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Type of Valves and Its Features

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Type of Valves and its Features There are three basic functions of valves are 1. To stop flow 2. To keep a constant direction of flow 3. To regulate the flow rate and pressure. To select the correct valve to accomplish these functions properly, an outline of the different types of valves and their features is given below. Butterfly Valve: Valve shaped like a butterfly.

Features of the ROTEX DRS Scotch Yoke Actuator

Actuator Modules

ROTEX actuator spring modules and pneumatic modules can be removed, swapped, rebuilt, or reinstalled on the frame module without disassembling the frame module. No need even to remove top cover of frame module, because all bolting for removal of the modules is external.
Actuators can easily be changed in the field from fail close to fail open by just swapping the positions of the spring and pneumatic modules. No need to dismantle the frame cover or cylinder assembly.
Actuators can be modified from double acting to spring return easily in the field by adding a spring module.

Springs are lifetime lubricated and epoxy coated.

Springs are pre-compressed inside their welded spring modules for safety and ease of use.
Pneumatic cylinders are lined with hard chrome plating. Smooth to eliminate wear of piston seals, the surface is very hard, for long life.
Inside the pneumatic module, dual oversized tie rods are protected from external corrosion. Where the tie rods pass through the piston head, ROTEX has improved the design by providing a slide bearing, where most designs don’t. This bearing is important to help maintain alignment and assure smooth operation.

Frame Module

Inside the frame module, the yoke is supported by life time lubricated bearings. Needle roller bearings ensure the most efficient torque transmission.
Extra heavy duty travel adjustment bolts allow for +/- 10% adjustment of the 90 degree stroke. The area of contact is large, to withstand the impact forces.
The yoke thrust pin is made of case hardened steel to resist wear.
The piston shaft is supported on each side of the frame module by solid bearings that ensure proper alignment and smooth operation.

Flexijoint

Each piston shaft of the ROTEX DRS is equipped with two Flexijoints. These specially designed joints compensate for movement and changes in alignment to reduce internal stresses and increase output torque.
The thrust transmitted through the Flexijoints ensures no side thrust on the cylinder walls and bearings.

Unique Sealing Features

Piston seal is ROTEX X design. Flexibility of the sealing material reduces friction, prevents leakage, and extends actuator life. The X shaped seal is wear compensating, and the unique shape of the seal retains the grease for longer periods. The piston is guided by a PTFE thrust bearing, which helps keep the piston centered, and seal wear to a minimum.
The tie rod seal is also of the ROTEX X design. Old fashioned O-rings are replaced by these flexible, low friction, resilient seals to reduce the failure rate of tie rod seals. Also reduces the wear and tear to the tie rods themselves.
ROTEX has also replaced the standard O-ring of the shaft seal. In this position, we provide a proven V-seal design. This self-energized, wear compensating seal guarantees low hysteresis and minimum friction. Like the X seal of the piston and tie rod seals, the inherent shape of the V-seal helps keep the grease where it needs to be.

Optional Hydraulic Override

ROTEX DRS actuators may be ordered with an optional hydraulic override, or the override may be retrofitted to an existing actuator.
The override is fitted into the spring cartridge, to keep the overall dimensions of the actuator and override to a minimum. Can withstand up to 2,000 psi hydraulic pressure.
Easy to operate.
Special Z seal ensures zero leakage and extended life.

ROTEX Pneumatic Valve Actuator Introduction

Here is a movie/slideshow introducing the ROTEX family of pneumatic valve actuators. The movie includes the ECV "Infinity line of rack and pinion actuators, the DRS scotch yoke series and the DRC and DRV large scale rack and pinion series.

Unique design and high performance features are explained and pictures of automated valve packages are included.

What is Valve Trim?

Valve Trim is collective name for the internal elements of the valve. The Valve Trims are directly exposed to the process fluid except the body, bonnet, flanges and gaskets. As per API code Trim is defined as the seating surfaces of the body, disc, disc to shaft connection hardware (e.g., keys, pins, screws, etc.) and any internal fasteners that are in contact with the process fluid.

The Plug,

Valve Actuation 101: Comparative Review of Pneumatic Actuators and Advantages of Rack and Pinion

Here's is a good presentation on the various types of industrial pneumatic valve actuators, such as scotch yoke, vane, diaphragm and rack and pinion, and their respective advantages and disadvantages.

