Torqflow Hidrolik Circuit D85ESS-2

Sahabat teknisi, kali ini saya akan sedikit menjelaskan beberapa fungsi valve yang ada pada hidrolik circuit torqflow transmission. Sebagai contoh untuk postimg kali ini, saya ambil circuit torqflow transmission pada bulldozer D85ESS-2 Komatsu.

   

1.  Transmission case.               11.  Torque converter.                         A.  Plug for transmission 

2.  Transmission oil strainer.      12.  Torque converter                               Mission clutch pressure

3.  Transmission pump.                    regulator valve.                            B.  Plug for 1st clutch  

4.  Transmission oil filter.          13.  Oil cooler.                                         pressure.

5.  Modulating valve.                 14.  Transmission                                C.  Plug for torque    

6.  Quick return valve.                     Lubrication valve.                                converter relief   

7.  Reducing valve.                   15.  Transmission.                                    pressure.

8.  Speed valve.                       16.  P.T.O lubrication.                          D.  Plug for torque

9.  F - R valve.                         17.  Torque converter                               converter pressure.

10. Torque converter relief              case.                                           E.  Plug for torque

     valve.                                18.  Oil strainer.                                       Converter oil    
                                             19.  Scavenging pump.                              temperature

1. Modulating Relief Valve, fungsinya :

- Mengatur dan membatasi maximum oil pressure yang akan digunakan oleh setiap transmission clutch. 

- Bersama - sama dengan quick return valve memodulate pressure sehingga dapat  mengurangi kejutan pada clutch ( slow engage ) dan sock padaunit yang dapat memungkinkan panjang umur dari setiap komponen.

- Mengatur ( waktu ) oil flow yang menuju ke torque converter.

   

2. Quick Return Valve, fungsinya :

Mengatur langkah gerak dari sleeve dari modulating valve ( dengan mengatur   flow oil kesleeve dan ke drain ) sehingga dapat terjadi cepat dalam   disengage dan lambat / pelan - pelan dalam engage setiap transmission   clutch.

   

3. Reducing Valve, fungsinya :

Mengatur arah aliran oil yang akan masuk ke rotary clutch.

   

4.Speed Valve, fungsinya :

Mengatur arah aliran oil ke setiap speed clutch dan drain.

  

5.Safety Valve, fungsinya :

Sebagai penyelamat, jangan sampai unit bergerak ( maju / mundur ) sebelum   dikehendaki operator pada saat engine di start.

6.Directional Valve, fungsinya :

Mengarahkan aliran oil ke directional clutch ( forward / reverse ) dan drain.

Engine Emissions Compliant TIER 3

The new generation ( Tier 3/Stage III-emissions compliant ) engines now on the market from leading construction equipment suppliers provide very low emissions levels to meet the latest environmental regulations. But how well do they deliver in terms of fuel economy and long-term durability? Angus Fotheringham, Komatsu Australia’s Business manager, general construction, provides some answers.

The current generation of Tier 3-compliant engines have been designed to meet very stringent emissions regulations put in place by environmental agencies in Europe, the US and Japan – and as such, represent the pinnacle of construction equipment engine technology.

Having said that, we can expect to see even more work on construction engines over the next few years, to achieve Tier 4 regulations (coming into force in the US between 2011 and 2015). Already, the on-highway transport industry is rolling out Tier 4-compliant engines.

To meet the current Tier 3 requirements, the current generation of engines use various methods to minimise the levels of nitrous oxide (NOx), particulate matter (PM) and other emissions that pollute the air.


Common to all engine manufacturers’ solutions are very precise electronic engine management systems that can very accurately measure and meter the levels of fuel and air being delivered to the combustion system.

As with all modern diesels, critical factors include clean fuel and correct filtration management, the correct engine lubricants, and proper engine maintenance management practices.

However, in achieving the lower emissions required under Tier 3, different manufacturers have adopted different approaches.

In Komatsu’s smaller ecot3 construction equipment engines, Tier 3 compliance is being achieved primarily through sophisticated electronic engine management.

In its larger construction equipment engines, Komatsu, as with most other major engine manufacturers, has opted for what is known as cooled exhaust gas recirculation (EGR) as part of its ecot3 solution to comply with lower emissions standards.

As its name implies, EGR involves recirculating a portion of cooled exhaust gases so that the NOx and PM levels are further reduced when the exhaust gases are released to the atmosphere. This process also helps to reduce any unburnt particulates during the combustion process.

