Intro4u2u

The valve disk or main seal is held open via spring force. This spring will automatically keep the valve open regardless of line pressure. Standard shop air or hydraulic power is used to compress the spring and close the valve. Valves require a 3-way air solenoid valve to control the air or hydraulic pressure used.

* 1,000,000+ cycles tested under laboratory conditions; some applications report over 2,000,000 cycles in field use. Your results may vary.
* No metal parts in wetted area.
* Rugged molded construction.
* Patented Fail-Dry® vented design.
* Resistant to atmospheric corrosion.
* PTFE bellows design eliminates the problems often encountered with highly aggressive chemicals, also eliminates the need to have

Actuated or automatic valves that revert to a pre-determined position after the actuating force is removed are referred to as “fail-safe” valves. The most common type is “fail-safe normally-closed.” On the other hand, “fail-safe normally-open” valves are much less common, but are equally important. These are often found in cooling systems, or are used where

Convert a current signal to a pneumatic signal so a DCS, PLC, or PC can control a valve or actuator; or convert pneumatic signals to current signals so remote pneumatic devices can interface with electronic instruments and computer-based monitoring systems.

Hazard and Risk Analysis
In the United States, OSHA Process Safety Management (PSM) and EPA Risk Management Program (RMP) regulations dictate that a PHA be used to identify potential hazards in the operation of a chemical process and to determine the protective measures necessary to protect workers, the community, and the environment.
The scope of a PHA

IEC 61511 requires that a functional safety assessment (FSA) be performed prior to the introduction of process materials in to the equipment under control (EUC). This requirement is similar to the pre-startup safety review (PSSR) called for by OSHA and other regulatory bodies around the world.
IEC 61511 requires that at least one senior, competent, independent

The safety requirement specification (SRS) is a documentation requirement of IEC 61511 and ANSI/ISA S84.01-2003 and is an integral part of the Safety Lifecycle model.
The SRS is a summary of key decisions that must be made prior to the conceptual design. The purpose of the SRS is to define the envelope of the Safety Instrumented

SIL & TUV AK Approvals
Safety Integrity Levels (SIL) pertain to the degree of process hazard and the required system reliability. TUV is a certification for individual components for use in certain SIL system applications. For more detail, search for an article by Dave Harrold, CONTROL ENGINEERING regarding CERTIFICATION. ANSI/ISA S84.01 and IEC 61508 address safety system

This presentation and hand-outs are intended for process engineers, operational personnel and others that are involved in the process of IPF Classification and testing. It is made for those who need to know the basics and essentials of IPF classification without having to know all details, if’s and but’s. This presentation aims to provide appreciation of the IPF method

All components used in SIL1, 2 and 3 functions shall be independent of components used for monitoring and control with the following exceptions:
For a SIL1 function the final element may be a control valve if the demand of the IPF cannot be caused by a malfunction of the valve and the valve is not leakage

Industry is moving towards the use of high integrity protection systems (HIPS) to reduce flare loading and alleviate the need to upgrade existing flare systems when expanding facilities. The use of HIPS can minimize capital project costs, while meeting an evolving array of standards and regulations. This paper will discuss API and ASME standards and

ANSI/ISA-S84.01-1996 and IEC 61508 require the establishment of a safety integrity level for any safety instrumented system or safety related system used to mitigate risk. Each stage of design, operation, maintenance, and testing is judged against this safety integrity level. Quantitative techniques can be used to verify whether the safety integrity level is met. ISA-dTR84.0.02

FIRE AND GAS  DETECTION SYSTEM
MULTIPLAN R&F and Associates determine carefully the numbers and locations of detectors.
MULTIPLAN R&F  and Associates use NFPA72 and other standards and the vendors recommendation for the design of fire & gas system and layout and definition of fire zones.
Fire and gas detection systems is a part of the control and safety

Consistency is the hallmark of any great organization or process. When it comes to fire and gas systems (FGSs), consistency is not a desired goal; it is a must. But since the promulgation of ISA S84.01 in 1996, there has been confusion surrounding the treatment of fire and gas systems. Some believe that the standard

Typically, the Emergency Shut Down control system consists of:Air/hydraulic power unit
Pneumatic logic module
Remote push-button stations
ESD reset station

System design is based on a ‘fail-safe’ philosophy’ and makes use of rig-air as the primary power source.  The Control System operates in conjunction with ESD valves.

