Abstract of RIIS Report ( SH-1956-1 )

National Institute of Occupational Safety and Health, Japan

Pressure Effect on the Explosion Limits of Coal Gas, Producer Gas and these Mixtures

SH-1956-1-1

Noboru Taguchi, Michio Naito, Kogaku Komamiya, Akio Horiuchi

: The purpose of this experiment is to conduce to the safety problem of the gas industry, by measuring the explosion limits of the city gas of which heat content is prescribed as 3600 Cal. under the pressure of 5 atms.
    For this object, the measurements were performed on the upper and lower explosion limits of coal gas, producer gas and these mixtures under the atmospheric pressure by using the electric sparks for ignition, and on the upper limits of the preceding gases under the pressure between 0 and 10 atms. gauge by using the heater ignition plug.
    The results of the measurements were concluded as follows,
  (1) The pressure effect on the upper explosion limit of coal gas is remarkable, because the upper explosion limit becomes 52 percent by volume under 10 atms. , although it is 32 percent by volume under 0 atm. gauge.
    But there is no pressure effect on the upper explosion limit of producer gas. Therefore, while there are many variation of the city gas of 3600 cal. heat content by changing the mixture ratio of coal gas, producer gas and air, the more the producer gas content is, the more the safety degree of the gas becomes under the high pressure.
  (2) The single city gas under the pressure of 5 atms. gauge cannot explode unless the addition of air, that is to say, it is out of the explosion range.

Studies on the Static Properties of Chain in Various Forms (2nd Report)

SH-1956-1-2

Gisei Mori, Kozen Hirai

: In order to determine the suitable size and form of the chain to couple trollies on the earth work and settle the safety practice of such a chain, both dynamic and static loading tests of the chain have been done. This report is based on the static loading tests of the chain of various forms in a same diameter of material.
    From these tests following results were obtained.
  a. The breaking load of chain is independent on its form and expressed as the following formula.
    P _u = 1.46·σ_u·d ² ,
  ,where P _u : the breaking load, σ_u : the tensile strength of material and d : the diameter of material.
  b. The yielding load of chain depends upon the both width and length of a link. When let x and y be such parameters that.
    l ₁ = (2x + 1 )·d
    l ₂ = (2x + 2y + 1)·d
    ,where l ₁ : the width of a link and l ₂ : the length of a link, the experimental expressions concerned to the yielding load P e are given as follows,
    P _e = Σ_e·σ_u·d ²
    and 1 / Σ_e = 16.797 - 21.738 x + 8.288 x ² + 0.186 xy ,
    ,where Σ_e : the coefficient concerned to the form of chain.
  c. The tenacity and the plasticity are preferable natures to the strength for the material of chain.
  d. The chain should be properly annealed after welding.
  e. The elastic elongation of a link depends upon x and y , and is expressed as follows.
    δ = Δ·P / d
    Δ = -13.066 + 13.585 x + 1.549 √( x )·y ,
    ,where δ: the elastic elongation (in cm) by P kg of load, and Δ: the coefficient concerned to the form of chain (in cm² /10⁶ kg).
  f. The permanent elongation of a link depends upon not y but only x , and the increase of a load P is linearly concerned to the corresponding increase of a permanent elongation δ as follows ;
    δ = ( P - P _e ) /μ(π - 2 )·δ_u·d and μ = 16.832 - 16.716 x ₀ + 4.355 x ₀ ² ,
    .where P _e : the yielding load of chain, μ : the coefficient concerned to the form of chain and x ₀ : the initial value of x.
    But expressions described hitherto are available when 1.2 ≤ x ≤ 2.0 and 0 ≤ y ≤ 1.5.
( CONTINUED )

On the Strength of Safty Belt Used the Work of the Pole

SH-1956-1-3

Tadashi Andou

: Important problem for safety belt has two subjects.
    One is strength of belt, rope and metal connecter and the other is how much shock the worker suffered by safety belt when he fall from top of the pole.
    Testing breaking strength of safety belts for static and dynamic loading and shock load which suffered human body was measured in the case of falling from the top of the pole.
    Safety belt is seldom danger to human lives in the case of falling from the top of the pole because of it limits to the length of rope.
    Breaking strength of tested safety belts were min. 1180 kg.

JNIOSH

Abstract of RIIS Report ( SH-1956-1 )

National Institute of Occupational Safety and Health, Japan

Pressure Effect on the Explosion Limits of Coal Gas, Producer Gas and these Mixtures

Studies on the Static Properties of Chain in Various Forms (2nd Report)

On the Strength of Safty Belt Used the Work of the Pole

Other Publications