EGR technology is not new; it has been around for at least 30 years, and is regarded as reliable and well proven – although today it is applied to modern engines in a far more technically advanced manner. In addition, EGR does not require the fitting of a particulate filter, which requires periodic replacement.

But in addition to EGR, Komatsu’s new generation ecot3 engines combine a number of other advanced-technology solutions. These include:

• A high-pressure common-rail multi-stage fuel injection system
• A patented piston/cylinder design to deliver more complete burning of fuel
• An advanced engine management system that controls the burning of emission-causing particulates inside the cylinder.

These processes, combined with a liquid-cooled heat exchanger, significantly cool the recirculating exhaust gases before they re-enter the cylinder, resulting in a system that runs more efficient than other EGR-based engines.

In addition, Komatsu’s ecot3 unique cylinder design results in greatly improved combustion, for a far more efficient fuel burn.

The end result of this technology, in addition to significantly lower emissions, is reduced fuel consumption – a major cost-saving benefit in today’s environment of high fuel costs.
So what are the key factors in engine life? There are five critical factors that all diesels – no matter what their age or technology – require for efficient, reliable and long-term operation. These are:

• The right operating temperature (in other words, correct cooling)
• Clean recommended engine oil
• Clean air
• Clean fuel that meets the required standards
• Regular maintenance (including oil analysis).

But there is one more factor that is often overlooked: Fuel burn.

An engine that burns more fuel – in other words, that is less fuel efficient – will have a shorter life than an engine burning less fuel.

Fuel burn, the amount of diesel that goes through an engine during its life, has a direct correlation to engine longevity. The more fuel an engine burns, the harder the components are working, and the sooner it will wear out.

Conversely, a more fuel-efficient engine – one that burns less specific fuel – won’t be working so hard and will have a longer life (all those other factors mentioned above being equal).

That’s why good fuel efficiency at optimum performance should be a key element that customers look at when choosing a machine.

Not only will the machine be kinder on your hip pocket every time you go to fill it up, but – provided you look after it and comply with the manufacturer’s maintenance requirements – you will get a longer life from it. That’s an important consideration when you think that approximately 30% of a machine’s repair costs over its life are in the engine.

In addition, the more fuel-efficient a machine is, the fewer emissions it will be producing per tonne of production, simply because it’s burning less fuel.

And that’s why Komatsu has paid considerable attention to developing Tier 3 engines that are more fuel-efficient than their Tier 2 predecessors.

As an example, Komatsu’s recently released WA600-6 wheel loader, with our new ecot3 Tier 3 engine is already proving more fuel-efficient in heavy duty quarrying face loading and load-and-carry operations in Australia than its Tier 2 predecessor.

In contrast, there are some Tier 3 engines around from other manufacturers which burn more fuel than their Tier 2 predecessors.

All this places Komatsu in a leading position in the move to Tier 4 requirements in the next few years, with Japan looking to demand the most stringent emissions requirements of any country.

And unlike other manufacturers’ solutions, Komatsu’s ecot3 technology is already “Tier 4 ready”, and therefore well positioned to meet these requirements, at the same time delivering unmatched fuel efficiency with longer engine life and better reliability.

