Wednesday, December 11, 2013

AWWA Valve and Actuator Standards

The American Water Works Association (AWWA) the largest nonprofit, scientific and educational association dedicated to managing and treating water. Among others, AWWA members include water utilities, treatment plant operators and managers and manufacturers. The AWWA maintains and regulates the standards for design and performance of valves and actuators used in municipal water treatment and water distribution systems.

The following are the standards with links for more information:

Sunday, December 1, 2013

Control Valve Series Provide Food and Pharmaceutical Companies Better Quality and Safety

Samson Controls is offering its 3249 valves that eliminate nooks and crannies in the valve body and seat area to decrease the potential for contaminants and bacterial growth.

The valve comes with EPDM (ethylene propylene diene monomer rubber) and a back-up safety packing box that ensures full protection from bacteria spreading and prevents leakage.

Tuesday, November 19, 2013

Refurbish Your Coker Valves: An Economical Alternative

Coker Valve Restoration
10" Coker Valve before restoration
According to Wikipedia "A coker or coker unit is an oil refinery processing unit that converts the residual oil from the vacuum distillation column or the atmospheric distillation column into low molecular weight hydrocarbon gases, naphtha, light and heavy gas oils, and petroleum coke. The process thermally cracks the long chain hydrocarbon molecules in the residual oil feed into shorter chain molecules leaving behind the excess carbon in the form of petroleum coke."

Wednesday, November 13, 2013

Reliable Electric Actuators for Industrial Applications from RENCOR

electric valve actuator
Electric Actuators from RENCOR
RENCOR offers the ProMation Engineering Quarter-Turn Electric, Non-Spring Return Actuators featuring rugged, industrial grade design for use with all ball and butterfly valves. They offer torque outputs from 800 in lbs. to 40,500 in lbs.

The ProMation Engineering actuators feature a self-locking hardened steel drive train for smooth operation, mechanical end of travel stops, and patented clutch-free manual override for single-handed positioning of the actuator in any situation.

Some models include an integrated position indicator, two auxiliary switches, an internal low-power anti-condensation heater, and cast aluminum polymer coated housing. Using two 3/4" conduit connections, the actuators are rated NEMA 4X for safe exposure to high pressure hosing and corrosion resistance.

Proportional control units accept a wide range of control signals while generating multiple feedback signals and are easily installed, calibrated, and adjusted in the field.

The actuators are available for 24 VAC/VDC, 120/230 VAC or single phase and complete 3-Phase offerings. They are ISO 5211 compliant, conform to AWWA C540 standards, are certified to CSA 22.2 standards including ANSI/UL 50 and ANSI/UL 429, and are ARRA compliant.

Available options include torque switches, motor control centers, phase monitors, potentiometers, cold weather kits (for operation to -40 degrees F/C), timers, speed controls, single wire control interfaces, a wide array of feedback control interfaces, local control units, and fail safe solutions. All options are factory installed, calibrated, and tested.

Thursday, October 31, 2013

Baby Food Giant Turns to RENCOR for Tough Valve

steam control valve
The second largest baby food producer in the US needed a tough control valve to cook baby food. The valve was to be installed in a clean area where it would be washed with high-pressure hot water and harsh detergents several times a day.

The application was to accurately control steam so that precise temperature control could be maintained to properly cook the baby food. Accuracy is critical because of food safety and product quality.

RENCOR chose a Samson all 316 stainless steel globe control valve, with 316 stainless steel actuator and 316 stainless steel positioner as the solution. Samson control valves are known for their accurate steam control, are available in all-stainless construction, and are well suited for these types of applications.

RENCOR delivered the valve and all components just two weeks after receipt of order.

Thursday, October 24, 2013

Defining Cavitation in Control Valves

cavitation in control valves
Formation of cavitation
Cavitation is the formation of vapor spaces (bubbles) in the control valve cavity resulting from a rapid change in pressure. When the bubbles move downstream and are exposed to a larger cross-sectional area, velocity decreases and pressure increases. The surrounding higher pressure causes the lower pressure bubble to implode which causes shockwaves. These shockwaves can cause metal fatigue and cause excessive wear on the internals of the valve. As the bubbles collapse, they make a discernible sound with accompanying vibration and the damage to a valve can happen quickly (weeks or months).

Cavitation is very destructive and may wear out the trim and body parts of the valve in short time. Using hard internal materials provide a little improvement, but the harder materials also cost more and their use must be justified.

