right tools and precautions, you will likely not be able to perform a basic propane transfer the way a professional can. If the project surpasses your expertise, a professional with a flow meter can help you. What function does a flow meter serve in this context? It provides information regarding the flow and pressure of the propane, so any risks such as leaks can be detected early. This can be an invaluable resource for people who need to transfer a chemical but don’t want to take the risk of personally attempting it at home.

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Bearing Life from Materials and Design

Posted on May 23, 2016January 10, 2019 by Vitalii Prokopiv

Rotating process machinery depends on bearings, either rolling element bearings or fluid film bearings. These parts counteract gravity to keep the shafts moving as freely as possible without wear or excessive maintenance. The characteristics of each type of bearing leads to the maintenance, life span, and type of load possible for the application.

Babbitt is a widespread material for bearings. It allows for smooth start-up and shut-down while offering conform-ability and embed-ability reducing damage to the spinning shaft. Babbitt bearings must be limited to a maximum temperature of 130°C or warping may lead to misalignment. Bronze can be a substitute for Babbitt bearings for higher temperature applications but can be damaged more easily by contaminants.

Fluid film bearings depend heavily upon their design, and application specific designs can be highly specific. An operating pressure must be developed in the fluid to counteract gravity. Bearing clearance, the difference between the bearing bore and shaft diameter, greatly affects dynamic performance from temperature changes and power loss. Even the manner in which lubrication is introduced into the bearing can drastically change the performance. A flooded bearing will have higher power losses and operating temperatures than a directed lubrication bearings.

Click here for the full article from Processing Magazine.

New Compressors Breathe Life into Water Treatment Plants

Posted on May 19, 2016January 10, 2019 by Vitalii Prokopiv

Air supply is critical in many industries, sometimes surprisingly. Water treatment facilities are not the first buildings where one would expect air supply to vastly affect efficiency.

In water treatment plants for the Rubiera system, the process is built into four parallel pipelines, and compressors are used during the oxidization and nitrification portions of the process. The initial setup used compressors rated for much more capacity than was required by the facility, and as such the process was over-supplied for long periods of the day.

“The first step was to change the set-up, linking all the machines together. It was seen, in fact, that it would have been sufficient to use only one compressor for generating the process air during the period of less demand, but that compressor had to be very versatile and offer a wide range of capacity variations.”

Click here for the full article from Process Worldwide.

Precision Volume Pumps

Posted on May 18, 2016 by Vitalii Prokopiv

For when you need an exact amount of fluid moved from one spot to another, precision pumps will disburse exactly what you need when you need it. The two categories of precision dosage pumps are piston and diaphragm pumps.

Piston Pumps

These types of pumps are designed for continuous flows against a multitude of pressures, even upwards of 1000 Barg. A piston inside the pump recirculates up and down with seals to prevent leaks and create suction.

Diaphragm Pumps

Diaphragm pumps utilize a plastic membrane or multiples of membranes to create a vacuum and discharge the fluid. Because there is no direct contact with the pumping mechanics, these pumps are situated well for toxic, harmful, or abrasive fluids.

Click here for the full article by Amin Almasi.

Valve Flow Characteristics

Posted on May 17, 2016 by Vitalii Prokopiv

In selecting a valve for use plenty of characteristics must be suitable for your desired application. Readers recently asked Béla Lipták some questions regarding control valves and their characteristics. Some of the questions and answers are presented below. The complete list can be found at the link below.

What are the definitions of wide and small ranges in terms of flow turndown?

A control loop will be stable if its gain does not change with variations in the load. The loop gain is the product of four gains (process, controller, sensor, valve) and, ideally, it should stay constant at about 0.5. If the process gain varies with load and the sensor and controller gains are constant, the ideal valve characteristic is one that will compensate for the variation in process gain, so that if the process gain rises with load, the valve gain drops (equal percentage); if the process gain drops with load, the valve gain rises (quick opening) and if the process gain remains constant, the valve gain should also be constant (linear).

How would I go about measuring flow of hydrocarbons with 1% sand by mass included?

Either Coriolis or vortex can wear at a rate proportional to the percentage of sand in the flow, and both meters could have a short lives. Sharp-edge orifices are similarly vulnerable. The choice is affected by flow rate and pipe size.

I would worry about any Coriolis flowmeter with a relatively thin metal wall. Magnetic, ultrasonic and flow nozzles have been recommended. With a sufficiently high flow rate, an elbow meter will also work. Any DP meter might need a chemical seal or liquid purge to avoid plugging.

Click here for the full article on Control Global.

Fluid Flow Determines Pumps and Fittings

Posted on May 11, 2016 by Vitalii Prokopiv

Given a specific set of characteristics for a fluid and the flow requirements of the system, pumps and fittings can easily be selected. Each pump is designed for a specific flow rate and head pressure, and fittings are built for specific applications. These optimized points are called best efficiency points, BEPs.