Kesempatan Berkarier Untuk Newmont Indonesia

Founded in 1921 and publicly traded since 1925, Newmont (www.newmont.com) is one of the largest gold companies in the world. Headquartered in Denver, Colorado, the company has approximately 34,000 employees and contractors, with the majority working at Newmont’s core operations in the United States, Australia, Peru, Indonesia and Ghana. Newmont is the only Gold company listed in the S&P 500 index and in 2007 became the first company selected to be part of the Dow Jones Sustainability World Index. Newmont’s industry leading performance is reflected through high standards in environmental management, health, and safety for its employees and creating value and opportunity for host communities and shareholders.
Job Description
Senior Advisor Mine Maintenance - Contract Assignment
Job Number:
110807
WORKING CONDITIONS/REGULATORY REQUIREMENTS:
The position exists in a remote jungle environment in a sparsely populated area in Indonesia. The incumbent may undertake business travels to various Corporate mine sites and places on the company’s behalf. Require to access mining areas and rough terrain on a daily basis.
Qualifications
REQUIRED TECHNICAL SKILLS, TRAINING & EXPERIENCE:
Mandatory Requirements for this position:
-B.S. degree in Electrical Engineering or relevant Trade Certificate.
-5 (five) years experience in a supervisory position in the mining industry, or an equivalent combination of training and experience are necessary.
DIMENSIONS OF THE POSITION:
Position supervises Senior Foremen and Foremen in the day to day activities associated with the electrical maintenance of Electric Rope Shovels, Blast Hole Drills, Pit Power Distribution, Dispatch and In Pit pumping Systems.
PURPOSE:
To coordinate the activities of NNT maintenance and Contractor maintenance work across shifts and to ensure that adequate resources are available to meet production and maintenance needs.
ESSENTIAL DUTIES, included but not limited to:
-Comply with all PTNNT Occupational Health, Safety and Environmental requirements as well as those required under the Decree of the Ministry of Mines and Energy Number 555.K/26/M.PE and the Decree of the Ministry of Mines and Energy Number 1211.K/008/M.PE/1995.
-Comply with all SHLP, Environment and Social Responsibility requirements under Newmont Asia Pacific Integrated Management System, Newmont vision and values.
-Accept personal responsibility for the health and safety of every mine worker under or assigned to his supervision.
-Implement training procedures in line with PTNNT Succession Planning Policy.
-Sets goals and coordinates the activities of Electrical Maintenance Foremen in the field and in the workshop to ensure that scheduled maintenance and emergency repairs are accomplished with minimal disruption to the operation.
-Ensures that adequate resources are available to meet scheduled maintenance and repair needs.
-Reviews all maintenance schedules and coordinates activities with other departments in order to ensure optimal equipment and operation availability to meet business needs.
-Monitors and reviews costs; establishes and maintains budgets; recommends replacement of updating of equipment.
-Reviews and updates departmental procedures and policies, administers discipline, enforces company policy, and ensures compliance with state, federal, or other jurisdictional laws.
-Responds to emergencies that could cause injury to personnel or loss of operational efficiency.
The duties and responsibilities listed above are representative of the nature and level of work assigned and are not necessarily all inclusive.
This is a 24 month contract assignment.
Job
: Operations - Surface
Primary Location
: ASIA-Indonesia
To apply Online, pls Click : newmont career

Lowongan Kerja Migas Untuk CHEVRON, Australia

Job Title: Expression of Interest- Process/Chemical Engineering
Requisition Number: 05854633
Employment Status: Full Time
Site/City: Perth
State: Western Australia
Country: Australia

Overview of Position:
Chevron is one of the world’s leading integrated energy companies and through its Australia subsidiaries, has been present in Australia for almost 60 years.
Position Details:
Our company’s foundation is built on our values, which distinguish and guide our actions. We conduct our business in a socially responsible and ethical manner. We respect the law, support universal human rights, protect the environment and benefit the communities where we work. As a company, our vision is to be the global energy company most admired for its people, partnership and performance.

With over 2,500 employees, Chevron Australia is leading the development of the Gorgon and Wheatstone natural gas projects. We also manage an equal one sixth interest in the North West Shelf Venture and are a participant in the proposed Browse LNG Development. Additionally we operate Australia’s largest onshore oilfield on Barrow Island, along with the Thevenard Island oilfields.
It has never been a more exciting time to join Chevron Australia with our two mega projects moving towards operations. As we continue to grow, we are anticipating ongoing vacancies for process/chemical engineering professionals with demonstrated experience in the oil and gas industry.
In applying for an expression of interest, we will retain your application and make contact with you should a suitable position arise. In addition, we also encourage you to regularly check our website and also register for alerts for current vacancies.

If you are interested in this position, you must respond online. No phone, fax or email inquiries from potential applicants, external recruiters or other interested parties, please.
Chevron is an Equal Opportunity Employer
Click here to Apply Online : Chevron Career

Deskripsi Dan Type Gear Pump

Pompa roda gigi ( gear pump ) banyak sekali dipergunakan pada sistem karena pompa ini sangat sederhana dan ekonomis. Pompa ini tergolong pompa fixed displacement.

Gear pump digolongkan menjadi dua yaitu :

(-) Internal Gear Pump.

Konstruksi internal gear pump atau trochoid pump.

(-) External Gear Pump.

Untuk unit - unit Komatsu sistem hidroliknya banyak memakai jenis external gear pump ini. Konstruksi external gear pump terlihat pada gambar.

Secara garis besar, external gear pump dapat dibagi dalam dua jenis :

~ Fixed Side Plate Type Gear Pumps.