How can you minimize cavitation in control valves? You can change the process conditions and reduce operating temperatures. This may lower the vapor pressure enough to stop cavitation. Reducing the differential pressure across the valve can relieve or lower cavitation. Locating a control valve in the lowest elevation of the piping system and keeping the control valve as close as possible to the pump are  also recommended practices.

Here is an excellent and thorough technical paper on cavitation in control valves courtesy of Samson Controls.

Thursday, October 17, 2013

Superior Design Check Valve Better Than Swing Check

Proquip Check Valve Design
Many engineers apply swing check valves because they are inexpensive and their use is pretty wide spread. Our experience tells us there are better alternatives. Here are the reasons RENCOR favors Velan-Proquip valves over conventional swing check valves.

Reduced Size – Weight – Cost: 

The inherent design of the double flapper check valves results in a significantly reduced weight as compared to the conventional full bodied check valve. As the valves increase in size the Velan-Proquip valve will be as little as one fifth the weight of the full bodied unit. This results in savings in initial cost, space, and pipe support element installation.

Tuesday, October 8, 2013

What Does "Prepared for Oxygen Service" Mean for Valves?

oxygen service for valves
Image courtesy of Wikipedia
Oxygen service preparation refers to a special cleaning process that removes all traces of oils from a valve to allow use in with oxygen (O2).  Oxygen is odorless and colorless, and exists in air at approximately 21% concentration. It is non-flammable, but supports vigorous combustion to any materials that are combustible. Allowing oils or greases to contact higher concentrations of oxygen can cause ignition and even explosive outcomes. Aside from the reactive concerns, O2 preparation is also used for applications where purity is needed.

Oxygen is used extensively in medical, deep-sea, metal cutting, welding, and metal hardening. The steel industry uses oxygen to increase capacity and efficiency in furnaces. A major use is in production of gasoline, methanol and ammonia where it is used as a synthesis gas.

Friday, October 4, 2013

What is a Butterfly Valve?

high performance butterfly valve
RENCOR actuated HPBV
A butterfly valve is used for stopping or controlling flow of liquids or materials through pipes. The "butterfly" refers to the round, flat disk that allows for flow through the valve. Butterfly valves are a member of the "quarter-turn" valve family, meaning fully open to fully closed in 90 degrees rotation. They are opened and closed via a lever, manual gear operator, pneumatic actuator, or electric actuator. Butterfly valves can be used for on-off service and some varieties are used as control valves. Butterfly valves are generally less expensive than other high flow valves, lighter in weight, and take up less piping length. Since the disk is always in the flow path, butterfly valves always have a pressure drop across the valve.

Tuesday, October 1, 2013

Fail-Freeze Ball Valve with Manual Override

fail freeze ball valve and positionerThis means that, on loss of signal, the valve positioning unit will freeze the valve in the last known position based upon the pneumatic signal at the time of failure. Normally, on losing the signal air, the valve would open or close fully depending on the pneumatic positioner's setting.

However, in some situations, it's important to keep the process running at some level until the batch or system can be shutdown and checked out. This is where fail-freeze comes in handy.

RENCOR recently designed and built an automated 2" ball valve package with a fail-freeze pneumatic positioner, regulator, and pilot valve combination that assured the valve would stay put when the 3-15 psi signal air was lost.

A manual override was included that allowed for manual control of the valve during the batch process and for a controlled shut down after the batch was complete.

Friday, September 27, 2013

Outstanding Service Years After the Sale

Valve before removal
In 1987, RENCOR Controls supplied one of the largest names in paper and packaging products (a pulp & paper plant) a 6" Samson model 3251 globe valve for a power boiler feedwater application.  Boiler feedwater is a critical service. Valve failure can potentially shut down the boiler in the paper mills' power generation facility.

After the initial sale, and since 1987, RENCOR has provided onsite, yearly routine maintenance on the valve. The valve continued in service, without problem, through September 2013.

Wednesday, September 25, 2013

General Intro to Ball Valves

Ball Valves
Variety of ball valve types
Ball valves are grouped by how the valve body is made/assembled. The groups are uni-body, 3-piece, split-body, top-entry, and welded body.

Ball valves are further defined by the machined hole in the ball, called the port.

A full port valve has a port the same size as the pipeline resulting in better flow characteristics. Flow coefficients are much better, but at a higher price. There are many cases where a reduction in diameter, or the resulting change in flow is detrimental.