ROTEX Controls USA: Valve Automation 101 from ROTEX Controls USA

VALVE PARTS AND TERMINOLOGY

VALVE PARTS AND TERMINOLOGY
Port: Entrance and exit opening in the body.
Body: Pressure containing portion of valve with end connections

Disc: Linear movable element with sealing surface (gate, globe, check and butterfly)

Rotor: Rotating movable element with sealing surface (ball, plug)

Body Seat: “Stationary” sealing surface inside the body that contacts the disc or rotor

Weld

Advanced Design Considerations for Best-in-Class Scotch Yoke Actuators

Evaluating the design features of a Best-in-Class scotch-yoke pneumatic actuator, for example the Rotex Controls DRS.

Actuator Modularity

Actuator spring modules and pneumatic modules should be able to removed, swapped, rebuilt, or reinstalled on the frame module without disassembling the frame module. No need even to remove top cover of frame module, because all bolting for removal of the modules is external.

Actuators should be easily changed in the field from fail close to fail open by just swapping the positions of the spring and pneumatic modules. No need to dismantle the frame cover or cylinder assembly.

Actuators should be able to be modified from double acting to spring return easily in the field by adding a spring module.

Springs

Springs should be lifetime lubricated and epoxy coated.

Springs should be pre-compressed inside their welded spring modules for safety and ease of use.
Pneumatic cylinders should be lined with hard chrome plating. Smooth to eliminate wear of piston seals, the surface is very hard, for long life.

Inside the pneumatic module, dual oversized tie rods should be protected from external corrosion. Where the tie rods pass through the piston head, design should include a slide bearing. This bearing is important to help maintain alignment and assure smooth operation.

Frame Module

Inside the frame module, the yoke should be supported by life time lubricated bearings. Needle roller bearings ensure the most efficient torque transmission.

The actuator should include extra heavy duty travel adjustment bolts allow for +/- 10% adjustment of the 90 degree stroke. The area of contact is large, to withstand the impact forces.

The yoke thrust pin should be made of case hardened steel to resist wear.

The piston shaft should be supported on each side of the frame module by solid bearings that ensures proper alignment and smooth operation.

Flexijoint

Each piston shaft should be equipped with two Flexijoints. These specially designed joints compensate for movement and changes in alignment to reduce internal stresses and increase output torque.

The thrust transmitted through the Flexijoints ensures no side thrust on the cylinder walls and bearings.

Unique Sealing Features

Piston seal should be an X design. Flexibility of the sealing material reduces friction, prevents leakage, and extends actuator life. The X shaped seal is wear compensating, and the unique shape of the seal retains the grease for longer periods. The piston should be guided by a PTFE thrust bearing, which helps keep the piston centered, and seal wear to a minimum.

The tie rod seal should also be X design. Old fashioned O-rings should be replaced by these flexible, low friction, resilient seals to reduce the failure rate of tie rod seals. Also reduces the wear and tear to the tie rods themselves.

Standard O-ring of the shaft seal should be replaces. In this position, a proven V-seal design should be provided. This self-energized, wear compensating seal guarantees low hysteresis and minimum friction. Like the X seal of the piston and tie rod seals, the inherent shape of the V-seal helps keep the grease where it needs to be.

Optional Hydraulic Override

Advanced design scotch-yoke actuators should have optional hydraulic override, or the override may be retrofitted to an existing actuator.

The override is fitted into the spring cartridge, to keep the overall dimensions of the actuator and override to a minimum. It should be able to withstand up to 2,000 psi hydraulic pressure.

Completely Interchangeable Solenoid Valve Coils and Bodies Make Life Much Easier for Your Maintenance Staff

ROTEX Solenoid Valves with
Completely Interchangeable Coils

ROTEX Controls line of industrial solenoid valves are the best choice for industrial plants today. While the life-time warranty against coil burnout would normally be enough reason (the ROTEX coil is so well designed and the quality is so strong that ROTEX stands behind them unconditionally for their lifetime) the most compelling reason to choose ROTEX solenoids for your plant is their complete coil/body interchangeability.

All ROTEX solenoid valve bodies and coils are interchangeable, allowing for more efficient and less costly inventory. But most importantly, they make it very easy for maintenance crews to quickly change out valves - no matter the area classification or valve type. Other manufacturers’ valves have to be matched, so to be safe, valve and coil are replaced - even when nothing is wrong with one component.