Side plate pompa ini tidak dapat bergeser-geser. Kontruksinya ada yang jadi satu dengan housing, dan ada pula yang terpisah tetapi di ikat terhadap housingnya. Pompa ini mempunyai discharge pressure antara 30 Kg/Cm² sampai dengan 125 Kg/Cm². Komatsu menamakan pompa jenis ini tipe FAL/R dan GAL/R.

~ Movable Side Plate Type ( Pressure Balancing Type Gear Pumps ).

Side plate pompa ini dapat bergeser semakin menjepit gear bila      tekanan naik. Dengan demikian maka internal leakage diperkecil sebab side clearance juga kecil. Specific Discharge Pressurenya lebih besar dari 140 Kg/Cm².

Gear pump yang dipergunakan dalam unit-unit Komatsu berbeda-beda jenisnya disesuaikan dengan fungsinya. Untuk itulah maka external gear pumps diklasifikasikan dalam 5 ( lima ) jenis yaitu :

        * FAL/R dengan tekanan 30 Kg/Cm²

        * GAL/R dengan tekanan 125 Kg/Cm²

        * PAL/R dengan tekanan 140 Kg/Cm²

        * KAL/R dengan tekanan 175 Kg/Cm²

        * SAL/R dengan tekanan 210 Kg/Cm²

Kesempatan Berkarier Untuk PT. Darma Henwa Tbk

We are a leading integrated mining services company for more than 19 years. To support our expansion, we urgently require qualified, professional and highly motivated candidates to join our team for following positions:

1. Maintenance Superintendent
2. Finance Superintendent
3. Logistics Superintendent
4. Coal Hauling Foreman
5. Surveyors
6. Safety Officers
7. HR Staff
8. Finance Staff
9. Maintenance Staff
10. Logistics Staff

All candidates should be willing to be placed on site
Should you meet our requirements, please submit your complete CV in PDF or MS-Word format not more than 350KB to:
recruitment@ptdh.co.id

Please put the position name as your email subject
To know more about our company you are invited to visit www.ptdh.co.id
Only qualified candidate match with the above mentioned qualifications will be notified for further process
Expiry date: January 10, 2012

Klasifikasi Pompa Hidrolik

Semua pompa menimbulkan aliran ( flow ). Prinsipnya operasinya disebut DISPLACEMENT  “ dimana zat cair atau fluida diambil dan dipindahkan ke tempat lain. Secara umum pompa mengubah tenaga mechanical menjadi tenaga fluida hidrolik. Sedangkan yang dimaksud dengan DISPLACEMENT adalah volume zat cair yang dipindahkan tiap cycle ( putaran ) dari pompa.

Klasifikasi Pompa.

    

Pada dasarnya pompa hirolik diklasifikasikan menjadi :

a. Non positive displacement

Yang dimaksud dengan pompa NON POSITIVE DISPLACEMENT ialah bila pompa mempunyai karakteristik :

- Internal leakage besar.

-Perubahan tekanan mempunyai pengaruh yang besar terhadap kapasitasnya

    

b. Positive displacement.

Yang dimaksud dengan pompa POSITIVE DISPLACEMENT ialah bila pompa mempunyai karakteristik :

-   Internal leakage kecil ( untuk mendapatkan ini dibuat SEAL atau presisi ).

-   Perubahan tekanan berpengaruh kecil terhadap kapasitasnya ( dengan dibuatnya presisi / SEAL, akan melawan kebocoran pada saat tekanan naik ).

Pompa positive displacement sendiri terbagi menjadi beberapa type, yaitu: 

• Gear pump: bersifat murah, memiliki ketahanan yang lama (awet), sederhana pengoperasiannya. Tetapi kelemahannya adalah memiliki efisiensi yang rendah, karena sifat pompa yang ber-displacement tetap, dan lebih cocok untuk digunakan pada tekanan di bawah 20 MPa (3000 psi).  

• Vane pump: murah dan sederhana, biaya perawatan yang rendah, dan baik untuk menghasilkan aliran tinggi dengan tekanan yang rendah. 

