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Macam-Macam Valve

Sains, Teknologi dan Ekonomi Bisnis    Thursday, November 22, 2012

Macam-macam valve yg sering dijumpai di plant adalah sebagai berikut :
  1. Gate Valve, valve yg terdiri dari dinding yg mirip dg gerbang pagar. Pengoperasiannya adalah ditarik naik turun full dan tidak bisa digunakan setengah bukaan. Jadi aliran berhenti atau mengalir saja dan tidak bisa utk mengontrol besar kecilnya aliran
Keuntungan :
  • Kapasitas aliran tinggi
  • Biaya rendah
  • Desain dan operasi sederhana
  • Gesekan aliran thd valve sedikit
Kerugian :
  • Sulit dalam mengontrol aliran karena saat aliran masih mengalir harus dihentikan scr tiba-tiba
  • Kekuatan dari gate harus tinggi
  • Posisi penggerak buka tutup yg terus menerus bisa menyebabkan erosi
  • Hanya bisa digunakan utk buka full atau tutup full
"The kinds of valves often we know in plant such as :
      1. Gate Valve, valve consist of wall similar with fence gate. Operation is pulled up - down full and can't be used half opening. So flow is off or on only and can't to control large small flowrate
Advantages :
  • High flowrate  capacity
  • Low cost
  • Simple design and operation
  • Valve flow friction is slightly
Disadvantages :
  • Difficult to contol flowrate because time flowrate still flowing must be stopped suddenly
  • High of strength gate
  • Position of handle on / off continue done can  due to errosion
  • Only can be used to full open or close"
Gate Valve
     2. Plug valve, valve yg penghambatnya berbentuk silinder. Aplikasi utk fluida yg densitasnya besar
Keuntungan :
  • Operasi cepat
  • Kapasitas aliran besar
  • Harga murah
  • Kuat menahan fluida berat / lumpur
Kerugian :
  • Bahan silinder harus kuat
     "2. Plug Valve, valve that have cylinder like gate. Application for high density fluid
Advantages :
  • Quick operation
  • Large flow capacity
  • Low cost
  • Resistance to hold weight fluid / sludge
Disadvantage :
  • Material cylinder must be strong."
Plug Valve
      3. Globe Valve, disk yang bergerak tegak lurus sehingga saat diangkat naik fluida mengalir dan saat turun kran tertutup. Digunakan utk mengatur laju aliran fluida
Keuntungan :
  • Akurat dalam kontrol aliran
  • Kemampuan menutup baik
Kerugian :
  • Pressure drop tinggi
  • Harga mahal
       "3. Globe Valve, disk moving vertical so if disk up fluid is flow and disk down mean close valve. Used to regulate flowrate fluid 
Advantages :
  • Accurate in flow control
  • Good capability to close
Disadvantages :
  • High pressure drop
  • Expensive cost"
Globe Valve
      4. Ball Valve, valve yg dilengkapi bola yg berlubang sbg penghalangnya. Jadi saat posisi lubang sejajar aliran maka valve membuka dan saat posisi lubang tdk sejajar aliran maka kran menutup.
Keuntungan :
  • Harga murah
  • Kapasitas aliran tinggi
  • Tidak membutuhkan pelumasan
  • Pembersihan mudah
  • Rendah kebocoran
  • Bisa digunakan utk tekanan dan suhu tinggi
Kerugian :
  • Sulit dalam pengembalian secara halus dari terbuka ke tertutup karena derasnya aliran fluida melewati lubang
      "4. Ball Valve, valve is completed hollow ball. So if position of hollow equal with flow mean open valve and if position of hollow ball no equal with flow mean close valve 
Advantages :
  • Low cost
  • High flow capacity 
  • No lubricant
  • Easy maintenance
  • Low leakage
  • Can be used for high pressure and temperature
Disadvantage :
  • Expensive return smoothly from open to close due to high flowrate of fluid passing hole"
Ball Valve
      5. Butterfly Valve, digunakan utk aliran fluida bertekanan rendah. Terdiri dari disk tipis yg ditengahnya terdapat sumbu putarnya
Keuntungan :
  • Kapasitas aliran besar
  • Perawatan dan harga murah
  • Kompak dan ringan
