Discussion on the safety of floor drain and suctio

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Talking about the safety of floor drains and suction valves

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1 drainage on the same floor

indoor riser drainage on the same floor is a novel design, construction and installation process. After the completion of the reinforced concrete floor, the flat and thin horizontal floor drains and pipes are directly connected to the riser in the leveling layer. The toilet adopts rear drainage, or the split water tank is hidden in the partition of the pipe gallery. In order to facilitate pipe maintenance, a waterproof access door is set in the shower room. In the master's bathroom, there is a sufficient and reasonable arrangement for the water seal of the bathtub drainage pipe. It is advisable to raise the bottom of the bathtub above the leveling layer. The height of the leveling layer is only 55mm higher than that of the traditional floor. It not only solves the problem that the dripping and clearing of the traditional drainage pipes through the building affect the environmental health of the neighbors, but also saves investment compared with the use of caisson buried pipes. In terms of equipment replacement and pipe maintenance, compared with the caisson buried pipe method, the former is light, while the latter is time-consuming and laborious

2 discussion with specifications

the difficulty of developing the same floor drainage is not technology, but traditional concepts. From article 4.5.9 of the recent code for design of building water supply and drainage (GB) (hereinafter referred to as the "new code"), we can realize that the development of new technologies will encounter many difficulties and obstacles. Article 41519 of the "new specification" stipulates that the water seal depth of the floor drain is formulated according to the provisions of foreign specifications. 50mm water seal depth is the basis for determining the vent pipe diameter and drain pipe diameter of gravity flow drainage system. In some areas, it is inappropriate to try to add suction valves to reduce the depth of water seals. First, the suction valve only balances the negative pressure, but cannot eliminate the positive pressure fluctuation. Second, the aging of the suction valve disc causes indoor environmental pollution after the loss of function. Third, reducing the water seal depth of the floor drain is bound to reduce the water seal volume, which is easy to evaporate and dry up. A little reading of the literature will realize that the suction valve can eliminate the negative pressure, and the siphon pumping loss is close to zero. The positive pressure does not need to be eliminated by the valve, but depends on the "multiplication" structural principle and uses the energy in the pipe to promote the increase of water seal. The aging problem of the suction valve disc is the most critical part of the technological breakthrough. Wear resistance, oil resistance, dense silicone rubber and anti-aging agent are used to improve the technical performance. The aging period is up to 8-10 years. It is easier to replace the bulb at home. It can be seen from the following calculation that the safety of bell jar type ground water leakage seal is worse than that of water seal protection type ground leakage with slight pumping loss under both dynamic and static conditions

3 calculation comparison

(1) dynamic calculation of water seal of bell type floor drain (see Figure 1)

known: static water seal depth h0=5cm, dynamic loss water seal h1=3cm

① evaporation area of outer ring water seal

f1=fa fb= 8=41.2cm2

where: fa=0.785 × 11.42=102cm2

Fb=0.785 × 8.82=60.8cm2

② water supply area of inner ring water seal

f2=fc fd=52 5=27.28cm2

where: fc=0.785 × 8.22=52.78cm2

Fd=0.785 × 5.72=25.5cm2

③ after the water seal is lost, you can copy or save it and take down the sample to calculate the recovery height

the water volume with the inner ring pumping height of 3cm

ω Inner =h1 × F2=3 × 27.28=81.84cm3

the water seal rises when the inner ring is reset

h3= ω Inner/(f2+f1) = 81.84/(27.28+41.2) =1.2cm

rising height of water seal h4=h2+h3=2+1.2=3.2cm

④ effective evaporation water available from floor drain

ω= H4(F1+F2)=3.2 × 68.48=219cm3

⑤ put ω Converted to allowable evaporation depth

h5= ω/F1=219/41.2=5.3cm

(2) water seal dynamic calculation of water seal multiplication protective floor drain (see Figure 2)

known: the static water seal depth h0=2.5cm, the guaranteed height of the water seal after dynamic pumping loss h ≥ 2.3cm

① the design inner diameter of the funnel hole d=3.9cm, the evaporation area of the water in the hole


② design water surface area of water storage weir:

f2=f1+2.5f1=12+30=42c the accuracy of tension machine is required to be plus or minus 1% (indication precision) m2

③ effective evaporation water available from floor drain:

ω= two point three × 42=96.6cm3

④ convert x into allowable evaporation depth:

h= ω/F1=96.6/12=8.05cm

(3) static calculation of water seal of bell type floor drain

① static water seal height:


② recharge water available for floor drain:

ω= 5 (f1+f2) =342.4cm3

③ convert x into allowable evaporation depth:

h= ω/F1=8.3cm

(4) water seal static calculation of water seal multiplication protective floor drain

① static water seal height:


② recharge water available for floor drain:

ω= H (f1+f2) =105cm3

③ convert x into allowable evaporation depth:

h= ω/F1=8.75cm

4 conclusion

the above calculation shows that the bell top floor drain has no advantage in terms of static or dynamic comparison. 14. Accuracy of strain control rate: rate <0.05% FS/s time lapse. Because the latter design takes low water seal as the guiding ideology, and specially uses the way of less evaporation loss and high compensation to achieve high performance. Setting the high-quality suction valve in a concealed place can better ensure its unique effect. The floor drain is protected by water seal, and the concept should be updated

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