Bagaimana bekerja online

koreksi pada kesalahan kerja actuator dalam hal ini sebuah valve dalam keadaan on line memerlukan kecepatan dn kecepatan penanganan kesalahan.Hal yang perlu dilakukan dan tidak boleh terlewat oleh seorang teknisi diantaranya :

1. Identifikasi kesalahan, Cermat mengetahui penyebab error valve baik melalui pengalaman ,history alat,penglihatan dan teori manual repair guide
2. Identifikasi alat, Cermat membaca tag yang tertera di valve atau di manual book
3. Membawa repair tool , Bawa repair tool yang tepat dengan ukuran part yang akan dikoreksi
4. Pemberitahuan perbaikan, Beritahukan pada suverpisor setempat akan adanya perbaikan
5. Safety, Pakai alat keselamatan kerja sesuai aturan
6. Menentukan Langkah action pertama , Tentukan dengan benar langakah demi langkah sesuai manual book atau pengetahuan tentang kesalahan yang sesuai dengan kesalahan
7. Check hasil kerja, Tunggu beberapa saat hasil kerja anda dengan memperhatikan proses kerja alat.
8. Pemberitahuan akhir, Beritahukan kepada suverpisor setempat bahwa pekerjaan sudah selesai.
9. Menulis laporan. Tuliskan laporan dengan jelas ,singkat dan benar

Langkah tersebut perlu dilakukan untuk menyempurnakan perlakuan yang baik dan benar seorang teknisi tehadap alat dan proses secara online.Banyak teknisi melewatkan beberapa hal menyebabkan alat tersebut kembali terulang atau kesalahan tidak terkoreksi secara sempurna. Bekerja terburu buru banyak mengahasilkan kesalahan baru atau kebingungan selanjutnya. Bekerja tanpa langkah yang jelas banyak memperlambat kerja dan menghasilkan kesalahan baru. Bekerja tanpa pengetahuan akan menyebabkan kesalahn berlanjut dan tidak teridentifikasi.

Level measurement by Dp transmitter

Level measurement using DP transmitter is common to use, even can be called as a first choise for the level transmitter, but much cheaper than type2 as displacer level transmitter, radar wave, etc., in addition to easier installation.

DP Transmitter principle itself is hydostatik pressure from the formula:
P = pgh

To open the tank, for the high P diconnectkan to the bottom of the tank, while for P is low, just enough atm, this is because:
Phigh = pgh + atm, Plow = atm
So to compensate for atm, DP = pgh + atm-atm
Obtained h.

Meanwhile, close to the tank, just like an open tank, but for low P diconnectkan to the top of the tank, this is to compensate for the gas pressure from the tank:
thus becomes DP = pgh + PGAS-PGAS, so get h.

At the measurement level using DP, we must know the property (P or can also SG) is fluid.

Closed tank to have two kinds of installations are:
1. Dry Leg: where to P low, the transmitter direct contact with the fluid, in this case the fluid is a gas
2. Wet Leg: where to P low, the transmitter given the different media such as fluid (glycol / silicone oil / water-common) for compensation from the condensation of the fluid media measured (using diapragm) or because a particular case (such as a corrosive gas fluid)

Basic of calibration

To find a measure of best quality and quantity, process control is required. The value must be obtained from the gauge mounted on the process. Instrument must be accurate. Measure requires some setting of variables such as: range, zero, span, variable settings are needed to detect, manage and control the error, linearity, accuracy.
1. Process Variables
Process variable is the amount of physical or chemical quantities because of the influence of the process. Pressure, temperature, flow and level is the physical variables, whereas the oxygen content and pH values are chemical variables.
2. Range
Range is the boundary between the lowest value to highest value. For example, a physical variable of a process of value between 3 to 10 bars then, instruments used must have the highest value and the ability to measure the indicator value above 10 bar and the lowest value of 3 bars
3. Zero
Zero shows the lowest signal from the input or output and does not interpret the value of 0 (nil). A transmitter with the input range = 0 to 10 bar, output = 4 to 20 ma. So 4ma output value and input value is 0 bar zero value.
4. "Span"
The difference between the lowest and highest value is called "span", 0 to 10 bar has a value of span = 10 bar. 4 to 20mA has a span value = 16.
5. Error
The difference with the actual process value indication value measure is the actual process error.Ketika value and 5 bar gauge shows the mean error 5.2bar = 0.2bar
6. Linearity
In full-scale output than the input point as a point of readability measurement Linearity
input and output 0% 0%
input and output 25% 25%
input and output 50% 50%
input and output 75% 85%
input and output 100% 100% then the instrument is said to be non-linear
7. Accuracy
Measurement error value of the real value of the scala a full percentage accuracy values describing a tool ukur.contoh 1%, 2% is usually written on the gauge

Analog Pressure Gauges

There are several common types of mechanical analog pressure gauges including bellows, Bourdon tubes, capsule elements and diaphragm element gauges. Analog pressure gauges should be selected considering the media and ambient operating conditions. Gauge selection should take into consideration the corrosive environment in which it is to operate. The media being measured must be compatible with the wetted parts of the pressure instrument. Improper application can damage the analog pressure gauge, causing failure or personal injury and property damage. Diaphragm seals (also called gauge isolators) can be added to the system to protect the gauge from corrosive attack, and prevent viscous or dirty media from clogging Bourdon tube analog pressure gauges.

Bourdon tubes are circular shaped tubes with an oval cross-section. The pressure of the media acts on the inside of this tube resulting in the oval cross-section becoming almost round. Because of the curvature of the tube ring, the Bourdon tube bends when tension occurs. The end of the tube, which is not fixed, moves thus being a measurement of the pressure. Bourdon tubes with a number of superimposed coils of the same diameter (helical coils) are used for measuring high pressures.

Capsule element analog pressure gauges consist of two circular shaped, convoluted membranes sealed tight around their circumference. The pressure acts on the inside of the capsule and a pointer indicates the generated stroke movement. Pressure gauges with capsule elements are more suitable for gaseous media and relatively low pressures.

Diaphragm element analog pressure gauges combine both a chemical seal and a pressure gauge into one unit. Diaphragm elements are circular shaped, convoluted membranes that are either clamped around the rim between two flanges or welded in place. The measured media exerts a force on the diaphragm. A metal pushrod welded to the top of the diaphragm transmits the deflection of the diaphragm to the linkage. The linkage, in turn, translates the lateral motion of the push rod into a rotational motion of the pointer.