GB2276932A - Surface dressing equipment and method - Google Patents

Surface dressing equipment and method Download PDF

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Publication number
GB2276932A
GB2276932A GB9406788A GB9406788A GB2276932A GB 2276932 A GB2276932 A GB 2276932A GB 9406788 A GB9406788 A GB 9406788A GB 9406788 A GB9406788 A GB 9406788A GB 2276932 A GB2276932 A GB 2276932A
Authority
GB
United Kingdom
Prior art keywords
chamber
outlet
elongate member
valve unit
valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9406788A
Other versions
GB2276932B (en
GB9406788D0 (en
Inventor
David Nicholas Kilner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shell Internationale Research Maatschappij BV
Original Assignee
Shell Internationale Research Maatschappij BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shell Internationale Research Maatschappij BV filed Critical Shell Internationale Research Maatschappij BV
Publication of GB9406788D0 publication Critical patent/GB9406788D0/en
Publication of GB2276932A publication Critical patent/GB2276932A/en
Application granted granted Critical
Publication of GB2276932B publication Critical patent/GB2276932B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K41/00—Spindle sealings
    • F16K41/02—Spindle sealings with stuffing-box ; Sealing rings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/30—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to control volume of flow, e.g. with adjustable passages
    • B05B1/3033—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to control volume of flow, e.g. with adjustable passages the control being effected by relative coaxial longitudinal movement of the controlling element and the spray head
    • B05B1/304—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to control volume of flow, e.g. with adjustable passages the control being effected by relative coaxial longitudinal movement of the controlling element and the spray head the controlling element being a lift valve
    • B05B1/3046—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to control volume of flow, e.g. with adjustable passages the control being effected by relative coaxial longitudinal movement of the controlling element and the spray head the controlling element being a lift valve the valve element, e.g. a needle, co-operating with a valve seat located downstream of the valve element and its actuating means, generally in the proximity of the outlet orifice
    • B05B1/306—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to control volume of flow, e.g. with adjustable passages the control being effected by relative coaxial longitudinal movement of the controlling element and the spray head the controlling element being a lift valve the valve element, e.g. a needle, co-operating with a valve seat located downstream of the valve element and its actuating means, generally in the proximity of the outlet orifice the actuating means being a fluid
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C19/00—Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving
    • E01C19/12—Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving for distributing granular or liquid materials
    • E01C19/16—Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving for distributing granular or liquid materials for applying or spreading liquid materials, e.g. bitumen slurries
    • E01C19/17—Application by spraying or throwing
    • E01C19/176—Spraying or throwing elements, e.g. nozzles; Arrangement thereof or supporting structures therefor, e.g. spray-bars
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K31/00—Actuating devices; Operating means; Releasing devices
    • F16K31/12—Actuating devices; Operating means; Releasing devices actuated by fluid
    • F16K31/122—Actuating devices; Operating means; Releasing devices actuated by fluid the fluid acting on a piston
    • F16K31/1221—Actuating devices; Operating means; Releasing devices actuated by fluid the fluid acting on a piston one side of the piston being spring-loaded

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Nozzles (AREA)

Abstract

A valve unit that can be used in a spray bar for spraying road dressing comprises a housing (1) defining a chamber (2) of fixed volume having an inlet (3) and an outlet (4) for the dressing, an elongate member (6) that can reciprocate in the housing and that has, within the chamber, an outlet closure member (5) biased into sealing engagement with the outlet, e.g. by means of a spring (9). The unit is adapted for opening of the outlet by independent external action on the elongate member against the bias, e.g. by means of a pneumatic system (10, 11, 12). A part 13 allows leaking dressing material to escape from the unit without reaching the pneumatic system. <IMAGE>

