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What is the price difference for regulating valves? How to compare the valve body, internal components, actuator and acceptance scope
There is a significant difference in the quotes for the two regulating valves, so don't just compare the model and diameter for now. The valve body may be the same, but the internal capacity, contact material, actuator, locator, testing, and delivery documents may still differ. Let the supplier list the configurations and deviations item by item according to the same set of operating conditions, in order to distinguish whether the price difference comes from functional differences, material differences, or omissions in the quotation range.
First, write 'same operating condition' at the top of the quotation sheet
For example, in the steam regulation project of a heat exchanger, one company selects valves based on daily steam consumption, while the other includes the start-up peak in their calculations, resulting in different diameters or internal components. Put the minimum, normal, maximum flow rates and their respective pressure and temperature on the same table, and request that the quotation use this set of data instead of treating different calculation assumptions as high or low performance.
The maximum closing pressure difference and allowable leakage for the shutdown task column. Easy to operate during normal adjustment, but it does not mean that the parking state can be reliably turned off; The quotation should indicate the corresponding relationship between the internal components, driving capabilities, and shutdown requirements.
Comparing internal components, we cannot just look at how much DN is written on the valve body
The same diameter can be configured with different rated flow coefficients, valve core characteristics, and throttling structures. A solution with a larger capacity may work at a smaller opening, while a solution with a smaller capacity may not be able to cover the peak. Having the solution provide calculation results and estimated work opening is more valuable than having an additional adjective 'high-performance'.
When the medium contains particles, is prone to vaporization, or has a large pressure difference, compare the applicable instructions for the corresponding internal components. Just because a certain plan has a sleeve, it cannot be automatically assumed that it has noise reduction or anti cavitation capabilities; These functions need to correspond to specific structures and computational conditions.
The valve body material may be the same, but the complete liquid connection list may also be different
The quotation states' stainless steel valve 'without specifying the valve core, seat, stem, packing, and gasket. For projects with high requirements for corrosion or cleaning, these components should be listed separately. Shell material is not synonymous with a complete set of liquid receiving materials.
Simultaneously compare the gas supply conditions, fault targets, locator input and feedback, accessory quantity, and environmental adaptation of the executing mechanism. The price that only includes the bare valve cannot be directly subtracted from the price that includes the driver, positioner, and complete functional verification.
Include acceptance and delivery scope as part of the price
When the contract requires material traceability, sealing tests, or complete action records, the scope of documents and judgment conditions should be provided during the inquiry stage. Subsequent inspection, witnessing, or documentation work may change the delivery date and cost, and items not included cannot be considered as free default items.
The supplier can be requested to reply with four items: "including content, not including content, technical deviation, and delivery documents". Clarify incomparable projects first, and then evaluate the total procurement cost; Do not use self guessing configurations to make up for a low price quote.
Bring this information when inquiring or comparing proposals
| project | What needs to be expressed |
|---|---|
| Fundamentals of Calculation | Three sets of flow rates and corresponding pressure and temperature are consistent |
| Key Configuration | Valve body, internal components, drive, locator sub items |
| Experimental documents | List of conditions, projects, and delivery scope |
| Business comparison | Evaluate deviations and excluded items together |
Common customer questions
Why can there still be a significant price difference when both companies report the same model?
The model often does not express all the internal components and accessories. Compare the capacity, complete materials, drive gas supply, locator function, and test documents to confirm if the supply scope is consistent before comparing prices.
Can I get a quote that can be directly replaced by sending only the original valve nameplate?
The nameplate is the starting point, and it also needs to indicate the actual working conditions, connection dimensions, and modification requirements. The original equipment may have had its internal components or accessories replaced; The replacement plan should address current needs, rather than just copying an old model.
There is no locator in the quotation, can I add one myself later?
It is necessary to first confirm the matching and control interface between the valve, actuator, and locator. Separate procurement is not impossible, but the entire itinerary, output capacity, fault response, and verification responsibilities should be clearly stated before ordering.
Related products:Single-seat pneumatic control valve See similar schemesControl valveWhen discussing specific supply, please provide the corresponding working conditions and functional requirements in the text together.
Extended reading:How to choose between single seat regulating valve and sleeve regulating valve?。
Technical reference:Emerson/Fisher Control Valve ManualReference materials are used for corresponding structures or engineering principles, and specific finished products are evaluated based on their corresponding configurations and rated conditions.
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