Vacuum Disc Research Articles

Spine radiographs in patients with low-back pain. An epidemiological study in men.

A cohort of 321 men between the ages of eighteen and fifty-five was randomly selected from a group of 1221 men who had been surveyed by a questionnaire. They then had radiographs made of the lumbar spine. Of the 292 subjects fulfilling the criteria for inclusion in the study, ninety-six (32.9 per cent) had never had low-back pain, 134 (45.9 per cent) had had or were having moderate low-back pain, and sixty-two (21.2 per cent) had had or were having severe low-back pain. In the three groups there was a similar frequency of transitional vertebrae, Schmorl's nodes, the disc vacuum sign, narrowing of the disc space between the third and fourth lumbar and the fifth lumbar and first sacral vertebrae, and claw spurs. When there were traction spurs or disc-space narrowing, or both, between the fourth and fifth lumbar vertebrae, an increased incidence of severe low-back pain was evident. There also was a significant association of these two radiographic findings with symptoms (pain, weakness, and numbness) in the lower limbs. The measured lumbar lordosis, the length of the transverse process of the fourth lumbar vertebra, and the relationship between the fourth and fifth lumbar vertebral bodies with reference to the intercristal line had no association with the low-back pain. Increased lumbar lordosis had a significant association with decreased disc-space height and wedging deformity of the disc between the fourth and fifth lumbar vertebrae.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of plastics and glass-reinforced plastics in place of stainless steels and nonferrous metals in chemical plant

The South Donets branch of the Scientific-Research Institute for Chemical Plant Construction is in the process of designing vessels from composite materials based on glass-reinforced plastics (GRP). A tentative list of units and components of the filtration equipment is presented which may be fabricated from polymeric materials, e.g., filter plates in FPAKM and FPAB filter presses; plates and frames of frame filter presses; the drum, pan, and matrix of vacuum drum filters; the disks of vacuum disk filters, the filter plates of plate filters, the filter screen of VSF filters; the cartridges of cartridge filters; and the drainage units in FPAKM filter presses. Points out that research and test-construction studies are being contemplated on the development of units and components of cartridge, belt, and leaf filters from polymeric materials and further developments in perfecting structural units and components made from plastic.

Design throughputs in rotary disc vacuum filtration with incompressible cakes

New filtration rate equations are derived which take into account the sectioning of the disc, the reduction of the vacuum level to prevent cake cracking after emergence of the cake from the slurry and the variable hydrostatic head. The equations can be used to determine the cake thickness at any point on a disc segment after filtration. Calculations using the equations support the claims made by Wetzel [3] for an improved design of disc filter.

DU 250-3.75 disk vacuum filter

DU 250-3.75 disk vacuum filter

Disk vacuum filter with a thickening device

Disk vacuum filter with a thickening device

A new disc vacuum filter for coal slurries

A new disc vacuum filter for coal slurries

Inductance and internal resistance of vacuum disc switches: G N Aretov et al,Zh Tekh Fiz, 38 (6), June 1968, 1079–1084 ( in Russian).

Inductance and internal resistance of vacuum disc switches: G N Aretov et al,Zh Tekh Fiz, 38 (6), June 1968, 1079–1084 ( in Russian).

Glass-plastic sector of disc vacuum filter

Glass-plastic sector of disc vacuum filter

829. A suspended disc vacuum gauge: A R Beavitt et al, J sci instrum (J phys E), ser 2, 1 (1), 1968, 45–51.

829. A suspended disc vacuum gauge: A R Beavitt et al, J sci instrum (J phys E), ser 2, 1 (1), 1968, 45–51.

A suspended disk vacuum gauge

A wide range radiometer effect pressure gauge has been devised which gives a linear deflection with pressure over a theoretical range from 0·1 mtorr to less than 100 ptorr. The low pressure limit, set by photon pressure in radiometer effect gauges, has been extended by the utilization of specular reflection from the gauge surfaces. An expression has been derived for the deflection in absolute terms, and over a pressure range 0·4 μtorr to 0·1 mtorr an ion gauge has been found to give good agreement with the calculated pressure.

981. Time characteristics of vacuum disc switches: G N Aretov et al,Zh Tekh Fiz, 37 (1), Jan 1967, 131–138 ( in Russian)

981. Time characteristics of vacuum disc switches: G N Aretov et al,Zh Tekh Fiz, 37 (1), Jan 1967, 131–138 ( in Russian)

1589. A laboratory disk vacuum filter

1589. A laboratory disk vacuum filter

Laboratory disc vacuum filter

Laboratory disc vacuum filter

662. Sliding disc vacuum valves: Anon., Engineer, 213 (5538), 16 March 1962, 501.

662. Sliding disc vacuum valves: Anon., Engineer, 213 (5538), 16 March 1962, 501.