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DWS Offers a Wide Range of Pumps for Petroleum, Petrochemical & Gas Industries
API 675 is the standard related to the positive displacement pumps with integrated controlled capacity. This plays an important role in the safe and efficient operation of many industrial plants.
The American Petroleum Institute (API) drives standards and quality among energy companies. They develop, maintain, and provide organizations with unanimous standards for these key industries.
Fully API 675 Compliant
Any unplanned downtime affects the bottom line regardless of your industry. Lost time incidents (LTIs) not only stop production, but the subsequent investigations and safety audits become additional overhead. The selection of process pumps using robust global standards such as ISO and API is key to meeting stringent industry criteria. This can be accomplished with appropriate margins for safety and environmental protection.
Using API standards to design pumps is a guarantee that they are reliable, efficient, and perform well with cost-effective operation.
API 675 meets the requirements for Positive Displacement Pumps, Reciprocating Pumps, and Controlled Volume pumps. Specifically, they are used in the petroleum, petrochemical, and gas industries.
These API 675 pumps are designed with:
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Hydraulic diaphragm
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Packed plunger
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Rotary positive displacement pumps are not included
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Diaphragm pumps that use direct mechanical actuation are also excluded
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Milton Roy has been designing API 675 pumps for over 60 years. Our Industrial and High-Pressure pump ranges are fully compliant with the API 675 standard.
Features of API 675 Pumps
Positive Displacement Pump
Positive displacement pumps (PDP) capture a moving fluid in a cavity and then discharge that fixed amount of fluid. The displacement of fluid takes place with some parts such as a plunger, piston, diaphragm, etc. Some of these pumps have an expanding cavity at the suction side and a decreasing cavity at the discharge side. The liquid is sucked at the inlet side when the cavity expands and discharges when the cavity decreases.
Reciprocating Pump
In general, a reciprocating pump has a higher efficiency than a centrifugal pump. Reciprocating pumps are generally applied in low-flow and high-discharge pressure environments.
DWS is an industry leader in the production of reciprocating pumps. They consist of a power end and a liquid end connected by a frame. Flow rates range from 0.09 l/h to 48 m3/h (0.04 gph to 211 gpm). Discharge pressures are available up to 1,034 bar (15,000 psi).
Liquid End Design
Liquid end designs include hydraulic diaphragm liquid end and packed plunger liquid end varieties.
Hydraulic-driven diaphragm
Packed plunger
Packed plunger
Controlled Volume Pump
Pump capacity can be adjusted by changing the pump stroking speed or the stroke length.
Stroke Speed
The stroke speed is pre-defined by the motor rotation speed and the mechanical gear ratio (worm & wheel).
Stroke Length
Milton Roy offers three primary technologies to vary the stroke length.
Hydraulic By-Pass Drive
Capacity Stroke Control
The end-user can adjust the stroke length by manually rotating the adjustment knob or remotely controlling the flow variation. This can be done by installing an Actuated Capacity Controller (ACC). This ACC is connected mechanically to the adjustment shaft and can be piloted remotely.
The end-user can adjust manually the stroke length, by rotating the adjustment knob.
The end-user can also pilot remotely the stroke length by using an Actuated Capacity Controller (ACC)
Accuracy
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The pump flow rate shall be adjustable over the specified turndown ratio (min. 10:1) while the pump is running
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The rated capacity shall be at least 110% of the maximum capacity specified
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The steady-state accuracy within ±1%, applies over the turndown ratio
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The linearity shall not exceed ±3% of the rated flow over the specified turndown ratio
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The flow repeatability shall be within ±3% of the rated flow over the specified turndown ratio
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The graph below represents the performance of a selected pump that complies with the API 675 standard in terms of steady-state accuracy, linearity, and repeatability along the 10:1 flow variation:
Safety Features
The API 675 standard requires the design of several safety features to protect the pump from failure.
Internal Safety Pressure Relief Valve
The API 675 diaphragm pumps are all equipped with an internal hydraulic over pressure system to protect the pump of the pump drive mechanism from excessive discharge pressure.
The internal pressure relief valve setting shall be at least 10 % or 175 kPa (25psi) over the rated discharge pressure, whichever is greater.
This internal safety pressure relief valve is not meant to protect the installation.
The API 675 standard recommends to install a PLV with all positive displacement pumps, on the discharge piping to protect the installation.
Automatic Self-Protection System for Hydraulic Diaphragm Design
In the API 675 standard with the hydraulic diaphragm pumps, the process fluid is isolated from the plunger by an actuated flat or shaped diaphragm.
DWS designed a special Mechanically Actuated Refill System pilot valve (called MARS pilot valve) in addition to the hydraulic diaphragm. This MARS pilot valve prevents the risk of diaphragm failure due to a closed suction isolation valve or an obstruction in the suction line.
The MARS pilot valve maintains a constant volume of hydraulic oil between the plunger and the diaphragm. It does this by automatically refilling the displacement chamber to compensate for the missing volume of oil. This eliminates the risk of diaphragm stretching and premature diaphragm wear, prolonging the lifetime and making the process safer.
Single and Double Diaphragms
DWS offers either a single or double diaphragm solution, in PTFE or stainless steel material to cover a large range of process fluid compatibility.
In addition to the double diaphragm design, DWS offers several solutions to secure the process from any risk of leakage:
– A pressure gauge can be connected for local checks by maintenance.
– A pressure switch can be connected for remote and automatic checks from a central control room.
– A pressure transmitter can be connected for remote and automatic control.
– A pressure gauge can be installed together with either a pressure transmitter, for the ease of local and remote monitoring.
For both single and double diaphragm solutions, DWS recommends PTFE or stainless steel materials. This ensures a large range of process fluid compatibility for your pumps.
Reliability
The API 675 standard recommends testing the pump, to ensure a high level of reliability.
DWS can perform the following unit tests (optional), to ensure the overall quality and reliability of each produced pump:
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Hydrostatic test
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Performance test
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Mechanical running test (if specified by the customer, 1-2-3-4 hours)
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Origin Material Certificate 2.2 – 3.1 – 3.2
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NPIPR test (Net Positive Inlet Pressure Required)
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MASP test (Minimum Allowable Suction Pressure)
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NDE (Non-Destructive Evaluation: radiographic, ultrasonic, etc.)
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PMI test (Positive Material Identification)
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Paint tests (thickness, adhesion, etc.)
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Vibration test
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Noise test
The DWS Difference
API 675 pumps are a great option for oil and gas, chemicals, and general industries. They are designed to transfer fluids in a controlled and safe manner with a high level of accuracy. Dedicated as dosing and metering pumps, they are versatile, reliable, and applicable to a wide range of applications.
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DWS offers a large range of API 675 pumps, with several technologies including zero leakage design. Our API 675 pumps have a broad range of features and options that make them perfect for any kind of application.
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