Mechanical seals

Mechanical seal for the pump

It is possible to increase the tightness of the pump with the help of a special product - a mechanical seal. This small product plays an important role by creating an additional layer in the contact of two surfaces to level the flow of different, sometimes very expensive or toxic liquids. Usually, the mechanical seal for the pump consists of two main parts. One of them is movable and is attached to the shaft. The other is completely stationary and is attached to the pump housing. Since the device operates under constant pressure conditions, the mechanical seal is considered the most vulnerable point in the entire pump design.

Structure of the mechanical seal for the pump

The standard mechanical seal for the pump has its own clear structure, which fully fulfills the tasks assigned to it with minimal use of additional substances for lubrication.

Delving into a more detailed structure, it is worth saying that the mechanical seal consists of nine main structural parts. The first is the mounting bolt, which serves to secure the product to the shaft. Next are the elastomeric seal, the pin responsible for transmitting the shaft rotation to the movable ring, the movable and fixed ring. The device also consists of:

  • The rear wall of the pump housing;
  • A pin that serves to prevent the rotation of a fixed ring;
  • Water pump shaft;
  • Springs to increase the tightness of the seal rings.

Due to such a competent structure, the product is able not to let the pumped liquid into the environment in cases of use in dry pumps and in electric motors in cases of use in submersible pumps. For more reliable protection against leaks, which in the future cause a lot of problems, sometimes you can use two mechanical seals on one shaft. However, in such cases, it is necessary to use a coolant. Water is not suitable in this case, because it can cause a short circuit.

Materials for the manufacture of mechanical seals.

The materials for the manufacture of seals for the pump depend on what purpose the further product will fulfill. Formally, based on the characteristics of the pumped liquid, temperature and pressure, the main production material is also selected. Relatively, they all fall into two categories: soft and hard. Depending on the tasks that are put on the end seal for the pump, they are made of:

  • Silicon Carbide;
  • Aluminum Oxide;
  • Tungsten Carbide;
  • Graphite impregnated with metals or synthetic resins.

Rubber, nitrile and viton are often used as secondary seals for pumps.

How does the mechanical seal for the pump work?

The seal is based on a fixed and movable ring. One of the rings moves due to the elastic part. It can be a spring, bellows or a special membrane. This element in combination with a pressure sleeve and a movable seal ring for the pump form a whole movable block or a preload unit. As a result, the rings provide the tightest possible contact of the end surfaces due to the movable and non-movable ring and the pressure of the medium.

Advantages of using mechanical seals for the pump

The main and most significant advantage that the use of a special suitable mechanical seal for the pump has is considered to increase the service life of the pumping station. In addition, the use of this part minimizes leaks, reduces the maintenance costs of the product, allows the pump to be loaded with high pressures without loss of system performance, and also opens up the possibility of using the pump in an aggressive working environment.

Conditions for the necessary replacement of the mechanical seal for the pump

According to statistics, it is believed that the mechanical seal is one of the fastest wearing parts in the pump. There are a number of reasons for this, such as constant pressure, friction, etc. therefore, there are a number of breakdowns that signal the immediate replacement of the mechanical seal in order to prevent the failure of the entire pump system. The most popular of them is the usual wear of the part. It occurs after prolonged operation of the device without proper maintenance. This is quite a common process that sooner or later will overtake any detail in the system. At the same time, it can be slightly delayed. To do this, it is enough to regularly check many factors. For example, the surface temperature in the area of the mechanical seal, the presence of abrasive inclusions or other deformations and cracks.

The next reason that can quickly disable the mechanical seal is the incorrect selection of the product model. In cases where the specialist has not previously analyzed the working environment, the type of liquid and other factors affecting the characteristics of the desired type of seal or the material at the heart of the manufacture, the wear process of the seal increases proportionally. At the same time, the service life is reduced several times, and therefore it is necessary to take special care to choose the right part for the pump. It is best to consult professionals in this field who have sufficient experience and knowledge.

In addition, in order for the mechanical seal to work without breakage, it is necessary to prevent the use of the pump during dry running. Only the correct installation of the pump automation, as well as the regulated and regular air discharge in the pumping part of the system will increase the level of wear resistance of the entire station.

It is also recommended to make the correct installation of the mechanical seal, since errors during this process are also an extremely popular cause of breakdowns not only of the part itself, but also of the entire pump system.

Features of marking of mechanical seals for the pump.

There are many popular manufacturers of pumps and mechanical seals for them. For example, companies: ebara, emu, flygt, fristam, gea tuchenhagen, goetze, grundfos, gücüm, haigh, hidrostal, hilge, inbeat, inox, nissin, packo, pasco, pedrollo, pentax, pompetravaini, pumpex, robushi, saer, salmson, speroni, sulzer, tsurumi. Each of them adheres to certain standards for marking end seals for the pump, which allow specialists to navigate during installation or maintenance of the device. Thus, the risks of breaking the pump by mistake or lowering further service life are eliminated.

So, for example, Lowara pumps require mechanical seals of the standard R-BT-FN, R-LW, R-LWR, R-MG12, etc.For pumps manufactured by Wilo, the seals of R-MG1, R-TSWE, R-H7N, R-156 are suitable. In any case, almost all pump manufacturers use mechanical seals of their own production or companies that are partners and specialize in the manufacture of parts for specific products.

Choice of mechanical seal for pumps

Since this part has many types and nuances of execution that directly affect the tasks performed by the product, it is quite difficult to independently choose a suitable mechanical seal for the pump. It is necessary to take into account many details that directly affect not only the performance of a separate area of the pumping station, but also the functioning of the entire system. Therefore, be sure to consult a specialist before ordering a mechanical seal for pumps.

There is a sufficient amount of information freely available, as well as tables of analogs of products for a more detailed study. However, in any case, a profile employee will help you pick up the part more quickly and clearly. He will analyze the working area, find out all the information about the properties of the liquid, pressure, temperature and other factors that affect the choice of the product and only then make his offer. Also, the specialist will determine the type of balancing and take into account the pump model so that the operating conditions of each part are as suitable as possible.