Types of Pressure Taps used in Orifice

Any restriction in the flow pipe causes a drop of pressure that is, the downstream pressure lowers by an amount equal to the pressure drop due to the restriction. In case of orifices, the drop in pressure varies from the location of the orifice plate to the downstream side until the flow becomes fully developed. The pressure drop is at its maximum at the vena contracta. Taps are used to sense the pressure and they are classified based on their location.

Corner Taps

In this arrangement, openings for the pressure taps are located in the upstream and downstream flanges holding the orifice plate

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Piping Corrosion and Corrosion Protection

1. Introduction

Corrosion is the degradation of a metal or alloy, as a result of chemical reaction with its environment. The degradation is caused by an oxidation reaction, In electrochemical sense, oxidation is metal atom (M) losing electrons. (Not necessarily to Oxygen).

M → M + e

By the corrosion attack of any type, component can weaken. The rate and nature of attack is influenced by mechanical stress, thermal stress, cyclic stress, temperature, type of environment, type and nature of corrosion product formed, etc. Since the parameters are at large and can vary, it is difficult to predict the corrosion behavior. The harm to the life of the component also depends on the type of corrosion attack Pitting type-localized corrosion may puncture the container earlier than a uniform corrosion. And the spalled corrosion product debris of uniform corrosion may choke the inside of heat exchanger. threatening its life.

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How to Select a Valve

Each valve assembly consists of a valve body, an actuator and a linkage kit. The instructions and tables in this catalog will guide you in selecting the proper components or factory assemblies.

1. Determine the Application Criteria

• Flow type required:

o two-way, equal % or modified linear

o three-way, mixing or diverting

• Fluid type (hot water, steam, glycol, etc.)

• Fluid temperature

• Inlet pressure required

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Various Considerations in Equipment Layout in the Equipment and Plot Plan

Learning Objectives

Equipment layout is based on certain considerations. The final plant design is executed on the this drawing and it should be seen that plant should be safe and economical. This equipment layout is very important because this is used for the execution of plant.

The piping engineer has to understand the concept of equipment layout and consideration. While preparing layout, the piping engineer should design a steady process, non-hazardous utility and facility.

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Types of Check Valves and Its Applications

A check valve, clack valve, non-return valve or one-way valve is a mechanical device, a valve, which normally allows fluid (liquid or gas) to flow through it in only one direction.

Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. Check valves are often part of common household items. Although they are available in a wide range of sizes and costs, check valves generally are very small, simple, and/or inexpensive. Check valves work automatically and most are not controlled by a person or any external control; accordingly, most do not have any valve handle or stem. The bodies (external shells) of most check valves are made of plastic or metal.

An important concept in check valves is the cracking pressure which is the minimum upstream pressure at which the valve will operate. Typically the check valve is designed for and can therefore be specified for a specific cracking pressure.

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Pigging in Pipeline Pre-commissioning

INTRODUCTION

After a pipeline is constructed and before it is put into service there are a number of key activities required in order to ensure that the pipe meets the requirements of its owners or operators. These will vary to some extent depending on the service for which the line is intended, but as a minimum they will be looking for verification that the line has been laid without significant defects and is in a condition suitable to be filled with the intended product.

Pipeline pigging has a significant role to play in meeting these conditions, and pigs are met with in a number of guises during pre-commissioning operations. This paper is intended to provide an overview of the uses of pigs in these operations, and provide some basic information on train design and pig selection. Some examples are drawn from a range of types of construction and pre-commissioning projects in order to give a feel for the practicalities of the operations described.

PIPELINE PRE-COMMISSIONING ACTIVITIES

The principal activities involved in preparing a pipeline for operation are those of filling, cleaning and gauging; hydrotesting; dewatering and drying. As in many other pipeline operations, pigs are the tool of choice in achieving many of the goals in this area. Activities that are thought of as pre-commissioning cover the entire range necessary to prepare a newly laid pipeline for handover to its operator. Following the construction phase of the pipeline build, the line may be physically complete, but will require significant
preparatory works prior to being ready for service.

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