DE10251149A1 - Fire smoke disperser for building has blower to generate overpressure and pressure regulated flaps to control airflow around building - Google Patents

Abstract

The fire smoke disperser has a by-pass flow generated around a building by an axial ventilator (2) using flaps (3.1) which are self closing and which open under a predetermined overpressure in the escape path. Compression springs keep the flaps closed until a set overpressure to provide an independent self regulating action. An Independent claim is also included for a method of keeping building escape routes smoke free using the ventilator system.

Description

The invention relates to a method and an apparatus for the Keeping escape and rescue routes smoke-free, taking into account permissible air pressure differences in adjacent corridors and Stairwells with an overpressure system.

The smoke-free keeping of necessary stairwells is an important one Prerequisite to evacuation of people and an extinguishing attack to enable the fire department. Stairwells and corridors are not Fire spaces. On the other hand, possible fire spaces are provided by the adjacent ones Usage units such as apartments, offices and the like. A mechanical Smoke extraction always creates a negative pressure in the exposed room. This can cause fire smoke from the usage units into the Stairway or the hallway sucked and the escape route becomes impassable. When using natural smoke extraction via smoke and heat exhaust, the grows Danger of the system becoming ineffective with cooling smoke. The Escape and rescue routes should therefore always be treated in Connect to a supply air fan to create an escape route To achieve overpressure compared to the unit of use and thus that Prevent smoke from entering the escape route.

In the event of a fire, the pressure difference on adjacent standard doors of about 2 m ² area must not exceed an atmospheric pressure of 50 Pa, since the maximum permitted door opening force is 100 N. Otherwise there is a risk that the door will no longer be able to be opened by slender or disabled people in the event of a fire.

A fundamental distinction must be made between smoke protection pressure systems Prevention of smoke entry and flushing systems. During printing plants have the task of completely preventing smoke from entering Dilute and remove the flue gas that has penetrated the flushing system.

In the following, essentially only pressure systems are considered. The facility must have a controlled overpressure in the emergency exit in case generate closed doors. The overpressure can cause smoke to enter prevent as long as all doors are closed. If a door opens, it is done pressure equalization in less than a second because the Pressure drop propagates at the speed of sound. At this moment it applies ensure that the open door cross section is adequate Speed is flowed through. Depending on whether there is a hallway, a lock or connects the unit of use, this is the required speed between 0.75 and 2 m / s. To flow through the open doors it is necessary to ensure that there are opportunities to escape from the Units of use are available.

The requirement for the overpressure system is that it is in less than one Second of the volume flow, which only covers the leakage is required to switch to the rated flow rate to achieve sufficient speeds in the open door.

The following applies to the design:
According to the model high-rise directive applicable in Germany, the volume flow for the door flow must be set according to the following equation:
V = k × w × h 1.5 in m ³ / s with
V = volume flow
k: factor that takes the temperature difference into account:
k = 1.5 if a corridor joins;
k = 1.8 if a usage unit is connected
b: door width in m
h: door height in m

This results in the dimensioning of the printing system:
Rated volume flow = volume flow for the door flow + leakage volume flow over leak points

For a conventional flushing system, the volume flow for the door flow is to be set at 10,000 m ³ / h in accordance with the model high-rise directive applicable in Germany, and correspondingly more for large stairwells.

From DE 198 41 540 A1 a security staircase is known in which each lock has an overflow opening which is provided with valve flaps, is attached above the door and the by means of a fan with overpressure Predeterminable volume flow is ventilated.

With the publication EP 0 995 955 A2 a similarly functioning Overpressure flap between a staircase and a downstream one Space to maintain constant pressure in the stairwell proposed.

Nothing is reported about the extremely short response times required both institutions seem to be very sluggish.

The publications DE 198 56 193 A1; DE 199 37 530 A1 and DE 199 37 532 A1 report on flushing systems with roof vents that have a motor Have actuating device. Such smoke vents are disturbing and maintenance-prone; they need electronic or electrical components some failure probability, have long response times and are weather permitting.

From the publication DE 198 49 863 A1 is still a spring-loaded Fire damper known for a ventilation duct. When there is a fire Melt the melting element and then move the flap from a rest position bring an irreversible closing position.