With ROTEX, all that’s needed is the replacement of individual part. This is a greatly appreciated feature, particularly during late night service calls or when searching through storeroom shelves looking for the right part.

Advantages of Angle Seat Valves

ROTEX Angle Seat Valve

The term “angle valve” or “angle seat valve”refers to a family of on-off and control valves that have a “Y” pattern body style, and use linear action to lift a piston off a seat to open and close the valve, while providing a very tight shutoff. By having the seat on an angle, the piston can be pulled out of the flow path, eliminating its obstruction, and therefore provide maximum flow. These valves are known for their large flow rates, they can operate with zero differential pressure and with high process media temperatures. Additionally, it’s a good choice for fluids with higher viscosities and also with dirty process media. They are an excellent choice for water and steam. Angle valves are also a good choice in hazardous areas when the accompanying pilot valve is located outside of the hazardous area.

Angle valves are piloted by air and have a service life well in to the millions of cycles. Usually a three way solenoid valve is used to operate the valve. The air pressure from the pilot valve is used in the angle valve actuator to provide linear movement to the piston. Double acting valves have no spring and depend on the supply air to determine the valve position. Spring return valves use springs in the actuator housing to return the valve to its resting state.

The top of the angle valve usually includes some type of “dome” position indicator, such as a red or yellow visual beacon.

These valves deliver millions of continuous cycles in demanding applications such as steam, water, and aggressive media. Working pressures above 500 psi and able to withstand temperatures to around 400 deg. F. The valve body materials are typically 316 stainless steel or brass, with wetted materials being 316 ss or CF3M. Process connections include NPT, ANSI flanges, socket weld, butt weld, tri-clamp (sanitary), tube ends, etc. The are available in NC/ NO/ Bi-Directional, can be easily converted from NC to NO, double acting to single acting. The actuators come with threaded/ NAMUR ports and these valves do not require lubricated pilot air. They are ideally suited for vacuum service and can be used in extremely fast acting applications up to 1000 cycles per hour with expected life of over 10 million cycles.

What are NAMUR Mount and Pipe Mounted Solenoid Valve Mounting Styles?

NAMUR Mount Solenoid

When selecting a solenoid valve for valve automation, the preferred mounting method needs to be considered. The two most common choices available are "NAMUR" mount and "PIPE" mount.

NAMUR on Actuator

NAMUR mount solenoids use a standardized "sub-plate" which months directly to the actuator on one side and to the solenoid valve on the other. This adaptor allows for quick change-out and minimizes the amount of plumbing required and is therefore less expensive to install.

Pipe Mount Solenoid

Pipe mount solenoids use the supply piping for support and mounting. Pipe mount solenoids are less compact and require more effort to service, but can be installed on any system as you are not limited to a pre-existing pattern and have more selection in valve size.

Pipe Mount on Actuator

Advanced Scotch Yoke Design Increases Service Life

ROTEX recently replaced some old "orange" scotch yoke actuators with the DRS series. The customer is a major international producer and marketer of food and agricultural products. The "orange" actuators were experiencing high wear and had to be rotated out and serviced every few months. After the ROTEX DRS actors were installed, at last count, they had 125,000 cycles without any internal corrosion or degradation.

Let's examine the design improvements that allow this superior performance:

Pneumatic cylinders are lined with hard chrome plating. Smooth to eliminate wear of piston seals, the surface is very hard, for long life.
Springs are lifetime lubricated and epoxy coated.
Inside the pneumatic module, dual oversized tie rods are protected from external corrosion. Where the tie rods pass through the piston head, ROTEX has improved the design by providing a slide bearing, where most designs don’t. This bearing is important to help maintain alignment and assure smooth operation.
Inside the frame module, the yoke is supported by life time lubricated bearings. Needle roller bearings ensure the most efficient torque transmission. The piston shaft is supported on each side of the frame module by solid bearings that ensure proper alignment and smooth operation.
Each piston shaft of the ROTEX DRS is equipped with two Flexijoints. These specially designed joints compensate for movement and changes in alignment to reduce internal stresses and increase output torque. The thrust transmitted through the Flexijoints ensures no side thrust on the cylinder walls and bearings.
Piston seal is ROTEX 3X design. Flexibility of the sealing material reduces friction, prevents leakage, and extends actuator life. The 3X shaped seal is wear compensating, and the unique shape of the seal retains the grease for longer periods. The piston is guided by a PTFE thrust bearing, which helps keep the piston centered, and seal wear to a minimum.
The tie rod seal is also of the ROTEX 3X design. Old fashioned O-rings are replaced by these flexible, low friction, resilient seals to reduce the failure rate of tie rod seals. Also reduces the wear and tear to the tie rods themselves.
ROTEX has also replaced the standard O-ring of the shaft seal. In this position, we provide a proven V-seal design. This self-energized, wear compensating seal guarantees low hysteresis and minimum friction. Like the X seal of the piston and tie rod seals, the inherent shape of the V-seal helps keep the grease where it needs to be.