A fast shutdown system and a process for the fast shutdown of a nuclear reactor, include a reactor core and a plurality of control rods which are disposed side by side and can be inserted into and withdrawn from the reactor core. The plurality of control rods has a number of operating groups into which

The present invention relates generally to a system for automatically shutting down cooking appliances and/or associated equipment in accordance with NFDA recommended standards in the event of a fire, and in particular to a fail-safe system of this type that will also shut down in the event of a failure in the system, and which

WHAT IS THE SIS?
ISA 84 uses the term “safety instrumented system” to refer to both an instrumented loop used to mitigate process risk related to catastrophic incidents and a collection of instrumented loops in a PLC.
This has led many people to believe that the PLC constitutes the safety instrumented system. IEC

The operation of many industrial processes involves inherent risk. Instrumented Protection Systems are specifically designed to reduce the severity of the impact of an emergency event. These systems, such as Safety Instrumented Systems and others, are designed to monitor a process for potentially dangerous conditions. During an emergency event, the SIS activates the valve to

6. Response time (speed) requirements for the SIF to bring the process to a safe state. This includes detection time, decision time, final element action time, transmissions times, and time to bring the system to a safe or mitigated state. 7. The safety integrity level (SIL) and mode of operation (demand/continuous) for the SIF.

Instrumented protective functions (IPFs) are commonplace in the oil and gas industry, known variously as process safeguarding, emergency shutdown (ESD), process shutdown (PSD), etc. Here, we are looking at individual functions rather than the whole system:  an example of an IPF is “high pressure in the first stage separator detected by pressure switch PSH-101 closes [

The term “safety instrumented function” or SIF is becoming common in the world of safety instrumented systems (SISs). It is one of the increasing number of S-words–SIS, SIL, SRS, SLC, etc.–that are coming into our safety system terminology. The definition of a SIF as provided in IEC standard 61511, “Functional safety: Safety Instrumented Systems for the

Maintenance Tips
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Solenoid valves are devices that use a solenoid to control valve activation. Actuation methods include electric, electro-hydraulic, electro pneumatic, and pneumatic. Unpowered states include normally open and normally closed. In a tandem center solenoid valve, the pressure and tank ports are connected while the service ports are blanked. This allows system unloading while still providing

Emergency shut-off valves (ESV) automatically close in the event of an emergency to prevent the loss of handled media. Emergency shut-off valves (ESV) are installed on fuel lines, steam and hot water pipes, vapor lines, and hoses carrying caustic or hazardous liquids and gases. Emergency shut-off valves (ESV) are frequently installed on residential water and gas

Control valves or proportional valves are power-operated devices used to modify fluid flow or pressure rate in a process system. These valves are used throughout industry in many applications.  Control valves types include globe, diaphragm, pinch, knife or gate, needle, butterfly, ball, and plug.  Globe valves are linear motion valves with rounded bodies, from which

Manual valve actuators do not require an outside power source to move a valve to a desired position. Instead, they use a handwheel, chainwheel, lever, or declutchable mechanism to drive a series of gears whose ratio results in a higher output torque compared to the input (manual) torque. Most manual valve actuators use worm gears,

Hydraulic linear actuators use a cylinder and hydraulic fluid for motive force. Like other hydraulic systems, the force applied at one point is transmitted to another point using an incompressible fluid. A hydraulic linear actuator requires relatively little maintenance and can operate for prolonged periods of time under adverse environmental conditions. Consequently, hydraulic linear actuators

Valve actuators mount on valves and, in response to a signal, move a valve to a desired position using an outside power source. There are several basic types of valve actuators: manual, electric, pneumatic, and hydraulic. Manual valve actuators do not require an outside power source. They use a handwheel or lever to drive a

