GB2129917A

GB2129917A - Pressure venting systems

Info

Publication number: GB2129917A
Application number: GB08329864A
Authority: GB
Inventors: George Applegate
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-11-10
Filing date: 1983-11-09
Publication date: 1984-05-23
Also published as: GB8329864D0; GB2129917B

Abstract

A small blow-down tank operationally separate from any main blow-down tank provided for the main boiler of a steam boiler has a removable top coverplate (42) attached to a vertical inlet pipe (43) and to a short standpipe (44) acting as a vent. Attached to the pipe (43, 44) is an internal baffle system which is removable therewith. <IMAGE>

Description

SPECIFICATION Pressure venting systems This invention relates to fluid pressure systems such as steam boilers, though the invention may also be applied to other pressure systems such as autoclaves.

Many pressure systems include auxiliary instruments or controls, which are connected to the main pressure vessel and may occasionally need to be drained off, for example for maintenance, cleaning, or replacement. It is an object of the invention to provide means for draining off or clearing out such auxiliary instruments in a simple, effective, and economical manner.

Broadly stated the invention consists in a fluid pressure plant comprising a main pressure vessel having external auxiliary control or indicating devices connected to the pressure system, and means for venting the devices through a small blow-down tank operationally separate from any blow-down tank provided for the main pressure vessel.

It is a preferred feature of the invention that the small blow-down tank should not be connected to the main pressure system of the pressure plant except through the said control or indicating devices. Conveniently the small blow-down tank is positioned on or adjacent the main pressure vessel.

The blow-down tank preferably comprises a fluid container having an outlet, and a removable upper section which incorporates an inlet to be connected to the auxiliary devices, and a vent. The inlet on the upper section preferably includes a vertical standpipe, and the vent preferably includes a standpipe shorter than that of the inlet. The blow- down tank also preferably includes an internal baffle or liquid retainer cup, connected to and removable with one of the inlets or outlets to the container.

The blow-down tank will normally have a valve controlled bottom drain and preferably also includes a valve controlled outlet including a duct having an opening positioned above the bottom of the container.

The invention may be performed in various ways and one specific embodiment together with a number of possible modifications will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of a steam boiler plant having a small blow-down tank attached, in accordance with the invention, Figure 2 is a sectional side elevation on an enlarged scale illustrating the blow-down tank of Figure 1, and Figures 3-6 showing further details.

In this example the invention is applied to a boiler plant for heating or steam generation purposes comprising a main pressure steam boiler 10 having a fuel and combustion air supply system indicated generally at 11, and an exhaust stack 12. The boiler is provided with a number of auxiliary indicating and control instruments and devices, which communicate with the main pressure vessel of the boiler and in this example these devices comprise two water level controls 1 5, 16 and a pair of sight glasses 1 7. All of these may need to be drained off or cleared out for maintenance or other purposes, and in accordance with the invention this is achieved through a small blow-down tank 18, which is quite independent of any main blow-down tank provided for draining off the main pressure vessel.The small blow-down tank 1 8 has an inlet 20 connected to three branch lines 21 , 22, 23 each of which includes a nonreturn valve 24 and a closure valve 25. The blowdown tank has a top outlet 28 connected to a vent pipe 29, which may lead to atmosphere, as shown at 30, or may be connected at 31 to the exhaust stack 12. The blow-down tank also has a bottom drain connection 32 controlled by a cock 33, and a further outlet 34 controlled by a valve 35.

The blow-down tank is illustrated in more detail in Figure 2. It comprises a cylindrical pressure vessel 40, having external mounting brackets 39 and formed with a top flange 41 rigidly welded in position and a removable top coverplate 42, which can be bolted down onto the flange 41 with an interposed annular seal. The coverplate 42 has a long vertical inlet pipe 43 connected to the inlet 20 and extending downwards to a point below the halfway level of the container. There is a shorter standpipe 44 acting as a vent and connected to the vent outlet 28. Attached to these standpipes 43, 44 is an internal baffle system which comprises a cup 45, with a small bottom drain hole 52, a circular baffle plate 46, and outlet tube 47, interconnected by a welded strap 48 and attached to the standpipe 43 by a further welded strap 49.Parts of the baffle structure may be attached to one or other standpipe by further struts, but essentially the whole baffle system is removable from the top of the container complete with the top coverplate 42 and the inlet and vent standpipes 43, 44.

The container also includes an elbow 50, with a downward depending pipe 51, connected to the side outlet 34. This elbow pipe may be fixed in position or may be removable.

Thus it will be seen that the blow-down tank is extremely simple and economical to manufacture and most effective in operation. If it is required to clean out the tank or its components all the essential elements can be removed complete in one unit at the top.

1. A fluid pressure plant comprising a main pressure vessel having external auxiliary control or indicating devices connected to the pressure system, and means for venting the devices through a small blow-down tank operationally separate from any blow-down tank provided for the main pressure vessel.