DE 199 19 701 A1 finally opened one by air pressure Overpressure valve disclosed, which receives a restoring torque via weights.

Previous controllable systems have a relatively unreliable and sluggish or Weather-dependent arrangement of components with a high probability of failure on.

Therefore, the problem underlying the invention is an improved one To propose methods and an improved device, with which a quick and system-independent steady-state response in less than one second can be guaranteed.

The problem is solved according to the invention by the features of the claims 1 and 9. Further developments of the invention are in the dependent claims described.

In a generic overpressure system, the invention includes Solution a fan with guide and stabilizer and at a standstill adjustable blades, integrated in a housing within a About printing apparatus; in the centrally arranged housing is a driven axial fan installed centrally and around this housing is a Bypass arranged with at least one self-closing flap. The Bypass can also be close in another version according to the invention of the overpressure apparatus can be arranged if from there one There is a possibility of backflow of air to the suction side of the fan.

A curve-stabilized axial fan comes as a fan Electric drive for use. The stabilization of the characteristic prevents that Axial fans usual demolition area in the left part of the characteristic. This Selection allows use in parallel operation.

The bypass has a preferably even number of symmetrical Single flaps with preferably perpendicular axes of rotation, the flaps are designed so that they are a when open Allow bypass flow around the axial fan and the maximum Pressure loss of the bypass flow in the overpressure device with the same size as the required overpressure is in the escape route and the flow effective Flap areas in a certain ratio to the housing Cross-sectional area are executed.

This is a lightweight system with symmetrical flows and designs proposed a prerequisite for responding as quickly as possible self-regulating smoke control system and low maintenance requirements.

The flap system is designed so that the opening or closing of the Flaps caused by air force moments or by means of a mechanical tension-compression Spring system is possible, the torque curve depending on increasing valve opening angle decreases, and a stable operating point (Intersection) of the course of the spring moments with the decreasing Air force moments are above 50 degrees, preferably at about 55-80 degrees Flap opening angle forms.

If several flaps are used, they are preferably vertical superimposed axes of rotation; for even-numbered bypass flaps, these are Axially positively connected; all flaps should be for simplicity and because of the more favorable flow conditions, the same Have swivel direction. This makes it easier to set the moments and calculate and design the device easily.

Preferably the axes of rotation of the flaps by means of bevel gears are best Gears, positively connected.

The procedure for smoke-free, especially escape and Escape routes taking into account the permissible pressure differences of the Air in adjacent hallways and stairwells with an overpressure system, therefore provides that around a, preferably central housing in the Overpressure device, with an axial fan to bypass a flow self-closing system of flaps is generated, being ensured is that the flaps under the action of a predetermined positive pressure open in the escape route and release the bypass.

This regulates the smoke control system without external sensors or Measuring devices automatically and continuously.

The procedure also provides that the necessary moments for opening the flaps are adjusted so that the pressure or air forces of the Sufficient flow in the bypass and the moments for closing the Flaps provided by a mechanical tension or compression spring system be, the intersection of both torque profiles so the maximum itself Setting opening area of the flaps determines, which makes an automatic direct-acting control system due to pressure changes in the escape route arises, which opens with a reaction time corresponding to the max. Escape route height or length (usually stairwell) below Taking into account the speed of sound and closing with a Response time proportional to the moment of inertia / restoring moment of the Spring system of the flaps works.

The system can therefore automatically regulate the following operating states:
All doors are closed.
To achieve the desired predeterminable overpressure, only as much air is brought into the pressure chamber (escape route) as is necessary to cover leakages on site.
The bypass flaps are open in this operating state.
A door is open.
If there is an outflow from the downstream rooms, the pressure drop leads to an immediate closing of the flaps and the open door cross-section is now flowed through in the direction of the fire chamber.
Use in flushing systems.
An outflow surface is provided in the upper part of the stairwell. The secured outflow can, however, be severely impaired by the flow around the building or by the direct influence of the wind, with the result that the pressure builds up too high and the doors can no longer be opened.
The bypass flaps inside the device ensure that this condition cannot occur.

The advantages of the system are obvious. All reactions of the plant take place automatically. Additional sensors, pressure regulators, actuators, Clamping and transfer points for the overpressure system as in the prior art required, can be omitted. This means minimizing possible Failure components and reduction of failure probabilities.