Electrohydraulic valve actuators and hydraulic valve actuators convert fluid pressure into motion in response to a signal. They use an outside power source and receive signals that are measured in amperes, volts, or pressure. Some electrohydraulic valve actuators and hydraulic valve actuators move rotary motion valves such as ball, plug, and butterfly valves through a

Health monitoring leaves fewer reasons to live with stiction, wrong-sizing and excessive wear. The routine of monitoring and prioritizing maintenance targets is becoming increasingly automated and criteria-driven. Technicians needn’t assess each valve’s current operating condition. Rather, control systems using open communications standards allow individual valves to monitor their own health and call home for help when

The terms “direct” and “reverse” are frequently used when discussing control valves, positioners, and controllers. While the definitions of direct and reverse seem pretty straightforward, they cause quite a bit of confusion - especially when split-ranging is done. The key to working with control valves and controllers is to remember that there must always be a

1. If you are dealing with a corrosive fluid, choose the valve body and trim material to match the pump casing and impeller.
2. Velocity is the key to handling abrasive materials. Normal city water velocity is about 7 to 10 F.P.S. (clean liquid). If you have a fluid that is abrasive, keep the velocity as

Trim design will affect how the valve capacity changes as the valve moves through its complete travel. Because of the variation in trim design, many valves are not linear in nature. THE RELATIONSHIP BETWEEN VALVE CAPACITY AND VALVE TRAVEL IS KNOWN AS THE FLOW CHARACTERISTIC OF THE VALVE. Valve trims are specially designed, or characterized,

Being the Final Control Element in a system is not an easy job. To start with, you are blamed for any and all problems that crop up in the process. You are subjected to corrosion, high velocity, cavitation, flashing liquids, cryogenic temperatures, high temperatures, abrasion, and thermal shock. You are expected not only to throttle

Spring and Diaphragm Lowest Cost Limited Output Capability Can Throttle Without a Positioner Large Size and Weight Simplicity   Inherent Fail-Safe Action  Low Supply Pressure RequiredAdjustabilityEasily Maintained Pneumatic Piston High Torque CapabilityFail-Safe Requires Accessories or Addition of SpringCompactPositioner Required for ThrottlingLightweightHigher Cost Adaptable to High Ambient Temperature High Supply Pressure Required Fast Stroking Speed  Relatively High Actuator Stiffness Electric Motor Compactness igh CostVery High Stiffness Lack of Fail-Safe Action High Output Capability Limited Duty Cycle Slow

valves
Control valves and instruments constitute the beating heart of your plant. Malfunctions of this equipment have immediate consequences for the quality of your finished product, and for this reason the equipment must be maintained in perfect condition. GTI has many years experience in the overhaul of industrial pneumatic and electronic control valves and instruments. GTI

Burner does not igniteCauseSolutionNo gas flowThermostat set too lowTrash in main burner officeTrash in gas linesCheck with

To maximize the utility of diagnostic equipment used in chemical processing, technicians must stretch their knowledge of control valves and related diagnostic equipment that keeps tabs on valve health and safety. Too often, maintenance data isn’t used as effectively as it could be, and institutionalized half-measures result in lost money, time, safety and efficiency. To

Introduction
Fundamentals, Manual Valves, Check Valves, Pressure Relief Valves, Rupture Discs, Units of measurements, Identification of Valve Size and Pressure Class Standards
FundamentalsFluid Tightness of ValvesValve Seals, Leakage Criterion, Proving Fluid TightnessSealing MechanismSeal ability Against Liquids,  Scalability Against Gases, Mechanism for Closing Leakage Passages,Valve Seatings,Metal Seatings, Sealing with Sealants, Soft Seatings,Gaskets,Flat Metallic Gaskets, Compressed Asbestos Fiber Gaskets,

First, you have to realize that you are mixing different concepts. Temperature is a fundamental — basically defined by saying there is no net energy transfer between two things if they are at the same temperature. Then there are concepts of energy.  One can start with the internal energy which in some sense measures how much energy the fluid

All valves, except for reduced-opening valves, shall be furnished in the nominal sizes (DN) listed in Tables 2 to 6. Reduced-opening valves shall be furnished in the nominal sizes in accordance with Table 1.
NOTE In this International Standard, DN sizes are stated first followed by the equivalent NPS size between brackets. Except for reduced-opening valves, valve sizes

