GENERAL FEATURES

OF

BAFCO HYDRAULIC-ELECTRONIC POSITIONING SYSTEMS

 

 

1.   BAFCO positioning systems are built to our strict standards for performance and reliability. BAFCO design features can include:

      ·        Non‑tie rod cylinder

·        End of stroke cushions to prevent valve shock at the highest travel speeds

·        Leak free cylinder shaft seal

·        Internally mounted position transducer

·        De-clutchable manual handwheel which allows any component including the cylinder to be serviced while process is operating

·        Hydraulic power units optimize the use of manifolds to provide quick access to control components and minimize the potential for leaks

·        Pressure piping above 1/4“dia. have all welded connections

·        Systems use metal-to-metal sealing surfaces with captivated elastomer seals.

·        No tapered pipe threads are used

·        Stainless steel filter elements are high capacity type capable of 3000 psi differential pressure without collapse

·        No filter bypass relief valves are used

·        Systems are thoroughly tested in our shop. You are invited to witness these tests

·        Hydraulic systems utilize stainless steel for all fixed piping and large surface area components, such as reservoirs

·        All manifolds are high strength aircraft‑grade aluminum anodized to protect from corrosion

·     Electronics, like our actuators and power units, are designed and built by BAFCO. You will never need to call anyone but BAFCO to resolve a problem, answer a question, or obtain the proper parts

·      Systems are virtually maintenance free. Only an annual filter change and accumulator precharge check are recommended.

 

2.      HYDRAULIC POWER/CONTROL UNIT SPECIFICATIONS OFFER:

      ·        All piping and reservoir are stainless steel

·        All manifolds are aircraft grade anodized aluminum

·        Variable volume positive displacement pressure compensated hydraulic pump

·        Accumulator storage for reserve strokes

·        Indications:

·        Pump discharge pressure

·        Control pressure ‑ (with above, gives pressure both sides of filters)

·        Oil level

·        Oil temperature

·        Pump shutdown on low‑low hydraulic fluid reservoir level

 

3.      THE THROTTLING CAPABILITY WOULD INCLUDE:

      ·        Control manifold with servo valve

·        Junction box with servo amplifier and position transmitter

·        Precision of this system provides resolution and repeatability of +/‑0.1%

 

4.   System is designed for long life under continuous operation with very little maintenance (i.e. ‑ change filter and check accumulator pre‑charge once per year).

 

5.   System is suitable for use in outside environments with no protection.

 

6.   Electrical components are suitable for use in many Class 1, Division 2 areas, (typically group C & D). Other classifications are available.

 

7.   All hydraulic connections are of leak‑free design. All static seals are metal to metal with captivated elastomer seals. All large pressure piping (over 1/4 “) have welded ends. All dynamic seals are zero pressure differential type to avoid leaks.

 

8.   Complete BAFCO positioning systems offer a long list of available features:

·        Modular electronics with fault indication LEDs.

·        Manual hydraulic control with remote/local switch

·        De-clutchable mechanical handwheel with provision for using an air motor.

·        Block and bleed valves with test ports on all pressure gauges and switches.

·        Separate contacts, which when open fail the valve to its safe end.

·        Indication:

·        With local electronic valve position, command signal and deviation for bumpless local/remote switching.

·        Mechanical valve position

·        Reservoir fluid level

·        Reservoir fluid temperature

·        Pressure both sides of filters

·        Alarm on:

·        Low reservoir fluid level

·        High reservoir fluid temperature

·        Low pump pressure

·        Loss of electrical power

·        Loss of command signal

·        Loss of power supply

·        Position deviation from command signal

·        Low accumulator pressure

·        All alarms are N.O. contacts and can be series wired for use as a common trouble alarm

·        Fail in position or to safe end (your choice) on:

·        Loss of position feed

·        Loss of command signal

·        Loss of power supply

·        Loss of pump pressure

·        Fail in position on:

·        Loss of main accumulator pressure

·        Test cycle with key lock, which allows operator to fast cycle the valve through a small movement to verify the system in working properly. Useful if valve sits in one position for extended periods.

·        Waveform generator with multiple settings for frequency and amplitude. Waveform offers protection from valve sticking via a small cycle that will not affect the process.

·        BAFCO failsafe valve is separate from and overrides all other controls and/or failures so that a valve can be made safe despite control, hydraulic or electric failure.

·        BAFCO failsafe reliability test system checks all failsafe system components including the failsafe valve spools without interrupting process normal operation.

 

 

 

Available hydraulic power supply

 

1.   Model 790/794 dedicated systems:

·        Single pump connected to dual filter pump manifold complete with pump suction shutoff valve, isolation valves, discharge pressure gauge and block/bleed valves, and accumulators.

·        Dual pumping system with both pumps connected to a common dual filter pump manifold with a suction shutoff valve for each pump, isolation valves, a common pressure gauge with block/bleed valves and accumulators.

·        Dual pumping system with each pump connected to its own single filter manifold with a suction shutoff valve, isolation valves, discharge pressure gauge and block/bleed valves and accumulators common to both pumps.

·        Dual pumping system as above except each pump manifold has a separate accumulator(s) direct connected. This allows maintenance on one pump/driver, filter or accumulator, while continuing to operate with the other pumping system with accumulator reserve power.

 

            Note: above filters are all high-pressure (3000 psi) filters.

 

2.   Model 717 central systems - In addition to the above systems the following features are available on larger capacity central pumping units:

·        Pump manifolds complete with suction shutoff valve, suction strainer, high-pressure filters, isolation and bleed valves.

·        Pumping systems with a separate suction strainer manifold with block valve and separate single or dual high-pressure filter manifold with isolation and bleed valves for each pump.

 

              3. Pump auto start:

·        Simple auto start where one pump is always main and the other is always the back‑up.

·        Auto start where either pump may be selected for main or back‑up service via a locally mounted selector switch.

 

            4.   Miscellaneous options:

·        Additional pressure switches for alarms, pump running indication or other uses. Motor starters (never included in base quote) normally supplied by customer so preferred brand is utilized.

·        Steam turbine driven main pump. This is an option normally reserved for central power units.