Cylinder Safety Factor
Calculation data
| Quotation no. | 1410-0105 | Quotation date | 14-10-25 |
|---|---|---|---|
| Company name | For catalog | Site name | AAA |
| Quantity | 1 | Contact person | 홍길동 |
| dn@donam.co.kr | |||
| Design specifications | |
|---|---|
| Rated load | 3,000 kg x 2 = 6,000 kg |
| Car weight | 3,000 kg x 2 = 6,000 kg |
| Rod weight | 210 kg x 1 = 210 kg |
| Rope + sheave | 379 kg x 1 = 379 kg |
| Total load | Wt = 12,589 kg |
| Travel | (8,200 mm ÷ 2) + 250 mm = 4,350 mm |
| Required speed | 20 m/min |
| Roping method | 2:1 (indirect) |
| Application | Passenger · Freight ◀ · Car · Other 1 · Other 2 |
| Cylinder size | Ø195 mm x 4,350 x 1Cy | Tank (flow) size | B(335 ℓ) x 1Pu |
|---|---|---|---|
| Cylinder weight | 337 kg/unit | Tank weight |
Cylinder basic data
| Item | Outer diameter (cm) | Inner diameter (cm) | Material | Tensile strength (f: kg/cm²) | Tube/rod bottom plate data | ||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | Dimension | Symbol | Dimension | Thickness (cm) | Material | Tensile strength | |||
| Tube | Tb | 27.3 | Tb | 24.9 | STKM13 | 3800 | 20.0 | SS-400 | 4100 |
| Rod | Rd | 19.5 | Rd | 17.6 | STKM13 | 3800 | 20.0 | SS-400 | 4100 |
| Support point factor | n | 1 | Pump efficiency | % | 90 |
|---|---|---|---|---|---|
| Yield point | σ | 2200 kg/cm² | Motor efficiency | % | 80 |
1) Safety factor calculation (S)
| Item | Formula | Value | Calculation | |
|---|---|---|---|---|
| Pipe | Tube | (2.f.thickness:Tt) ÷ {(pressure: P ÷ Cy quantity) x inner diameter(Tb)} | 7.8 | (2 x 3800 x 1.2) ÷ {(47.2 ÷ 1) x 24.9} |
| Rod | [{(RD²) - (rd²)}.f] ÷ {2 x (pressure: P ÷ Cy quantity) x (RD²)} | 7.5 | [{(19.5²) − (17.6²)} x 3800] ÷ {2 x (47.2 ÷ 1) x (19.5²)} | |
| Bottom plate | Tube | {(4.f) ÷ pressure:P} x {Bt ÷ (tb²)} | 250.9 | {(4 x 4100) ÷ 42.2} x (20.0 ÷ 24.9)² |
| Rod | {(4.f) ÷ pressure:P} x {Bt ÷ (rd²)} | 502.1 | {(4 x 4100) ÷ 42.2} x (20.0 ÷ 17.6)² | |
2) Rod buckling strength calculation
| Item | Symbol | Formula | Value | Unit | Calculation |
|---|---|---|---|---|---|
| Rod wall cross-sectional area | Ao | {(outer diameter(RD) ÷ 2²) − (inner diameter(rd) ÷ 2²)} x π | 55.3 | cm² | {(19.5 ÷ 2²) − (17.6 ÷ 2²)} x π |
| Minimum second moment of area | I | [π x {(outer diameter: RD⁴) − (inner diameter: rd⁴)}] ÷ 64 | 2,386.3 | [3.14 x {(19.5⁴) − (17.6⁴)}] ÷ 64 | |
| Radius of gyration | Y | √(second moment of area(I) ÷ rod wall area: Ao) | 6.6 | cm | √2,386.3 ÷ 55.3 |
| Slenderness ratio | λ | (maximum free length: L) ÷ (radius of gyration: Y) | 66.2 | 435 ÷ 6.6 |
➔ According to the Gordon-Rankine table, slenderness ratio (λ) ≤ 85 x √support point factor(n) → [66.2 ≤ 85 (= 85 x √1)]
| Safety factor | S | {(π²) x E x rod wall area(A)} ÷ {(Wt − rod weight ÷ 2) x (λ²) ÷ Cy quantity} | 20.9 | {{(π²) x 2,100,000} x 55.3} ÷ {(12,589 − 379 ÷ 2) x (66.2²) ÷ 1} |
|---|
Unit selection data
| Item | Symbol | Formula | Value | Unit | Calculation |
|---|---|---|---|---|---|
| Rod cross-sectional area | A | {π x (rod outer diameter(RD) ÷ 2)²} x Cy quantity | 298.5 | cm² | {π x (9.8²)} x 1 |
| Actual delivery flow | Q | calculated flow = {A x V} ÷ {roping x 10} | 300.0 | ℓ/min | ← bar |
| Pressure | Pw | {(car weight + load) x roping + other(Wo)} ÷ A | 42.2 | kg/cm² | {(6000 x 2) + 589} ÷ 298.5 |
| Total pressure | Pt | pressure(Pw) + pressure loss | 47.2 | kg/cm² | 42.2 + 5.0 |
| Required power | Mp | {(flow(Q) x pressure(Pt)) ÷ 612} ÷ efficiency(%) | 28.9 | kw | {(300.0 x 47.2) ÷ 612} ÷ 80% |
| Actual speed | V | (flow(Q) x roping x 10) ÷ A | 20.1 | m/min | {(300.0 x 2 x 10) ÷ 298.5} |
Unit selection result ➞ 1 unit & 1 cylinder
| Type | Pump | Motor | Voltage/frequency | Control valve | FG | Tank type | Minimum required oil volume |
|---|---|---|---|---|---|---|---|
| 1 unit | 250 L x 1 | 29 kw x 1 | 380 V, 60 Hz | 1.5″ x 1 | #2 | B x 1 | 335 ℓ x 1 Cy |