• Axial piston pump.Satu jenis pompa hidrolik yang menarik adalah axial piston pump. Pompa ini dapat berjenis swashplate atau juga checkball. Jenis pompa ini didesain untuk dapat belerja pada displacement yang bervariasi, sehingga dapat menghasilkan aliran dan tekanan fluida hidrolik yang bervariasi sesuai dengan kebutuhan. Jenis yang paling banyak digunakan adalah swashplate pump. Pompa ini dapat kita ubah sudut swashplate-nya untuk menghasilkan langkah piston yang bervariasi tiap putaran. Jika sudut semakina besar, akan menghasilkan debit aliran yang besar dengan besar tekanan yang lebih kecil, dan begitu pula sebaliknya.   

• Radial Piston Pump: digunakan untuk menghasilkan tekanan fluida hidrolik yang tinggi dengan debit aliran yang rendah. 

Kesempatan Berkarier Untuk PT. PERTAMINA Unit Kerja Cepu

PT. Pertamina EP Cepu (PEPC) is a subsidiary of PT Pertamina (Persero) with operations in Cepu Block, Bojonegoro, East Java, in partnership with Mobil Cepu Ltd. and local governement-owned companies. PEPC is a fast growing national oil and gas company and is expanding its operations. In order to meet its workforce requirements, we are looking for qualified experienced professionals for immediate employment.

General qualifications:
• Proficient in English both oral & written
• Willing to work hard and under pressure in individual and/or team environment
• Willing to work in remote areas
• Computer literate
• Age 28 - 35 year
• Bachelor degree in related disciplines from reputable universities
• Min 5 years experience in related fields, preferably in oil & gas industry
• Good communications and interpersonal skills


Specific qualifications:

1. Electrical & Instrument Engineer
• Bachelor degree in electrical engineering/electronic & Instrument engineering/physics engineering
• Competence in providing reviews and recommendations during design and construction of electrical devices and instruments, do technical analysis to the entire device.
• Competence in the design of electrical & instrument system for oil & gas production facilities Familiar with INSTRUCAL and ELECTRICAL DESIGN softwares.

2. Process Engineer
• Bachelor degree in Chemical Engineering/Gas & Petrochemical Engineering
• Competence in planning and making process flow, tooling design and development, manufacturing process and certification testing
• Familiar with HYSIS, ACCE, PIPESIM, FLARENET, PIPEPHASE, AUTOCAD software.

3. Petroleum Engineer
• Bachelor degree in Petroleum Engineering
• Competence in analyzing and performing probabilistic forecasts, forecasting coordination for oil & gas reserves, deliverability and optimization of gas production as well as identify areas for improving reservoir recovery and reliability

4. Project Planning Controller
• Bachelor degree in engineering
• Ability to create a master schedule and summary, assign engineer to each EPC, develop a method of cost control and conduct audits to ensure basic control rules applied
• Familiar with project control software such as Microsoft Project, Primavera

5. Civil Engineer
• Bachelor degree in civil engineering
• Competence in designing infrastructure and other civil works, performing calculations and analysis of structure, documenting the results and progress of work and making report of civil works, to ensure the work can be completed on target

6. Mechanical (Pipeline) Engineer
• Bachelor degree in mechanical engineering
• Competence in managing oil & gas project activities such as engineering design, construction, installation, inspection, start up, test and commissioning.
• Familiar with AUTOCAD, PIPESIM softwares.

7. Drilling Engineer
• Bachelor degree in petroleum/mechanical engineering
• Competence in drilling stem testing and well cost estimation, confirming the predictions of drilling subsurface and keeping abreast of the latest technology, equipment and techniques.

8. Drilling Material Engineer
• Bachelor degree in engineering/material technology
• Competence in procurement of drilling equipment, tools and materials, providing recommendations for logistics strategy, and ensuring equipment and materials sent in accordance with contract specifications

9. Drilling Operation Engineer
• Bachelor degree in petroleum/mechanical engineering
• Competence in drilling operation work planning, monitoring, providing recommendations, evaluating the test results, preparing drilling program, and evaluating the estimated cost of drilling operations.

