Bài Viết

Differential Pressure Level Detectors

Differential Pressure Level Detectors

Basic, Instrumentations 23 Tháng Sáu, 2014 at 5:13 chiều

The differential pressure (ΔP) detector method of liquid level measurement uses a ΔP detector connected to the bottom of the tank being monitored. The higher pressure, caused by the fluid in the tank, is compared to a lower reference pressure (usually atmospheric). This comparison takes place in the ΔP detector. Figure 9 illustrates a typical differential pressure detector attached toRead More

Float Level Detector

Float Level Detector

Basic, Instrumentations 23 Tháng Sáu, 2014 at 5:08 chiều

Ball Float The ball float method is a direct reading liquid level mechanism. The most practical design for the float is a hollow metal ball or sphere. However, there are no restrictions to the size, shape, or material used. The design consists of a ball float attached to a rod, which in turn is connected to a rotating shaft whichRead More

Gauge Glass Level Detector

Gauge Glass Level Detector

Basic, Instrumentations 23 Tháng Sáu, 2014 at 5:01 chiều

Gauge Glass A very simple means by which liquid level is measured in a vessel is by the gauge glass method (Figure 1). In the gauge glass method, a transparent tube is attached to the bottom and top (top connection not needed in a tank open to atmosphere) of the tank that is monitored. The height of the liquid inRead More

Thermocouple

Thermocouple

Basic, Instrumentations 23 Tháng Sáu, 2014 at 4:56 chiều

Thermocouple Construction A thermocouple is constructed of two dissimilar metal wires joined at one end. When one end of each wire is connected to a measuring instrument, the thermocouple becomes a sensitive and highly accurate measuring device. Thermocouples may be constructed of several different combinations of materials. The performance of a thermocouple material is generally determined by using that materialRead More

Resistance Temperature Detector – RTD

Resistance Temperature Detector – RTD

Basic, Instrumentations 23 Tháng Sáu, 2014 at 4:48 chiều

Temperature The hotness or coldness of a piece of plastic, wood, metal, or other material depends upon the molecular activity of the material. Kinetic energy is a measure of the activity of the atoms which make up the molecules of any material. Therefore, temperature is a measure of the kinetic energy of the material in question. Whether you want toRead More

pH Measurement

pH Measurement

Basic, Instrumentations 18 Tháng Sáu, 2014 at 4:51 chiều

pH measurement has a wide variety of industrial applications in virtually every industry. These range from water conditioning to specific process related measurements to waste treatment. Bài viết này sẽ giới thiệu sơ lược về phương pháp điện hóa là phương pháp sử dụng công cụ mà chuyển đổi đại lượng pH (độ hoạt động của ion H+) thành tínRead More

Boiler Steam and Water Flow General Description

Boiler Steam and Water Flow General Description

Hơi - Nước, Nhà máy Nhiệt điện 13 Tháng Sáu, 2014 at 1:30 chiều

Feedwater enters the bottom header of the economizer (Fig. 2). The water passes upward through the economizer and stringer tubes, and discharges through the outlet headers into piping which conducts the heated feedwater to the steam drum. The economizer stringers support the primary superheater as well as transport water to top of the boiler. The heated (but still subcooled) feedwaterRead More

Boiler Gas & Air Flow General Description

Boiler Gas & Air Flow General Description

Nhà máy Nhiệt điện, Nhiên liệu -Khói - Gió 13 Tháng Sáu, 2014 at 1:27 chiều

1. FUEL FLOW Raw coal is discharged to the pulverizers where the primary air is introduced and the fuel is pulverized. The pulverized coal is transported from the pulverizer by the primary air to the burners through a system of pressurized coal-fired piping. Each pulverizer will supply coal to burners. 2. AIR AND GAS FLOW Air from the forced draftRead More

What does PLC consist of?

What does PLC consist of?

Controls, PLC 13 Tháng Sáu, 2014 at 12:57 chiều

A typical PLC can be divided into parts, as illustrated in Figure 8 which are Central Processing Unit (CPU) Input/output (I/O) Power Supply Programming Device We shall briefly discuss each part here. Central Processing Unit (CPU) The processor (CPU) is the “brain” of the PLC. A typical processor usually consists of a microprocessor for implementing the logic and controlling theRead More

Why Use PLC?

Why Use PLC?

Controls, PLC 13 Tháng Sáu, 2014 at 12:49 chiều

The softwiring advantage provided by programmable controllers is tremendous (Figure 5 shows a practical industrial example). In fact, it is one of the most important features of PLCs. Softwiring makes changes in the control system easy and cheap. If you want a device in a PLC system to behave differently or to control a different process element, all you haveRead More