It is based on the combined knowledge and experience of seal manufacturers, engineering companies and end users. API is primarily intended for use in the petroleum, natural gas and chemical industries but is often referenced for other types of equipment and industries. By the late s, mechanical seals had been accepted as the preferred method for sealing rotating pumps for many years.
All of these standards were primarily pump standards and any references to seals were directed at how mechanical seals would interact with pumps. API is the API standard about centrifugal pumps and is primarily intended for use in the petroleum, natural gas and chemical industries. In the late s a group of refinery equipment engineers and managers began to compare sealing solutions in refinery applications. This group, led by V. A Task Force was formed in and the first meeting was held in January This Task Force was composed of fourteen members from various refineries, seal and pump manufacturers.
One interesting aspect of API is that it includes a strong set of defaults. That is, unless the user indicates otherwise, API makes default choices for specifics such as: . Some statements within API are normative, that is, required, whereas others are informative, that is, descriptive but not required. In particular, many of the illustrations are informative. This distinction has not always been apparent to the reader. This standard is designed to default to the equipment types most commonly supplied that have a high probability of meeting the objective of at least three years of uninterrupted service while complying with emissions regulations.
Although this mission statement no longer appears in the standard, it remains the basic principle driving the work of the API Task Force and its relevance remains the same for the 4th Edition as it did for the 1st.
In addition to providing requirements for mechanical seals, the 1st Edition of API also provided a guide on how to select the correct seal for a number of common refinery applications.
In order to provide this seal selection guide, it was necessary to categorize applications into a number of services: .
API Piping Plans
It was also necessary to categorize the many different type seals that were used in these services. Three seal types were designated: . As a result, there was some confusion on how multiple seals were designated.
The task force decided to use a more descriptive designation and chose to define dual seal arrangements. A dual seal would be two sets of sealing faces used in the same seal chamber. The fluid between these two sets of sealing faces could be either pressurized or unpressurized. Three standard arrangements were defined: . After having defined the services, seal types, and seal arrangements, a series of flowcharts were created to help in selecting a seal type, special materials or design requirements, and supporting piping plans.
API seals were to have a high probability of three years of reliable service. In order to prove this, seal performance testing on process fluids under representative pressures and temperatures was required.Log In.
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Are you an Engineering professional? Join Eng-Tips Forums! Join Us! By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. As a piping estimator, I'm always interested in the purpose of equipment and general design in water and wastewater treatment plants. So this question is solely for my curiosity. What is the purpose of a seal water line going into a pump casing?
Does it fill some sort of diaphragm that seals in water? Does it ensure that the impeller cavity is completely full of water, so that air won't be trapped at start up? Thanks for your time. Its purpose is basically to supply water to the shaft sealing system which will be either a mechanical seal or packing gland which require lubrication or cooling. To expand on the point already made, the seal water is generally used to cool the seal or to displace the pump product which may have poor properties for use in a mechanical seal or packing.
If the product is abrasive, for example, a cleaner stream of seal water might be used to fill the seal chamber so that the mechanical seal is running on this clean water rather than the abrasive process water. The water introduced as seal water usually leaks externally for packing or leaks internally into the product stream.
So, for most cases, the flush water has to be compatible with the product stream. The cost of this flush also needs to be taken into account. Downgrading high-value ,clean water into a dirty stream can be very expensive. You could search for information related to an API Plan 32 seal flush system if you want more details.
Johnny Pellin. A little more into hw it works is that the liquid comes from the high pressure part of the casing caused by centrifugal energy and into the lower pressure seal area thus unsuring a constant flow of liquid to flush or keep debris moving if present in the liquid.
On larger pumps there are sometines orifice plates to ensure the pump is kept efficient and simply not recirculating within itself. There is also new 'bell mouthed stuffing box' technology which eliminates the need as much for the flushing, and recirculates internally - clearly tappings and small pipework has smaller material thicknesses and so if priduct is corrosive, leakage can occur.
Thank you all for your answers, your time and insight is appreciated.We know that you need reliable seal performance to maximize process efficiencies while meeting production targets and constantly evolving, stringent operational requirements. Our expert engineers have designed a range of fluid control systems that create the optimal operating environment to enable the dependable performance you expect from a John Crane seal.
No matter what the process fluid, from liquids to gases, cryogenic to boiling and abrasive to the purest finished product, our range of barrier fluid reservoirs, heat exchangers, abrasive separators and pump seal gas control panels support the most complete spectrum of industrial processes. Don't see what you're looking for?
