How to determine the seal form

I use the seal in the form of existing products are: packing, mechanical seals and sealing three forms of power.
1, packing:
Advantages: simple, cheap, easy maintenance; Disadvantages: leakage volume, pressure for a liquid seal, the number of leak points will appear. Our company is only in the volatile liquid medium or horizontal pump seal pump with non-critical condition, but also as a combination dynamic seal and secondary seal after stopping use.
2, mechanical seal:
Advantages: good sealing effect, leakage, long life; Disadvantages: expensive.
Mechanical seal pumps, as the company forms the main seal, basically all the products in my company to use for different conditions, can form different combinations.
With different washing programs, sealed in the back of the column we will discuss in detail. Our company is production for the mechanical seal has reached domestic leading level, the companys third-generation
Set-like mechanical seals are also fully meet the API682 standard.
3, the dynamic seal:
Advantages: reliable, easy maintenance, ability to adapt to working conditions; drawback: the need for auxiliary parking seal.
I generally dynamic sealing applications in the transportation of solid particles more media, and LZ vertical pump and other products.