FI71614B - TRYCKREDUCERINGSKAMMARE FOER VENTILATIONSANORDNINGAR - Google Patents

Description

71 61 4 PRESSURE REDUCTION CHAMBER FOR VENTILATION EQUIPMENT - TRYCKREDU- ceringskammare för ventilationsanordningar , such as a pipe section the size of the inlet pipe, which provides a constant flow of air into the housing and further into the space to be ventilated from the housing.

Air conduction into the room should be as even as possible to avoid draft. For this purpose, pressure relief chambers, also known as i1 manjako 1 boxes and i1 changeover valves, are used. In addition, it must be possible to adjust the air flow as quietly as possible and the volume flow should be able to be measured with sufficient accuracy. Various dampers or iris controllers are used to control the airflow, which partially close the flow opening and at the same time generate a loud noise and do not distribute the air evenly. In order to equalize the air flow, torn plates and laminar equalizers installed in the i1 maniac boxes after the control damper, which consist of a small-hole cell 1, are used. Laminar equalizers are very prone to clogging. To reduce the noise caused by the damper dampers, a sound-absorbing curtain is used in the air distribution boxes. However, the sound-absorbing cladding is not sufficient to eliminate the sound generated by the airflow dampers and the iris controls. For the measurement of the volume flow of air, the measurement of the local pressure difference across the perforated plates is used, through which the volume flow of the air ti1 is determined. However, the measurement of the air volume flow by this method is inaccurate because the position of the damper disturbs the pressure field very strongly and the measurement error of the air volume flow is easily more than 30-50%.

More than half of the energy losses in buildings are due to ventilation. Now and in the future, energy saving measures in buildings require sufficiently precise management of energy flows. This is not possible 71614 unless the air volume flows (= energy flows) of the 1 1 exchange or 1 fences can be measured more reliably and adjusted more easily.

Previously known ways of conducting air flow into a room through tubular sheaths provided with openings are presented in Finnish patent applications no. 802963, 813762 and 823518.

In patent application no. 802963 discloses an air flow divider and control device fitted to an open end or air duct of an air duct and having a tubular sheath that fits tightly within the duct. Since the casing of the device and possibly also the end are provided with openings, the device distributes the air evenly, for example in the room. The length of the part of the device protruding from the duct is adjusted by pushing the device into the duct or pulling it out of the duct.

In patent applications no. 813762 and 823518 show devices for conducting an air flow to a living space. The devices comprise openings in the air duct with openings and at least three nested tubular casings which act as equalizers and retarders of the air flow before the air enters the living space through the openings.

A particular disadvantage of the devices in the above patent applications is that they are not equipped with the technology required for measuring the volume flow of air.

The previously known methods for measuring the volume flow of ventilation valves and air distribution units require a virtually undisturbed flow profile at the measuring point in order for the measurement error to be sufficiently small. In general, in practical installation cases, the flow profile is not sufficiently undisturbed without special flow straightening and smoothing devices 1, because the flow channels do not have sufficiently long straight channel sections in which the flow profile can be smoothed. Thus, the measurement accuracy has remained poor. The measurement accuracy has also been impaired by the fact that the devices could not be set to unambiguous adjustment positions due to manufacturing deviations. In some

II

In 3,71614 cases, a reliable measurement result could not be reasonably achieved, because the flow control devices used in commonly used air jets and in connection with ventilation valves also confuse the flow profile and at the same time achieve a reliable measurement result.

The object of the invention is to provide a new type of pressure relief chamber. The depressurization chamber according to the invention is characterized in that it comprises two pressure measuring chambers with one or more openings which open from one pressure measuring chamber inside the inner chamber and from the second pressure measuring chamber outside the inner chamber into the housing space. The invention provides a depressurization chamber which measures and regulates the volume flow of air, distributes the air evenly to the ventilation valve, acts as a muffler and generates very little sound itself, despite the large pressure drop. The volume flow of air is measured by means of a pressure difference across a tubular or spherical inner chamber. Special measuring chambers are used to measure the pressure difference.

A preferred embodiment of the invention is characterized in that the pressure measuring chambers are located as two flat overlapping circular chambers at the end of the inner chamber, where the pressure inlets open circumferentially either parallel to the inner chamber or perpendicular to the inner chamber. In this way, a technically simple, inexpensive and reliable solution for the pressure relief chamber is obtained. The purpose of measuring the volume flow of air is to obtain an even more accurate and larger reading in the detection of the pressure difference and thus a higher measurement accuracy of the volume flow. It is also intended to provide greater measurement accuracy, especially in highly disturbed, e.g. asymmetric, flow profiles. The device according to the invention achieves a measurement accuracy of better than 5-10% even in difficult flow conditions. The adjustment position also does not affect the measurement accuracy.

