GB2197456A

GB2197456A - Dampers

Info

Publication number: GB2197456A
Application number: GB08626900A
Authority: GB
Inventors: Andrew John Robertson
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1986-11-11
Filing date: 1986-11-11
Publication date: 1988-05-18
Also published as: GB8626900D0

Abstract

A damper for use in a constant velocity mode within a duct 2 includes a pivotally mounted asymmetric blade 4 carrying externally of the duct a permanently magnetic counterbalance arm sector 8. An electromagnet 9 is energised to vary the position of the blade 4. <IMAGE>

Description

SPECIFICATION Dampers This invention concerns improvements in or relating dampers of the kind installed in ducts to control the flow of fluid there through.

In particular, the invention has reference to a damper of the type described in our co-pending U.K Patent Application No. 85/29443 which essentially comprises an asymmetric blade mounted within a duct and giving by virtue of its profile, a constant velocity characteristic flow through the duct. The damper of that invention relied upon a counterbalance weight for control and whilst this is perfectly adequate, in some applications a more positive and indeed flexible control is desirable, if not necessary.

An object of the invention is therefore to provide an improved damper having a positive control facility.

According to the invention a damper for use in a constant Velocity mode within a duct, the damper including an asymetric blade pivotally mountable within a duct, a magnetic arm mountable externally of the duct and movable in -unison with the blade, and an electro magnet associated with the arm and operable to effect the desired movement of the arm and the damper blade.

The blade is conveniently circular and has diametrically opposed formations provided to give asymmetry. For example, a segment of the circular blade is bent over along the chordal line in an opposite sense at each diametal location thereby providing asymmetry.

The magnetic arm may be counterbalanced and may be in the form of a quadrant or similar configuration. The electromagnet may be in the form of a caliper embracing a marginal portion of the arm in spaced relation thereto.

By way of example only, one embodiment of damper according to the invention is.described below with reference to the accompanying drawings in which: Figure 1 is a diagrammatic cross-section through a duct incorporating the damper; Figure 2 is a fragmentary view of part of the damper shown in Fig. 1; and Figure 3 is a plan view of the part shown in Fig. 2.

Referring to the drawings, a circular section duct 2 has pivotally mounted therein a circular damper blade 4 carried on a spindle 6 which passes through the duct along a diameter thereof to terminate externally thereof. The spidle 6 has affixed thereto at its end outside the duct 2 a quadrant-shaped counterbalance arm 8 which is a permanent magnet.

Electromagnets 9 in caliper configuration are disposed in spaced relation to a marginal portion of the arm 8 as can be seen from Figs. 2 and 3. A coil 10 connectible to a D.C. Supply (not shown) is provided for energising the magnets 9.

In operation, the setting of the damper blade 4 is controlled by the current to the coil 10 which energises the electromagnets 9.

Variation of this current can therefore give a wide control range for the damper blade setting. An advantage of this damper over the simple counterbalance kind is in easier installation since no on site setting is required, the control lying in the electrical supply modulation. The damper also has greater versatility because it is infinitely variable and since control is electrical, the damper has a wide range of application. For example, it can be employed not only for pneumatic transport systems, but also for the control of air supply to a burner.

1. A damper for use in a constant velocity mode within a duct, the damper including an asymmetric blade pivotally mountable within a duct, a magnetic arm mountable externally of the duct and movable in unison with the blade, and an electromagnet associated with the arm and operable to effect the desired movement of the arm and the damper blade.

2. A damper according to claim 1 in which the blade is circular and has diametrically opposed formations provided to give asymmetry.

3. A damper according to claim 2 in which a segment of the circular blade is bent over along a chordal line in an opposite sense at each diametral location thereby providing as asymmetry.

4. A damper according to any one of the preceding claims in which the magnetic arm is counterbalanced.

5. A damper according to any one of the preceding claims in which the magnetic arm is quadrant shaped.

6. A damper according to claim 5 in which the electromagnet is in the form of a caliper embracing a marginal portion of the arm.

7. A damper substantially as hereinbefore described with reference to Figs. 1, 2 and 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Dampers This invention concerns improvements in or relating dampers of the kind installed in ducts to control the flow of fluid there through. In particular, the invention has reference to a damper of the type described in our co-pending U.K Patent Application No. 85/29443 which essentially comprises an asymmetric blade mounted within a duct and giving by virtue of its profile, a constant velocity characteristic flow through the duct. The damper of that invention relied upon a counterbalance weight for control and whilst this is perfectly adequate, in some applications a more positive and indeed flexible control is desirable, if not necessary. An object of the invention is therefore to provide an improved damper having a positive control facility. According to the invention a damper for use in a constant Velocity mode within a duct, the damper including an asymetric blade pivotally mountable within a duct, a magnetic arm mountable externally of the duct and movable in -unison with the blade, and an electro magnet associated with the arm and operable to effect the desired movement of the arm and the damper blade. The blade is conveniently circular and has diametrically opposed formations provided to give asymmetry. For example, a segment of the circular blade is bent over along the chordal line in an opposite sense at each diametal location thereby providing asymmetry. The magnetic arm may be counterbalanced and may be in the form of a quadrant or similar configuration. The electromagnet may be in the form of a caliper embracing a marginal portion of the arm in spaced relation thereto. By way of example only, one embodiment of damper according to the invention is.described below with reference to the accompanying drawings in which: Figure 1 is a diagrammatic cross-section through a duct incorporating the damper; Figure 2 is a fragmentary view of part of the damper shown in Fig. 1; and Figure 3 is a plan view of the part shown in Fig. 2. Referring to the drawings, a circular section duct 2 has pivotally mounted therein a circular damper blade 4 carried on a spindle 6 which passes through the duct along a diameter thereof to terminate externally thereof. The spidle 6 has affixed thereto at its end outside the duct 2 a quadrant-shaped counterbalance arm 8 which is a permanent magnet. Electromagnets 9 in caliper configuration are disposed in spaced relation to a marginal portion of the arm 8 as can be seen from Figs. 2 and 3. A coil 10 connectible to a D.C. Supply (not shown) is provided for energising the magnets 9. In operation, the setting of the damper blade 4 is controlled by the current to the coil 10 which energises the electromagnets 9. Variation of this current can therefore give a wide control range for the damper blade setting. An advantage of this damper over the simple counterbalance kind is in easier installation since no on site setting is required, the control lying in the electrical supply modulation. The damper also has greater versatility because it is infinitely variable and since control is electrical, the damper has a wide range of application. For example, it can be employed not only for pneumatic transport systems, but also for the control of air supply to a burner. CLAIMS