Using a drawing, the problems and solutions as well as advantages of Invention are shown in more detail.

Show it

Figure 1 is a front view of an overpressure apparatus according to the invention.

FIG. 2 shows a simplified longitudinal section through an apparatus according to FIG. 1, showing the effect of a fan when the bypass is closed;

Fig. 3 is a simplistic longitudinal section through an apparatus according to FIG 1 showing the effect of a fan with open bypass.

Fig. 4 is a snapshot representation of the aerodynamic forces and spring forces to different opening angles of the valve of the bypass;

Fig. 5 is a typical escape / staircase arrangement with downstream fire rooms and a pressure-smoke control system;

Fig. 6 perspective top view of a real version of an overpressure apparatus.

The same reference numerals in the following description refer to identical or functionally identical parts.

Overview of FIGS. 1-3 and 5

Both the supply air fan 2 are arranged in a central housing and the pressure relief flaps 3 , 3.1, which act automatically via a spring mechanism 6 , are arranged within the box device / overpressure apparatus 1 . These flaps open automatically when the excess pressure exceeds the desired value and create a bypass 4 to the suction side of the fan 2 .

Fig. 1 shows four symmetrically arranged around the housing with the fan valve 3.1, which together form the bypass system 3. Each flap 3.1 has a rotational or pivot axis 3.2 , about which it is opened in the same direction by the bypass flow 4 or the prevailing air forces and air moments in short-circuit operation against the restoring moments of the spring system 6 ( FIG. 3) or by means of spring forces or moments the spring system 6 is reset ( Fig. 2).

The opening force of the bypass flaps 3.1 is applied by an overpressure in the stairwell / escape route 5 ( FIG. 5). This is offset by a spring system 6 with a closing force / restoring force or torque. About the variation of the spring force by changing z. B. the pretension length or other parameters familiar to a person skilled in the art, the pressure difference at which the flaps are opened can be set. With the flaps open, part of the air quantity 4 circulates within the apparatus in this embodiment of the invention.

If the pressure drops due to opening doors 7 , the spring system 6 brings about an immediate closing movement of the flaps 3 . The rated volume flow V is now conveyed with the fan 2 in order to maintain the predeterminable excess pressure.

By the overpressure apparatus 1, a controlled excess pressure of z is in the stairwell. 5 B. 50 Pa built. The pressure is kept constant by automatically acting pressure relief flaps 3.1 within the overpressure apparatus, which provide bypass areas 3 to the suction side of the device when the permissible pressure difference is exceeded.

The system is controlled z. B. via smoke detectors 11 , which are arranged in front of each access door in the hallway or the lock 9 of the downstream rooms / offices 10 outside the protected area. Doors to the stairwell 5 and the lock 9 must be self-closing and at least fire-retardant.

When smoke is detected by the smoke detector 11 , the smoke protection pressure system, the overpressure apparatus 1 is put into operation. At the same time, signal horns and free-wheeling door closers can be activated on doors 7 . Each floor E represents a detector line. In the floor affected by the fire, windows 13 are opened automatically via an actuator. The outflow can also take place via a conventional L90 shaft, to which smoke extraction dampers are connected on each floor.

Only if there is a possibility of an outflow from the fire chamber 10 or from intermediate units, can it be ensured that when the staircase doors 7 are open, a flow can take place in the direction of the fire chamber.

The equipment typically also includes:
Control cabinet 15 , optical smoke switch 11 , alarm horn / flashing light combination 12 , free-wheel door closer, weather protection grille / shutter flap combination 14 for air supply to fan 2 , actuator (for window or smoke extraction flap 13 ).

Fig. 4 shows the torque curve in various operating situations of the printing system.

Six different courses of moments M in Ncm and a working line of the system according to the invention are shown in addition to different air force moments with the bypass closed, each over the opening angle a in degrees from 0-90 degrees. Legend for Fig. 4 ____ "Door closed" opening torque, free suction (220 Pa pressure)
-------- ▪ Opening moment freely blowing on the suction side (70-80 Pa)
-------- ▵ Opening moment freely blowing on the suction side (200 Pa)
-------- × Opening torque, suction on the pressure side, bypass open
-------- * Opening torque with suction line, closed on the pressure side
-------- ● opening torque with suction line; Bypass open
-------- □ work line
1idel air force torque (50 Pa)
2idel air force torque (100 Pa)
3idel air force torque (150 Pa)
4idel air force torque (200 Pa)

It results from the professional design of the apparatus Bypass each clear intersection of the work line with everyone Torque profiles / opening moments.