Used to detect and monitor leakage of the inboard seal, these seal support systems can detect liquid leakage API Plans Used to provide a clean, regulated gas supply to a dual unpressurized seal arrangement where the containment seal is dry These reservoir-based seal support systems are designed for both API Plan 52 and 53A applications to support unpressurized and pressurized Portable units enable refilling of a seal reservoir or barrier fluid circuit while the system is pressurized and in operation Plant seal water filtration system, maintaining clean water supply to improve the reliability mechanical seals and gland packing and also SafeJet is an automatic seal water filter.
PG 72 Gas Panels Used to provide a clean, regulated gas supply to a dual unpressurized seal arrangement where the containment seal is dry Safeclean Seal Water Filter System Plant seal water filtration system, maintaining clean water supply to improve the reliability mechanical seals and gland packing and also Safejet Compact in-line seal water filter SafeJet is an automatic seal water filter.
SmartFlow Intelligent Seal Water Control System SmartFlow intelligent seal water control system uses seal water only when the mechanical seal truly requires cooling. Hundreds of engineering experts. Over global locations. Connect Now.Tired of watching your money spiral down the drain from mechanical seal repair or replacement? A few simple principles can guide you to the best seal flush plan for your installed mechanical sealallowing the seal to operate in an environment that generates optimal seal life yet minimizes costs from water usage and product dilution.
Can only be used if the pumped fluid is clean, does not exceed the temperature limits of the seal, is compatible with the seal components, and is in no danger of vaporizing or solidifying when exposed to the additional friction heat generated by the seal. If this plan is used, a tapered or self-venting seal chamber is highly recommended.
This method is used when the pumped fluid is clean, does not exceed the temperature limits of the seal, and is compatible with the seal components. Normally, this method consists of piping run from the pump discharge to the flush connection on the seal gland, providing flow from the pump, past the seal, and back into the pump through the seal chamber throat.
It can also be piped from the flush connection on the seal gland back to the pump suction, which would result in the flow going the opposite direction and can have the added benefit of lowering the operating pressure at the seal. If warranted, accessories such as a heat exchanger or pressure reducing orifice can be installed in the piping. A bypass flush provides circulation flow past the seal faces to carry away seal generated heat, so the seal operating temperature will stabilize at the temperature of the pumped fluid.
This method is simple, reliable, and inexpensive. It does not result in product dilution and is the preferred seal flush method unless there is a specific reason not to use it. The external flush method is used when it's desirable to isolate the seal from the pumped fluid. However, if you do not have a suitable flushing liquid available or if diluting the pumped fluid with the flushing liquid is unacceptable, this is not an optimal solution.
This method consists of a minimal flow of a clean, relatively cool liquid usually water from an external source injected into the seal gland flush connection at a pressure higher than the pump seal chamber pressure.
Cooling Water Requirements For Api 610 Pumps
The external flushing liquid flows past the seal and into the pump, mixing with the pumped fluid. Usually a flushing liquid pressure of about psi above the pump seal chamber pressure is sufficient.
Flow rates of about 0. A restriction bushing or lip seal can be installed at the seal chamber throat to minimize the flush water flow. A control valve, gauge, and flow meter should be installed in the flushing liquid supply line to provide the control functions necessary to set and monitor the flushing liquid supply, with the flow meter being the most important so that a positive flow of flushing liquid into the pump can be confirmed.
It can only be used with a seal that has special circulating features. The seal must be equipped with a device that generates some circulation flow basically a small impeller and piping in and out of the seal chamber through a heat exchanger. If you are considering an induced closed loop circulation system contact your local seal supplier to come up with the best system design.
Do you have general questions about mechanical seals or are you wondering which seal flush piping plan is best for your situation?Jump to content.
Low Flow in Pipes - posted in Ankur's blog. Posted 15 April - AM. Posted 16 April - AM.
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Featured File Vertical Tank Selection. This topic has been archived. This means that you cannot reply to this topic. Hope some learned members can shed some light on this. Regards, Ankur. But I need some kind of numbers for the cooling water flow for each cooling plan. I would just call up the local vendors and give them the basis pump details and I'm sure they will throw more light on this issue.
Hope this helps. Dear Qalander, Thanks for the insight. If cooling water is required for your pumps I would suspect that even in basic data sheets the required information would be present.