Kerugian :
  • Tidak bisa digunakan utk rate aliran tinggi
       "5. Butterfly Valve, used for fluid with low pressure. Consist of slim disk with middle there is shaft rotate. 
Advantages :
  • High flow capacity
  • Low cost and maintenance
  • Compact and light
Disadvantage :
  • Can't be used for high flowrate"
Butterfly Valve
      6. Diaphragm Valve, bisa digunakan utk mengatur laju aliran dan bisa digunakan utk on / off aliran. Efektif utk material kasar
Keuntungan :
  • Harga murah
  • Tahan penyumbatan dan korosi
  • Tidak terjadi kebocoran
Kerugian :
  • Umur diafragma tergantung pemakaian
       "6. Diaphragm Valve, can be used to regulate flowrate and also used for on / off flowrate. Effective for rude material 
Advantages :
  • Low cost
  • Resistance dirt and corrosion
  • No leakage
Disadvantage :
  • Diaphragm life is dependent application"
Diaphragm Valve
       7. Pinch Valve, cocok digunakan utk fluida kasar
Keuntungan :
  • Harga dan perawatan murah
  • Tahan korosi dan abrasi
  • Desain sederhana
Kerugian :
  • Sulit dalam pengukuran
  • Terbatas utk aplikasi kondisi vakum
       "7. Pinch Valve, used for rude material 
Advantages :
  • Low cost and maintenance
  • Resistance corrosion and abbrasion
  • Simple design
Disadvantages :
  • Difficult measuring
  • Limited vacuum application"
Pinch Valve
      8. Check Valve, digunakan utk membuat aliran ke satu arah saja dan membuat aliran tidak bisa balik. Aplikasi biasanya pada sisi suction pompa sentrifugal
Keuntungan :
  • Tahan terhadap benda kasar
  • Turbulensi dan tekanan dlm valve rendah
Kerugian :
  • Rate yang tinggi dapat membanting valve dan jika terus menerus penahannya bisa patah
       "8. Check Valve, used to make flow in same direction and make flow can't reverse. Application usually i suction side centrifugal pump 
Advantages :
  • Resistance to rude material
  • Low turbulence and pressure in the valve
Disadvantage :
  • High flowrate can strike valve and if done continue can be broken"
Check Valve
      9. Relief Valve dan Safety Valve, valve yg digunakan utk pengamanan alat dari bahaya, misalnya kelebihan tekanan dll. Relief Valve bekerja membuka secara perlahan dan menutup perlahan apabila kondisi normal, cocok utk fluida liquid. Safety valve bekerja membuka secara cepat dan langsung full buka dan kembali menutup dg cepat saat kondisi normal, cocok utk fluida gas.
Keuntungan :
  • Desain gagal aman, jadi kalau alat tidak bekerja maka proses tetap aman
  • Tidak memerlukan energi dari luar utk menggerakkan valve
       "9. Relief Valve and safety Valve, valve is used to protect instrument from hazard, like excess pressure etc. Relief valve working slowly open if there is problem and slowly close if normal condition, good for liquid. Safety valve working quick open and direct full open and return close quickly if normal condition, good for gas.

 Advantages :
  • Save failure design, if instruments not working so procces is save
  • No need external energy for moving valve"
Relief and Safety Valve
      10. Control Valve, dilengkapi dg pegas jadi saat ada kondisi melebihi set point, pegas akan melar dan valve terbuka dan kondisi normal spring kembali

    "10. Control Valve, completed spring with working if condition excess set point, spring will elastic and valve is open and if normal condition spring will return "
Control Valve

Kutip Artikel ini sebagai Referensi (Citation):
Feriyanto, Y.E. (2012). Macam-Macam Valve, Best Practice Experience in Power Plant. www.caesarvery.com. Surabaya

Referensi:
[1] Feriyanto, Y.E. (2012). Best Practice Experience in Power Plant. Surabaya
[2] Standar Handbook of Plant Engineering, Dressser Valve Divission : Stafford Texas

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