2. A plant according to Claim 1, in which the small blow-down tank is not connected to the main pressure system of the pressure vessel

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pressure venting systems This invention relates to fluid pressure systems such as steam boilers, though the invention may also be applied to other pressure systems such as autoclaves. Many pressure systems include auxiliary instruments or controls, which are connected to the main pressure vessel and may occasionally need to be drained off, for example for maintenance, cleaning, or replacement. It is an object of the invention to provide means for draining off or clearing out such auxiliary instruments in a simple, effective, and economical manner. Broadly stated the invention consists in a fluid pressure plant comprising a main pressure vessel having external auxiliary control or indicating devices connected to the pressure system, and means for venting the devices through a small blow-down tank operationally separate from any blow-down tank provided for the main pressure vessel. It is a preferred feature of the invention that the small blow-down tank should not be connected to the main pressure system of the pressure plant except through the said control or indicating devices. Conveniently the small blow-down tank is positioned on or adjacent the main pressure vessel. The blow-down tank preferably comprises a fluid container having an outlet, and a removable upper section which incorporates an inlet to be connected to the auxiliary devices, and a vent. The inlet on the upper section preferably includes a vertical standpipe, and the vent preferably includes a standpipe shorter than that of the inlet. The blow- down tank also preferably includes an internal baffle or liquid retainer cup, connected to and removable with one of the inlets or outlets to the container. The blow-down tank will normally have a valve controlled bottom drain and preferably also includes a valve controlled outlet including a duct having an opening positioned above the bottom of the container. The invention may be performed in various ways and one specific embodiment together with a number of possible modifications will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of a steam boiler plant having a small blow-down tank attached, in accordance with the invention, Figure 2 is a sectional side elevation on an enlarged scale illustrating the blow-down tank of Figure 1, and Figures 3-6 showing further details. In this example the invention is applied to a boiler plant for heating or steam generation purposes comprising a main pressure steam boiler 10 having a fuel and combustion air supply system indicated generally at 11, and an exhaust stack 12. The boiler is provided with a number of auxiliary indicating and control instruments and devices, which communicate with the main pressure vessel of the boiler and in this example these devices comprise two water level controls 1 5, 16 and a pair of sight glasses 1 7. All of these may need to be drained off or cleared out for maintenance or other purposes, and in accordance with the invention this is achieved through a small blow-down tank 18, which is quite independent of any main blow-down tank provided for draining off the main pressure vessel.The small blow-down tank 1 8 has an inlet 20 connected to three branch lines 21 , 22, 23 each of which includes a nonreturn valve 24 and a closure valve 25. The blowdown tank has a top outlet 28 connected to a vent pipe 29, which may lead to atmosphere, as shown at 30, or may be connected at 31 to the exhaust stack 12. The blow-down tank also has a bottom drain connection 32 controlled by a cock 33, and a further outlet 34 controlled by a valve 35. The blow-down tank is illustrated in more detail in Figure 2. It comprises a cylindrical pressure vessel 40, having external mounting brackets 39 and formed with a top flange 41 rigidly welded in position and a removable top coverplate 42, which can be bolted down onto the flange 41 with an interposed annular seal. The coverplate 42 has a long vertical inlet pipe 43 connected to the inlet 20 and extending downwards to a point below the halfway level of the container. There is a shorter standpipe 44 acting as a vent and connected to the vent outlet 28. Attached to these standpipes 43, 44 is an internal baffle system which comprises a cup 45, with a small bottom drain hole 52, a circular baffle plate 46, and outlet tube 47, interconnected by a welded strap 48 and attached to the standpipe 43 by a further welded strap 49.Parts of the baffle structure may be attached to one or other standpipe by further struts, but essentially the whole baffle system is removable from the top of the container complete with the top coverplate 42 and the inlet and vent standpipes 43, 44. The container also includes an elbow 50, with a downward depending pipe 51, connected to the side outlet 34. This elbow pipe may be fixed in position or may be removable. Thus it will be seen that the blow-down tank is extremely simple and economical to manufacture and most effective in operation. If it is required to clean out the tank or its components all the essential elements can be removed complete in one unit at the top. CLAIMS

2. A plant according to Claim 1, in which the small blow-down tank is not connected to the main pressure system of the pressure vessel except through the said control or indicating devices.

3. A pressure plant according to Claim 1 or Claim 2, in which the small blow-down tank is positioned on or adjacent the main pressure vessel.

4. A blow-down tank for use in a pressure plant according to Claim 1 , 2, or 3, comprising a fluid container having an outlet, and a removable upper section which incorporates an inlet to be connected to the auxiliary devices, and a vent.

5. A blow-down tank according to Claim 4, in which the inlet on the upper section includes a vertical standpipe.

6. A blow-down tank according to Claim 5, in which the vent on the upper section includes a standpipe shorter than that of the inlet.

7. A blow-down tank according to any of Claims 4 to 6, having a valve-controlled drain, and a valve-controlled outlet including a duct having an opening positioned above the bottom of the container.

8. A blow-down tank according to any of Claims 4 to 7, including an internal baffle or liquid retainer cup, connected and removable with one of the inlet or outlets to the container.

9. A fluid pressure plant and a blow-down tank for use therein substantially as described with reference to the accompanying drawings.