In 13 months, the ROTEX DRS went 125000 cycles without internal corrosion nor significant wear.

What is a Rack & Pinion Actuator?

According to Wikipedia, "A rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. A circular gear called "the pinion" engages teeth on a linear "gear" bar called "the rack"; rotational motion applied to the pinion causes the rack to move, thereby translating the rotational motion of the pinion into the linear motion of the rack."

Image courtesy of Wikipedia

When applied as a pneumatic valve actuator, opposing racks are attached to pistons in a cylinder. When one side is pressurized, the pinion bearing turns in one direction. When air or spring tension is applied to the opposite side, the pinion bearing turns in the other direction, thus allowing rotational motion in both directions.

Transparent actuator showing opposing pistons (ROTEX)

Pinion bearing and rack with piston and seal (ROTEX)

Housing which forms outer pneumatic cylinder walls (ROTEX)

Advantages of pneumatic rack and pinion actuators are compactness and space savings, reliability, durability and life cycle. Disadvantages are gear and bearing wear, piston seal fatigue and stem seal leakage.

Here is a great article on rack and pinion actuators from Valve Magazine.

Critical Service, Triple Off-Set Metal Seated Butterfly Valves with ASME Supply Tank, Fusable Links and Manual Hydraulic Over-Ride

16" & 10 " Triple Off-set Valves automated block valves. These are pneumatically operated valves with ASME air tanks for fail close operation on loss of electrical signal. Also included are manual hydraulic over-ride cylinders and spring loaded 3-way diverter valves with "fusible links.

After installation of valve in to pipe line, plant air is supplied to the tank inlet valve. A pipe from the tank outlet to the actuator with filter and regulator provides the actuator clean, regulated supply air.

All electrical connections for limit switch and solenoid valves are terminated in the limit switch housing.

Valve are supplied with small 3-way ball valves with fire-safe "fusible" links and spring loaded handles that will close the valve in the event of a fire.

The manual hydraulic over-ride is used in case of loss of air, or loss of electric. 6 foot and 15 foot hydraulic lines are used to supply the hydraulic cylinders power and must be connected of the valves will not function.

As designed, these valves open in under 5 seconds and close in 1.6 seconds, have the ability to be manually over ridden in the event of a loss of air or electric, and have fire-safe spring loaded links to close the valve in the event of a fire.

Defining a "Quick Acting" Pneumatic Actuator

The desired speed of the pneumatic actuator opening or closing is a consideration of the application itself. For applications where an open valve may feed a fire, or overfill a tank, quick closing is required. Conversely, there are times when lines or tanks need to vented very quickly, or processes must be diverted quickly, and a fast opening actuator is applied.

Pneumatic Actuators can vary in opening and closing speed, depending on air supply, venting orifice, and/or size spring involved. A very general statement of valve actuator opening/closing times is normally in the "tens of seconds" whereas fast acting actuators open or close typically in less than 5 seconds.

The engineering of quick acting actuators must be done by seasoned professionals who fully understand the process. Other considerations when applying fast acting actuators are redundancy, failure mode (loss of energy supply), media, criticality and size.

Picture courtesy of Rencor Controls.

DOUBLE BLOCK AND BLEED BALL VALVE ANIMATION

Double Block and Ball Valve Animation How it works Double Block and Bleed Valve Double block and bleed valve, DBB valve animation, DBB How it works?

Choke Valve–General Info

Choke Valves are specially designed for Oil & Gas well head applications.

Choke Valves are used for surface & sub surface context. They are used for controlling the flow on production, reinjection and subsurface well heads. The well flow is controlled with Choke Valve. The purpose of the choke valves serve is to kill the pressure from reservoir and regulate the downstream pressure in flow lines

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