Common practice is to select a pump with a BEP slightly higher on a system pump curve than the situation calls for. While this practice is conservative, and avoids pumps stresses from impacting longevity, systems can use pumps slightly underrated for the application without worry. If the operating requirements are too far away from the pump BEP, vibrations can cause early failure.

“Selecting a pump that will operate near the minimum flow limits is just as risky as choosing one that will operate at the end of the curve.” –Pumps&Systems

Click here for the full article by Jim Elsey.

Maintenance for Optimum Bearing Performance

Posted on May 9, 2016 by Vitalii Prokopiv

Bearings reduce friction between two moving surfaces, and from that job they wear down and eventually break. To best keep bearings rolling for as long as they can, some maintenance is required in various parts of the lifespan.

Before Installation

Bearings are shipped and stored with a thin layer of manufacturing oil to preserve the bearing. If this coating is wiped off, smudged through handling, or dries out the bearing can rust or the lubrication can become useless. While storing bearings make sure to keep the bearing coated with preservative oils.

During Installation

Bearings are designed to have an interference shaft fit on the shaft during application. This fit is built into the dimensions and is accounted for. If a bearing is installed onto a shaft too big or too small, the difference in clearance can wear the bearing much quicker than specified.

Proper lubrication is necessary to reduce heat, and friction within the bearing itself. Due to the properties of lubricating oils, bearings may leak and can be sealed by silicone rings or sealing grease.

Ongoing Maintenance

Through continuous use of bearings, lubricating greases and oils with wear out just as much as the interior rollers in the bearing. Properly replacing and refilling the lubricant of a bearing will extend the life of the bearing. Some manufacturers provide charts for re-greasing intervals, check with the OEM of your bearing for details.

Click here for the full article by Mike Pulley.

Pump Submergence and Air Entrainment

Posted on May 5, 2016 by Vitalii Prokopiv

Fluid pumps are specifically designed to optimize the flow of fluids through the systems they are connected to with as little non-condensable gases as possible. Air trapped in the fluids can cause cavitation at higher flow rates that damages pump internals as well as pipe seals and joints. For these reasons the proper depth to submerge pumps is pivotal to prevent as much air from flowing through a pump.

As the velocity of the fluid flowing through a pipe increases the depth required for a pump pushing the same rate of flow increases. Because velocity increases as pipe diameter decreases and flow rate remains static, if the same pump is connected to a smaller pipe, the input source for the pump needs to be deeper to prevent vortices from forming. If the source tank is too shallow to allow for this minimum submergence other methods like suction bells and barriers can be introduced to lengthen the travel distance of the fluid to the suction inlet of the pump.

As a general guideline, 2 percent free air will reduce pump flow by 10 percent, and 4 percent air will reduce the flow by more than 40 percent. The average pump will likely fail to operate at 14 percent air entrainment. Some pump designs that use vortex impellers, recessed impellers, separation chambers or air escapes can handle air entrainment up to 24 percent.

The recommended suction velocity for pumps is between 5 and 8 feet per second, with a suggested maximum of 6 feet per second unless suspended solids or fluid characteristics demand faster flow rates.

Click here for the full article on Pumps&System.

Pumping Liquids with Dry Gas Seals

Posted on May 3, 2016 by Vitalii Prokopiv

During the processing of natural gas liquid ethane is pumps from 28 bar vessels to 76 bar vessels, and while under normal temperatures this can be done easily, Texas summers regularly reach temperatures where ethane vaporizes and creates product loss. Most seals for these systems use a liquid-lubricated seal, but under varying pressures these can warp and leak. Different variations of this type of seal use an inert gas between one or more pressurized faces to prevent leaks, but once the liquid reaches a higher vapor pressure the now gas breaches the seal.

Dry gas seals are simple albeit unconventional in liquid pumping situations. Seals are normally designed for non-contact operation, meaning any turning, ratcheting, or other operating situations can cause wear and eventual failure. Dry gas seals feature a crystalline layer simulating natural diamond to resist chipping and flaking. Furthermore by using an inert gas as the holding pressure, any vaporized ethane must combat a higher pressure to escape.

The increased structural resilience and absence of mechanical contact make these types of seals longer lasting, up to 5 years rather than 3 weeks in this circumstance.

Click here for the full article on Pumps & Systems.

HMIs Deliver More Detail and Accuracy

Posted on May 2, 2016 by Vitalii Prokopiv

Human-machine interfaces are the terminals we use to interact with the digital world. In industrial applications these are the monitors on the plant floor that allow informed, safer choices. Developers and users continue to improve HMIs and apply them in newer environments.

In dairy processing acilities, incoming milk is chilled rapidly to 4° C and distributed to various silos for different end products. Each product has different tolerance during processing, and HMIs display this to plant operators in real-time for analysis and decision making. New models of HMIs and monitoring sensors have standardized these silos with new features like alarms for high or low temperatures as well as flow meters and float switches for distribution data, batch reports, and overflow warnings. Some new features can control pumps, and agitators for each individual silo as well.

Click here for the full article on Control Global.