For an infinitely long rod, its axis is parallel to the magnetic field H, then N d =0; for an infinitely thin piece, vertically placed in the magnetic field H, then N d =1; for the ball N d = 1/3. Thus, the variation range of the demagnetization factor is 0 ≤ N d ≤ 1. Magnet demagnetization factor ore average 0.16. For finite size objects: For ferromagnetic and paramagnetic materials (X>0), the vector F→ m is consistent with the direction of the grad vector; the opposite is true for the diamagnetic material (x<0) direction. Equation (36) is the basic formula for calculating the specific magnetic force of a particle in a magnetic field of a magnetic separator. For a complete circular multi-pole magnetic circuit, the relationship between the magnetic induction intensity B→(Z) in the Z direction outside the surface of the magnetic pole and the residual magnetic induction intensity B r of the magnetic material can be expressed by the following formula: Where r 1 ———the inner radius of the pole ring; Generally, the cylindrical magnetic separator requires only a part of the cylindrical surface to require a magnetic field, and the angle (wrap angle) of this part is about 120 to 150 degrees. Generally, the magnetic system is arranged in the radial direction into several separately polarized positive and negative magnetic poles. Such a magnetic system varies greatly in the absolute value of the magnetic field near the surface of the cylinder, resulting in a harmful tangential force that degrades the performance of the magnetic separator. press fittings produces accorindg to park ,connex ,vigea and nibco,Approved watermark Press Fittings，press fittings，vigea press fittings，Nibco press fittings Taizhou Runde Company , https://www.zjbrassfittings.com
H O =H(1+N dX ) (32)
M= X H/(1+N dX )= Xb H (33)
Where X b ———The magnetic susceptibility of the object.
By X b , the magnetization of the object can be obtained directly from the external magnetic field.
Similarly, the magnetic permeability μ b of the object is: 
To illustrate the characteristics of magnetic separator, introducing a relative permeability μ o HgradH concept (i.e. the force acting on the object 3 kg of particles of 1 m / ratio of magnetic susceptibility X bs =) is useful. [next]
(III) Magnetic circuit The magnetic circuit of magnetic separator can be mainly divided into open magnetic circuit and closed magnetic circuit.
A Open Magnetic Circuit Figure 5 shows the typical structure of the open magnetic circuit of a permanent magnet cylinder magnetic separator.
r 2 ———the outer radius of the pole ring;
n———the number of polarization directions, only related to the polar angle φ B =-nφ0; n is a positive integer;
φ———Polarization angle.
When K (number of poles) = n + 2,