Another embodiment of the invention is characterized in that the inner chamber is a cylindrical tube with openings in annular rows, and the inner chamber is surrounded to a partial length of 71614 by a collar movable in the longitudinal direction of the inner chamber and closing the rows of holes. By blocking the openings in the inner chamber, for example by means of a movable collar that can be locked in different adjustment positions, the air flow can be adjusted and at the same time a sufficient pressure difference can be achieved for measuring the air volume flow even with small air flows.

A further preferred embodiment of the invention is further characterized in that the inner chamber consists of an electric heating resistor.

The solution according to the invention achieves, among other things, the following advantages: The pressure relief chamber itself measures the air flow passing through itself with one differential pressure measurement.

- The pressure relief chamber accurately measures the air volume flow even in the disturbed air flow.

- The pressure relief chamber accurately measures the air volume flow even at low airflows (the pressure difference used to measure the airflow is sufficient even at low airflows).

- The air volume flow measuring device has no space requirement outside the depressurization chamber.

- The air volume flow measuring device is also suitable for use with a volume flow control device, such as a collar. as a measuring control device.

- The air flow control device, ie the collar, does not interfere with the air volume flow measurement.

- The adjustment position of the air flow control device can be unambiguously determined without unreasonable manufacturing tolerances.

- The air volume flow can be measured unambiguously without the hysteresis effect due to the control device.

- Calibration of the air volume flow scale is easy because the control device allows clearances which, however, do not affect the measurement accuracy.

- The volume flow of the air can be adjusted and measured with a large pressure difference, while the device's own sound development remains low.

71614 - The pressure relief chamber distributes the air evenly to the ventilation valve.

- The structure of the pressure relief chamber is simple.

- An inner chamber with openings in the pressure relief chamber can also act as an electric heating element and the pressure relief chamber can thus act as a heating device.

- The connection duct of the pressure relief chamber can be equipped with a fire damper.

The invention will now be described by way of example with reference to the accompanying drawing, in which

Figure 1 shows the pressure relief chamber in section 1.

Figure 2 shows point II of Figure 1 enlarged.

The pressure relief chamber is intended to be connected to the ventilation ductwork. The pressure relief chamber consists of a housing 2 to be connected to the inlet pipe 1 of the ventilation duct, inside which is an inner chamber 3 with holes as an extension of the inlet pipe 1, such as a pipe section the diameter of the inlet pipe 1, which provides a constant air flow to and from the housing. The depressurization chamber comprises two pressure measuring chambers 4, 5 with one or more openings 6, 7 which open from the second pressure measuring chamber 4 inside the inner chamber 3 and from the second pressure measuring chamber 5 outside the inner chamber 3 into the housing space 2. The main measuring chambers 4 are located as a circular chamber at the end of the inner chamber 3, where the pressure inlets 6, 7 open circumferentially either parallel to the inner chamber or perpendicular to the inner chamber. The inner chamber 3 is a cylindrical tube, in which the openings 8 are located in annular rows, and which inner length is surrounded in part by a collar 9 movable in the longitudinal direction of the inner chamber 3 and closing the rows of holes.

It will be apparent to those skilled in the art that the invention is not limited to the examples set forth above but may vary within the scope of the claims set forth below. Thus, the shape of the inner chamber 71614 need not be tubular, but may just as well be some other shape, such as spherical.

Il

Claims (4)

A pressure relief chamber for devices, which chamber is intended to be connected to a ventilation duct and which consists of a housing (2) to be connected to the inlet pipe (1) of the ventilation duct, inside which there is an inner chamber (3) with holes as an extension of the inlet pipe. providing a uniform air flow into the housing and further into the space to be ventilated from the housing, characterized in that the pressure relief chamber comprises two pressure measuring chambers (4,5) with one or more openings opening from the second pressure measuring chamber (4) inside the inner chamber (3) and the second pressure measuring chamber (5) outside (3) into the housing (2). A pressure relief chamber according to claim 1, characterized in that the pressure measuring chambers (4,5) are located as two flat overlapping circular chambers at the end of the inner chamber, the pressure inlets (6, 7) opening circumferentially either parallel to the inner chamber or perpendicular to the inner chamber. Pressure relief chamber according to Claim 1 or 2, characterized in that the inner chamber (3) is a cylindrical tube in which the openings (8) are located in annular rows, the inner chamber being surrounded in part by a collar (9) movable longitudinally and closing the rows of holes. Pressure relief chamber according to one of the preceding claims, characterized in that the inner chamber consists of an electric heating element.