Gaskets Compressed asbestos fiber is designed to combine the properties of rubber and asbestos. Rubber has the ability to follow readily the surface irregularities of the flange face, but it cannot support high loads in plain strain or withstand higher temperatures. To increase the load-carrying capacity and temperature resistance of rubber, but still retain some

In the case of soft seatings, one or both seating faces may consist of a soft material such as plastic or rubber. Because these materials conform readily to the mating face, soft seated valves can achieve an extremely high degree of fluid tightness. Also, the high degree of fluid tightness can be achieved repeatedly. On

The leakage passages between metal seatings can be closed by sealants injected into the space between the seatings after the valve has been closed. One metal-seated valve that relies completely on this sealing method is the lubricated plug valve. The injection of a sealant to the seatings is used also in some other types of

Valve seatings are the portions of the seat and closure member that contact each other for closure. Because the seatings are subject to wear during the making of the seal, the scalability of the seatings tends to
diminish with operation Metal Seatings Metal seatings are prone to deformation by trapped fluids and wear particles. They are further damaged by corrosion, erosion,

Sealability Against Liquids The scalability against liquids is determined by the surface tension and the viscosity of the liquid. When the leakage capillary is filled with gas, surface tension can either draw the liquid into the capillary or repel the liquid, depending on the angle of contact formed by the liquid with the capillary wall.

Valve Seals One of the duties of most valves is to provide a fluid seal between the seat and the closure member. If the closure member is moved by a stem that penetrates into the pressure system from the outside, another fluid seal must be provided around the stem. Seals must also be provided between

Valves are the components in a fluid flow or pressure system that regulate either the flow or the pressure of the fluid. This duty may involve stopping and starting flow, controlling flow rate, diverting flow, preventing back flow, controlling pressure, or relieving pressure. These duties are performed by adjusting the position of the closure member

Cavitation Cavitation shall be generally understood as the dynamic process of the formation and implosion of cavities in fluids.Cavitation occurs, for instance, when high flow velocities cause the local hydrostatic pressure to drop to a critical value which roughly corresponds to the vapor pressure of the fluid. This causes small bubbles filled with steam and [

Cavitation has been a familiar phenomenon for a long time particularly in shipping. In 1917, the British physicist Lord Rayleigh was asked to investigate what caused fast-rotating ship propellers to erode so quickly. He discovered that the effect of cavitation, already proved in experiments by Reynolds in 1894, was the source of the problem. Despite

One of the fastest changing areas of the control loop is the final element, which is usually a valve. Typically, all of the emphasis and engineering focus are on the point of measurement and the control system, but little has been said about the final control element, which for this article is a valve. Additionally,

Joule-Thomson Effect A phenomenon called the Joule- Thompson effect occurs in gas mixtures whenever pressure is reduced. This effect is the result of the forces of attraction between molecules being greater at high pressure than low. The molecules slow down as they pass through a restriction such as a pressure regulator. After a pressure drop

General Information on Elastomer Materials
BUNA “N”
Buna “N” is commonly referred to as a nitrile rubber, and is ASCO’s standard synthetic elastomer for accomplishing resilient-type seating or sealing. It has excellent compatibility for most air, water and light oil applications. It has a useful temperature range of 0F. ( - 18°C.) to 180°E (82°C.).

Gas valves are used to handle and control the flow of gaseous media such as liquefied petroleum and natural gas. They are made of metal or plastic and vary in terms of valve size, pressure rating, number of ports, and flow.

The Schrader Valve is a valve stem invented by August Schrader and is used on virtually all automobile tires and lower pressure bicycle tires. It is a poppet valve assisted by a spring. Schrader valves are also used on the fuel […]

Diaphragm valves (or membrane valves) consists of a valve body with two or more ports, a diaphragm, and a “saddle” or seat upon which the diaphragm closes the valve. The valve body is commonly constructed from high grades of

Surfacing for Wear Resistance. For the successful hard surfacing or overlaying operation a welding procedure should be established. The procedure should be related to the particular part being surfaced and the composition or analysis of [