Muffler pump-related matters
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MVR vapor compressors are being used more and more in China. These compressors have a simple design; they typically come equipped with shaft seal pumps, without a high-level oil tank or an emergency oil pump. I would like to ask the following: 1. When the unit stops operating and the low-voltage power is cut off, can the unit safely reduce its speed to zero? 2. What are the common considerations for selecting shaft-mounted pumps? Please discuss this issue.
In such cases, when using a shaft-mounted pump, it is necessary to install a high-level oil tank or an emergency oil pump; otherwise, the safety risk is high.
This post was last edited by CHANGBAISHI on 2020-6-5 08:12. This should be a very common and well-established thing. As long as the oil quality is kept clean on a regular basis, it is safe and reliable. Eccentric gear pumps are also being used these days. These are all included with the equipment from the manufacturer, so there’s no need to select them separately, right? There is also information regarding the fuel supply during the safe idle process: as the engine speed decreases, the fuel supply pressure also gradually decreases, which is sufficient to meet the fuel requirements during the idle phase. Different from external oil pumps. I’m not sure if it’s due to design requirements or something else. For reference.
If the fuel supply system can be set up independently, a separate station can be constructed; there is no need for a shaft-mounted pump, which simplifies things
1. Almost all large pumps are equipped with shaft-mounted pumps; when the rotation speed decreases, both the flow rate and pressure drop, and the shaft-mounted pump can still meet the machine’s oil demand thanks to its rotational inertia. 2. For shaft-mounted pumps, the common brands are IMO and NVC. 3. The shaft-mounted pump can be a gear pump, an eccentric pump, or a screw pump. 4. Screw pumps are generally mounted on the low-speed shaft of the gearbox. 5. Be sure to set up the priming line for the shaft-mounted pump; although positive-displacement pumps have a certain degree of self-priming capability, it is often insufficient. 6. Shaft-mounted pumps are considered a type of wear-prone equipment.
There are indeed certain issues with shaft head pumps; in our facility, we have encountered a failure where one of the shaft head pumps in the reciprocating machine stopped operating due to the sudden breakage of the coupling bolts during operation (the oil pressure could not be established in time after the auxiliary oil pump started working). At present, we can only shut down the machine at regular intervals to check the wear of the bolts on the coupling of the shaft head pump.
Are your reciprocating machines imported or domestically produced? No high-level fuel tank?
In the later stage of idle rotation, the shaft-mounted pump no longer has much power
For domestic models, there is only one shaft-mounted pump and one auxiliary oil pump.