When consulted, my senior told me use a 10GPM per pump as a "rough" cooling requirement. The vendor came back with his info after 2 weeks and so I was saved from some sleepless nights.
I do not want to "advocate" using this figure, but, it turned out to be a fair estimate as the cooling need for pumps did not exceed this figure in my case. Again, would say that just sharing my experience, not "advocating" to use this figure.
Sign In Need an account? Register now! I've forgotten my password. Remember me This is not recommended for shared computers.Although these standards may be referred to alongside API, they are not otherwise related, and although some of these standards overlap, each one is generally focused on a different sector.
API standards include design criteria for a wide range of equipment and components. Even though there is no overall rule or law that API standards must be adhered to many pumps and equipment are built to no standard at all the API standard is often referred to in pumping systems when the highest quality is needed. API is the API standard relating specifically to centrifugal pumps and centrifugal pumping systems. It provides design criteria for the design of the actual centrifugal pump, as well as how the centrifugal pump is to be tested, and what type of base it is to be mounted on.
Within the API Centrifugal Pump Standard, there are various configuration codes for different types of centrifugal pumps.
These are called out by a set of two letters followed by a single number. The number is used to differentiate more detailed configuration options within each section. Below are simple definitions for each API pump type.
The pump is mounted to a baseplate and driven via a flexible coupler. The API OH2 is a horizontal, centerline mounted, single stage, overhung pump with end suction and a single bearing housing. The single bearing housing helps absorb the forces imposed on the pump shaft and maintain the position of the rotor during pump operation.
The bearing housing is integral with the pump to help absorb the loads imposed on the pump, and the motor is generally mounted on a support that is also integral with the pump. The pump and motor are coupled with a flexible shaft coupling. The API OH4 pump is a vertical inline, single stage, overhung pump with a rigid coupling on the pump and motor shafts.
The C-face of the motor is mounted directly to the pump housing.
The API OH5 pump is a vertical inline, single stage, overhung pump that is close coupled with the motor. In the close coupled design, the pump impeller is mounted directly to the motor shaft the motor shaft is designed to be extra-longand the C-face of the motor is mounted directly to the pump housing. The API OH6 is a horizontal or vertical, single stage, overhung, high speed pump that has an integral gearbox mounted to the pump housing. The gearbox is driven by the motor with a flexible coupling, and the pump impeller is mounted directly to the high speed shaft of the gearbox.
The BB1 is an axially split, one or two stage pump with bearings on both ends of the rotating assembly. The pump is mounted to a baseplate and driven by a motor via a flexible coupling. The BB2 is a radially split, one or two stage pump with bearings on both ends of the rotating assembly. The BB3 is an axially split, multistage pump with bearings on both ends of the rotating assembly.
The BB4 is a radially split, multistage pump with bearings on both ends of the rotating assembly. The BB5 is a radially split, multistage pump with bearings on both ends of the rotating assembly. Because of its round design, the BB5 pump can be made to handle very high pressures.Pressure vessels are tested for leaks with a hydrostatic pressure test.
The test involves filling the vessel with a liquid, usually water, and pressurizing it to the specified test pressure. That is, suppose a certain vessel has an MAWP of psig; it would be hydrostatically tested at psig. Of course, there are other details such as the duration of the test, variations based on operating temperature, etc. But basically, the hydrostatic test pressure has been 1. However, it has not always been that way and may be about to change.
In Section Adjustments must be made based on the allowable working stress of the material based on operating temperature. The hydrostatic test duration is 30 minutes without leaking. Apparently, in the future, the hydrostatic test pressure ratio will be changed from 1.
This will be applied to both pumps and piping. The same multiplier will probably be used for API reservoirs such as are used with Piping Plan 52 and The pertinent 4th Edition clauses for reservoirs now read:.
Unless otherwise specified or required by local code, the reservoir shall be designed, fabricated, and inspected in accordance with ISO or ASME B With this wording, the default is a pipe based reservoir but an ASME certified reservoir is an option.
This inspector also witnesses the ASME hydrostatic test which, apparently, is now 1. This means that U stamped vessels cannot be manufactured in advance; that is, the U stamped vessel is customized for a particular service, has a serial number and therefore cannot be a stocked item.
The fabricator undergoes an ASME inspection every three years. It should be noted that the mechanical seal is not considered to be part of the pump pressure vessel and therefore does not fall under pressure vessel rules. Seal manufacturers have several pressure ratings for their products.