10. Contract Specialist
• Bachelor degree in Law
• Ability to arrange draft contracts, negotiate contracts, compile proposals, evaluate the performance of subcontractors and prepare renew contracts, legal issues and ensure the legality of contracts

11. Recruitment & Training Sr. Officer
• Bachelor degree in Law/Management/engineering/psychology
• Experience in recruitment and training activities at headquarters and in the field, coordinate with relevant parties to implement the activities

12. HR Services Officer
• Bachelor degree in Law/Management/engineering/psychology
• Experience in receiving and verifying documents related to vacation requests, medical claims, business travel and other reimbursements, and anything that related with personnel administration activities

13. Procurement, Office & Logistic Assistant Manager-General Services
• Bachelor degree in related discipline
• Ability to coordinate all activities of procurement and logistics services/ goods of non engineering/production, ensuring the procurement process carried out in accordance with policies, standard and procedures

14. Information Technology Assistant Manager
• Bachelor degree in Management Information System/Information Technology
• Experience in analyzing, designing, constructing, maintaining and managing IT infrastructure, database, systems and operational procedures to ensures all applications and IT system run effectively and efficiently

15. Corporate Safety & Security Superintendent
• Bachelor degree in industrial/environmental engineering
• Certification in HSE & Security
• Experience in planning, Implementing, and coordinating safety program, requiring application of engineering principles and technology, to prevent or correct unsafe conditions in working area

16. Quality Management Officer
• Bachelor degree in engineering
• Ability to monitor the quality and technical support quality management, especially for all the activities in development (engineering) and operation.

17. Budget Controller
• Bachelor degree in petroleum/mechanical engineering/Management/Finance
• Ability to develop, research, analyze and run the company approved budget for operational costs by taking into account financial resources, including allocating resources and estimating future expenditure.

18. Cost & Schedule Coordinator
• Bachelor degree in petroleum/mechanical engineering/Management/Finance
• Ability to create project reports and other related administrative work. providing technical support services to calculate quantitative risk analysis of expenses accurately with appropriate contingency schedule.

19. Contract Gas Officer
• Bachelor degree in engineering/law
• Ability to arrange draft contracts for gas, negotiate contracts, compile proposals, evaluate the performance of subcontractors and prepare contracts, legal issues and ensure the legality of contracts especially for gas, supporting gas marketing.

20. Account Payable/Account Receivable Supervisor
• Bachelor degree in Finance/Accounting
• Experience in the reconciliation and analysis associated with the account AR/AP, ensure the accuracy of recording transactions and reporting presented on time

21. Accounting Operation Supervisor
• Bachelor degree in Accounting
• Experience in coordinating, monitoring, reviewing cost analysis, margins, including ensuring compatibility between cost and activities; Coordinating the preparation of the presentation system analysis, data and information accurately and be accessed by timely management.

22. Treasury Officer
• Bachelor degree in Accounting
• Experience in managing “cash balance” using planning of payment by taking into account the availability of corporate funds, as well providing inputs/suggestions to anticipate financial market changes/external factors that may on the fund company.

Please submit your application indicating position number applied in the e-mail subject. Please also include your CV, recent photograph, and expected salary by e-mail on 6 January 2012 at the latest to: recruitment.epcepu@pertamina.com

Sirkuit Dasar Open Center dan Close Center

Sahabat teknisi, kembali lagi pada pembahasan sistem hidrolik. Dalam suatu sistem hidrolik, hubungan antar komponen – komponennya dibagi   menjadi dua macam sistem, yaitu sistem open centre dan sistemclose centre.

Dewasa ini ada dua jenis sistem hidrolikyang dikembangkan untuk dipakai di   unit- unit traktor :

1.  Open Center System

Dalam sistem bila control valve dalam keadaan netral, maka aliran oli disuplai   oleh pompa langsung dikembalikan ke tangki hidrolik lagi. Pada saat itu,   flownya maximum sedangkan pressurenya nol.

2.  Close Center System.

Bila control valve dalam keadaanneutral maka saluran dari pompa tertutup.   Dengan demikian maka tekanan antara pompacontrol valve akan naik sampai   batas tertentu kemudian pompa berhenti mensuplai oli ke sistem. Jadi bila

control valve neutral ( tertutup di tengah ) maka pompa akanneutral ( tidak   mensuplai oli).

Dalam hal ini bila control valve neutral maka pompa akan mensuplai oli sampai   tekanan naik pada batas yang sudah ditentukan kemudianpressure tersebut   dimanfaatkan atau menghentikan sama sekali untuk menjagaagar tekanan kerja sistem konstan.

Pada keadaan lain akan sama kejadiannya bialcontrol valve digerakkan dan   piston bergerak sampai akhir langkahpiston hydraulic cylinder. Dengan   demikian maka tekanan sistem akan naik dan bila sudah mencapai batasyang   sudah ditentukan maka suplai pompa dikurangi atau dihentikan sama sekali   untuk menjaga tekanan dalam sistem agar tetap pada tekanan maksimum   sistem.