Fig. 6 shows a specific embodiment of the overpressure apparatus 1 with fan 2 in the central housing as it can be used for keeping the escape routes 5 free from smoke.

The bypass 3 is composed of four flaps 3.1 around the housing. The flaps 3.1 pivot about the axes 3.2 , the synchronism of which is ensured by bevel gears 3.3 . So that the spring 6 , adjusted in its effect / resilience for the flaps 3.1 by choosing a suitable length and tensile force via z. B. variably usable wire thicknesses of a coil spring, with each opening angle of the flaps in function, they are connected via guide links 3.4 with the flaps 3.1 .

Claims (10)

1.Device system for keeping escape and rescue routes smoke-free, taking into account the permissible pressure differences in the air in adjacent corridors and stairwells with an overpressure system, comprising a fan with guide device and stabilizer and adjustable blades at standstill, integrated in a housing, characterized in that inside an overpressure device ( 1 ), a drivable axial fan ( 2 ) is installed centrally in the centrally arranged housing and a bypass with at least one self-closing flap ( 3 ) is arranged around this housing or in the vicinity of the overpressure device with a backflow option for the air to the suction side of the fan , 2. Device system according to claim 1, characterized in that the bypass comprises an even number of symmetrical individual flaps ( 3.1 ) with axes of rotation ( 3.2 ), the flaps being designed such that they have a bypass flow ( 4 ) around the axial fan ( 2 ) and the maximum pressure loss of the bypass flow in the overpressure device is the same size as the required overpressure in the escape route ( 5 ) and the flow-effective surfaces of the flaps ( 3 ) are designed in a certain ratio to the flow-effective cross-sectional area of the housing. 3. Device system according to claim 1 or 2, characterized in that that the ratio of the flow effective cross sectional area of the Housing for flow-effective bypass area ≥1.4, preferably 1.6 to 2.1, and the ratio of housing length to housing height ≥1.1, is preferably 1.15 to 1.3. 4. Device system according to one of the preceding claims, characterized in that the flap system is designed such that the opening or closing of the flaps by air force moments or by means of a mechanical tension-compression spring system, the torque curve depending on the increasing Damper opening angle decreases, and a stable working point (Intersection) of the course of the spring moments with the decreasing Air force moments are above 50 degrees, preferably around 55-80 degrees, flap opening angle (a) forms. 5. Device system according to one of the preceding claims, characterized in that perpendicular to each other The axes of rotation of the even-numbered bypass flaps are positive are connected. 6. Device system according to claim 5, characterized in that the Axes of rotation of the flaps can be positively connected by means of bevel gears are. 7. Device system according to one of the preceding claims, characterized in that all flaps for a same-minded Swivel direction are designed. 8. Device system according to one of the preceding claims, characterized in that when the Overpressure system the bypass flaps are designed to be weight-compensated. 9. A method for keeping escape and rescue routes smoke-free, taking into account the permissible pressure differences in the air in adjacent corridors and stairwells with an overpressure device with an axial fan in a housing, characterized in that around the housing with the axial fan ( 2 ) or near the A bypass flow ( 4 ) is generated by means of a self-closing system of flaps ( 3 ), whereby it is ensured that the flaps ( 3 ) open under the effect of a predetermined overpressure in the escape route ( 5 ) and release the bypass ( 4 ). 10. The method according to claim 9, characterized in that the moments for opening the flaps are set so that the pressure forces or air forces of the flow in the bypass ( 4 ) are sufficient and the moments for closing the flaps by a mechanical pull or Compression spring system ( 6 ) are provided, the intersection of both torque curves thus determining the maximum opening area of the flaps, which creates an automatically acting control system as a result of pressure changes in the escape route, which opens with a reaction time corresponding to the max. Escape route height or escape route length taking into account the speed of sound and finally with a reaction time proportional to the mass moment of inertia / restoring moment of the spring system of the flaps.