Thursday, September 19, 2013

Solving a Problem on High Temperature Gas Service

Gas applications many times are thought to be pretty easy applications as long as you get the seat material and wetted part compatibility correct. However, in some cases, these gases can be delivered at very high temperatures, which causes headaches when applying the proper valve.

RENCOR was approached by a customer in China who needed a high cycle, high temperature, fast operating valve. The process gas was 700 deg. F and the process pressure was 272 PSIG.  The customer also required the valve to operate in 0.5 seconds. The biggest challenge was not the temperature itself, but the lack of lubricity. The high temperature gas was very, very dry. All the metal seated ball valves they were testing ended up either galling, or were operating too slowly.

RENCOR teamed up with Velan Valve who engineered a metal seated ball valve rated for 700 deg. F at 272 PSIG. RENCOR designed a custom actuation package that delivered a high volume of high pressure supply air to a rack and pinion actuator that sped operation up to a very fast 30 milliseconds. Problem solved.

Tuesday, September 17, 2013

Samson Controls Introduces Helpful "How-to" Videos

Samson Controls, a leading manufacturer of control valves and regulators in the chemical, petrochemical, pulp and paper, power and HVAC industries is introducing a great page of "how-to" videos.

You can see them at the RENCOR Controls site here. You can also see them on the Samson Controls site here. These videos are intended to answer the most common maintenance questions and new videos will be added regularly.

Thursday, September 12, 2013

RENCOR Uses Innovation and Eye for Design to Reduces Plant Spare Parts Costs

standardized valve brackets
An age old problem at many plants are the countless types of valve and actuator brackets. Many are unique, few are standard. The need for on-hand replacements constantly puts pressure on plant inventories.

Tuesday, September 10, 2013

Paper Mill Saves Big from RENCOR'S Engineering Skills

It was once said that "a paper mill uses everything it produces except the shade the building casts". In this highly competitive business, efficiency and cost-savings go directly to the bottom line.

A well-known New England paper mill had a critical process that required two very large (24") triple offset, metal seated butterfly valves to precisely control flow manually with a gear operator. On top of that, the valves had to be zero-leakage when in the off position. Even with the best known gear operators installed, it was still difficult for the paper mill to get the control they needed.


Thursday, September 5, 2013

Small Process, Big Problem: Sometimes the Solutions are Pretty Simple

Spring return handle ball valve
Spring return ball valve
Problem: Leaks, puddles and spills under the manual valve use for sampling solvents.

Scenario: Customer routinely draws samples of solvent for testing using manual ball valves. Manual valves are not closed tightly by operator, causing small leaks and minor spills. Leaks are not at first noticeable, but drips slowly over time leading to a potentially hazardous situation. Ultimately, its an operator error situation. The fix needs to remove the human from the process.

Tuesday, September 3, 2013

An Alternative to Safety Relief Valves - Safety Trip Stop Valve

Figure 1
The Safety Trip Stop Valve shown in figure 1 is an example of the automated valves supplied by RENCOR Controls as an alternative to Safety Relief Valves as allowed by the Power Piping Code 1987Adenda to the 1986 issue. B31.1 paragraph 122.14.12.

The Power Piping Code allows for the use of this Safety Stop Valve as an alternative to Safety Relief Valves in applications where their use is difficult or impractical. Paragraph 122.14.12 from the Power Piping Code B31.1 reads as follows:

Thursday, August 29, 2013

Lime Silo Bottom Outlet Screw Feeder Isolation

Paper Mill Lime Silo Valve
Paper Mill Lime Silo Valve
Customer: Paper Manufacturer
Service: Lime Silo Bottom Outlet Screw Feeder Isolation
Process: Lime Powder at 1800 F.

Lime Silo Outlet Valve. Existing valve was a 14” RoValve through port knife gate with a Rotork electric actuator. Valve gate had galled badly and actuator could not stroke the valve with out the help of a sledge hammer driving the gate as well.

Sunday, August 25, 2013

Chlorine Ball Valves

Chlorine Ball Valve

Chlorine is hazardous and toxic. In its gaseous state it is nonflammable, greenish-yellow, and has a very distinctive odor. If inhaled it is a severe irritant. Chlorine is nonflammable, but can support combustion of certain substances. Chlorine is used in manufacturing chemicals including solvents, pesticides and herbicides, plastics, refrigerants and propellants. It is a main ingredient in bleach, deodorizer and disinfectant. Chlorine is widely used in  the pulp and paper industry as well as water and waste-water.