Mechanical seals have a role in protecting the environment against contamination and making machinery run more efficiently, along with contributing to general health and safety. The key role of mechanical seals is to prevent fluids like water or oil from leaking into the area surrounding a piece of mechanical equipment.
Mechanical seals form a critical part of any mechanical operation involving fluid movement through rotational shafts, such as in the case of pumps. These seals ensure that the fluid does not leak out of a closed system and contaminants do not enter the system. In pumping applications, mechanical seals are placed at the point of entry or exit of a rotating shaft, preventing the pressurized fluid from escaping the pump housing and withstanding the friction generated from the shaft rotations.
Read on to learn how mechanical seals work and explore some popular use cases of seals in pump applications.
Centrifugal pumps are one of the most extensively used pumps in municipal and complex industrial applications. However, a proper sealing arrangement is imperative for these pumps to prevent fluid leakage and protect the pump’s inside from contaminants in the atmosphere. Mechanical seals are preferred for sealing the pump as they require less maintenance and are much more durable than packing seals.
Parallel pumping is a process that uses two or more pumps connected in parallel to control the fluid flow or use an additional pump(s) as an emergency backup. This type of pump configuration is common in wastewater plants and domestic water supply systems, where the flow rate gets distributed across the pumps connected in parallel while the pressure head remains constant.
Unlike modern wells, in the early days, wells commonly had a well pit and wellhead or union fitting that would connect the drop pipe to the supply fitting. The purpose of a well pit is to prevent water supply lines from freezing in regions with a colder climate, with the added advantage of allowing easy access to the technician for routine maintenance.
However, when covered with an access cover, these pits can deteriorate over time, becoming a trap for animals or small children. A tight-fitting access cover can also trap underground gases, making it a dangerous place to work. It is also possible that the concrete wall casing of the well pit can start cracking and disintegrating eventually, allowing surface water to seep into the pit and consequently contaminate it.
Mechanical seals are an integral part of machines that deal with hydraulics, pumps being an excellent example. Since there are different types of seals available, however, choosing the one that would work best for your pump can get tricky.
A pump casing is an outer shell of a pump meant to seal off internal components from the outside atmosphere while maintaining desired fluid pressure and preventing leakage. There are different casing constructions depending on the pump type, and each serves a distinct function.
With so many choices available for industrial pumps, the selection process often comes down to carefully evaluating the needs of the industry and choosing a pump that will be efficient and reliable in a specific application.
The case is no different when selecting sliding vane and rotary gear pumps. While both are types of positive displacement pumps, there are nuances that make one or the other better suited for a particular application.
Efficiency is an essential factor that influences pump selection. Wire-to-water efficiency is often a critical parameter when selecting a pump, especially when the pump needs to operate in an industrial environment. In large-scale industrial applications, even a difference of 10% in efficiency can significantly impact overall operating costs in a year.
In industrial engineering, friction can be helpful in some areas while it can severely affect performance in others. In pumps, friction serves the latter purpose. When two surfaces slide across each other, there acts a resistive force called friction. This resistive force slows down the movement between the parts and expends energy in the form of heat or sound.
