Filter Grid

The previous article stated that the main function of the filter grid is to filter out the effect of scattered rays on the film.
Today, I’d like to supplement the content of the filter grid
(1) The application of high purity lead in the filter grid provides high efficiency in the aspect of anti-scattering.
(2) The precise combination of the aluminum base and the aluminum bar makes the high-quality image possible.
(3) The smooth aluminum cover is coated with lead bars and enameled to protect the filter bars from heat and dust and to avoid maintenance for years.
Advantage:
(1) Variable size
From the standard 5 x 7 “to 14 x 51”, special sizes can also be customized, with the filter grid size one inch larger than the corresponding film size.
(2) Variable grid ratio
From 3:1 to 15:1, the grid ratio refers to the ratio of the height of the lead bars to the width of the clearance.
(3) Focal length range
From the standard short (26 “-32”) medium (34 “-44”) long (40 “-72”, 48 “-72” 60 “-72”) to infinity (parallel lines).
(4) High grid density
From 60 or 70 lines/talent, to high density (85 lines/inch), ultra-high density (103 lines/inch), invisible lines (105 lines/inch), and ultra-invisible lines (170 or 200 lines/inch).
Classification:
According to the structure:
1 convergence gate: each lead bar is inclined to the focus, that is, the lead bar extension line is concentrated at the focus (most used).
Parallel grid: each lead bar is parallel to each other in the vertical plane
3. Cross grid: it is composed of two parallel grids, and the direction of lead strips is 90° from each other
Arc grid: it is formed by overlapping the center outward with the same radius, tile sheet
According to the material of the filter grid, there are two forms:
1. Common filter grids — the internal compartments are made of non-metallic materials, such as wood chips, paper, plastics and other non-metallic low-density materials.
2. All-metal filter grid — its internal spacer is metal material: aluminum sheet.It has high strength and good moisture resistance.
Filling material: paper base, aluminum base, carbon base
Aluminium-based absorption of radiation is low and economical
The paper base is susceptible to moisture and is rarely used now
Carbon – based production process is troublesome, cost is high, but ray transmittance is good, imaging quality is good.
For example, the principle of the filter wire grid is: the use of tightly arranged lead strips to absorb scattered lines, so that the chest, abdomen, abdomen and other thick body position clarity improved
Grid density refers to the number of lead strips per unit distance.
The filling materials of the filter gate include paper base (the least used), aluminum base and carbon base. The cost of carbon gene is high, so the price is also high, but the transmittance is good and the imaging quality is good.
Divided by motor function, there are two forms:
1. Fix the filter grid
2. Vibrational filter grid: The filter grid with low grid density (28L/cm) can only be used as a mobile filter grid and is mainly used in power-frequency X-ray machines.
Newheek production of filter grid quality, price concessions, Welcome to consult!

Author：Lillian