Description

SURFACE DRESSING EQUIPMENT AND METHOD Field of the Invention This invention relates to apparatus for use in surface dressing, e.g. of roads and pavements, and to its use.
Background of the Invention Road dressing involves the spraying of a liquid dressing composition at high temperature, e.g. about 200"C, usually via a spray bar on the rear of a suitable vehicle. The dressing or binder composition is applied through a number of valve units.
Each must be capable of satisfactory action over a long period, under the given conditions, and it may be desirable to allow independent actuation of the valve.
Figure 1 of the accompanying drawings shows a section of a spray bar including a known valve unit (in the closed position).
In general terms, the unit comprises a housing defining a chamber, an inlet and an outlet for liquid dressing material, and an elongate member that can reciprocate in the housing and that has an outlet closure member which, by virtue of a spring, is biased into sealing engagement with the outlet.
The hydraulic pressure of the material being sprayed assists the valve's closing forces. This may represent more than 50% of the force required to seal the outlet.
More specifically, the known unit is adapted for opening of the outlet by (downward) pneumatic action on the elongate member, against the bias. For this purpose, the chamber defines the cylinder of a piston-and-cylinder arrangement, and the volume through which the binder moves is variable.
The existing device suffers from several disadvantages.
Firstly, the dressing may leak into the pneumatic system.
Secondly, it is prone to failure to open or close fully, so causing a loss in flow rate. Thirdly, its actuation is sluggish, resulting in staggered starts and finishes between different units in one spray bar.
The present invention is based on an appreciation of the reasons for these problems, and the provision of a valve unit which avoids their primary causes.
Summary of the Invention According to the present invention, in a valve unit of the type generally described above, the outlet closure member is within the chamber. The chamber may be of fixed volume. In consequence, opening the outlet against suitable biasing means involves upward rather than downward movement of the elongate member.
The known unit is subject to material carry-over and piston 0-ring failure, resulting in binder leakage into the pneumatic system. That can simply be avoided, in accordance with the present invention, because the chamber and a pneumatic system are independent.
In the known unit, the return spring operates at the limits of its performance in relation to its length, and the required length of stroke. This causes closing problems, exhibited as over-run and staggered finishes. The cause of these problems can be simply eliminated by providing a longer spring.
In the known unit, hydraulic pressure of dressing material acts against what is effectively a piston within the chamber.
Accordingly, the surface area of the moving components in contact extends over the entire circumference of the piston. The resultant leakage and O-ring failure are substantially avoided, in accordance with the present invention, by the avoidance of a piston within the chamber and the provision of a much smaller surface area of moving parts in contact.
Description of the Invention More particularly, a valve unit of the present invention is of the plug-type. By the provision of a port independent from the chamber in which binder is present and from any hydraulic system acting against the bias to open the valve, atmospheric drainage can be provided between the material section and the air system.
This prevents contamination of the -pneumatic pipework and valves.
Such support also provides a convenient access point, e.g. for lubrication.
A pneumatic opening system for the purposes of the present invention may comprise, in the housing, a further inlet for fluid, independent from the chamber and any port as defined above, the fluid acting on a flange provided on the elongate member.
As indicated above, Figure 1 of the accompanying drawings illustrates the prior art. The present invention will now be described by way of example only with reference to Figure 2 of the accompanying drawings; Fig. 2 is a cross-sectional view of a valve unit embodying the present invention, with reference numerals that are also given in Fig. 1 where they illustrate corresponding components.
Fig. 2 shows a valve unit as part of a spray bar 1 (cut away). The unit comprises a housing, e.g. of steel, defining a chamber 2 having an inlet 3 and an outlet 4. In the position shown, the outlet 4 is closed by a head 5 threaded onto a valve stem 6. The correct shut preload can be adjusted, and the valve head 5 locked onto the stem 6, by means of a grub screw 7. The valve head 5 comprises a steel body with a polytetrafluoroethylene (PTFE) insert machined to give a 45" seat angle which matches the outlet 4. The outlet 4 is provided as part of an exit port 8.
The valve head is biased into sealing engagement with the outlet 4 by means of a spring 9. The length of the spring is sufficient to maintain an almost constant closing force.
Hydraulic pressure of the dressing material aids sealing by action on the valve head.
The valve stem can reciprocate within the housing. A sealing system around the stem is provided by, for example, a PTFE chevron seal and conventional "VITON" (Trade Mark) O-rings.
The valve stem has, at the opposite end from the valve head, a piston member 10 mounted within a further chamber 11. The housing comprises a further inlet 12 through which fluid (conveniently air) under pressure can be introduced to act against the piston 10 and open the valve against the bias and material hydraulic pressure. This further chamber 11 is independent from the chamber holding the material.
The housing also comprises an independent port 13. This port allows leaking dressing material to escape from the unit without reaching the pneumatic system, and also provides access.
The air port to the pneumatic cylinder is positioned such that additional fittings are not required. The piston-andcylinder assembly may be double-acting, if desired.
A valve unit of the type illustrated in Fig. 2 can be simply constructed, for fitting into any spray bar, e.g. of the type used for a valve unit of the type illustrated in Fig. 1. It can give reliable service. A prototype unit has been tested under operating conditions over 60,000 cycles (representing approximately six working years) without any problems. A further 48 units have given reliable contracting service during a continuous period which commenced subsequent to the priority date of this application.

Claims (7)

1. A valve unit comprising a housing defining a chamber having an inlet and an outlet for liquid, an elongate member that can reciprocate in the housing and that has an outlet closure member biased into sealing engagement with the outlet, the unit being adapted for opening of the outlet by external action on the elongate member against the bias, characterised in that the chamber is of fixed volume and the closure member is within the chamber.
2. A valve unit according to claim 1, which includes independent from the chamber, a cylinder and a further inlet for fluid, and the elongate member bears a piston within the cylinder and on which the fluid can act in order to open the outlet.
3. A valve unit according to claim 1 or claim 2, which comprises a port to the elongate member, independent from the chamber and between the chamber and any cylinder as defined in claim 2.
4. A valve unit substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.
5. A spray bar comprising a plurality of valve units according to any preceding claim, the respective chamber inlets being in communication within the bar.
6. A spraying vehicle comprising a spray bar according to claim 5 and means for controlling the opening of the respective chamber outlets.
7. A surface dressing method, which comprises applying the dressing via a spray bar according to claim 5.
GB9406788A 1993-04-07 1994-04-06 Surface dressing equipment and method Expired - Fee Related GB2276932B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP93302749 1993-04-07

Publications (3)

Publication Number Publication Date
GB9406788D0 GB9406788D0 (en) 1994-05-25
GB2276932A true GB2276932A (en) 1994-10-12
GB2276932B GB2276932B (en) 1997-02-05

Family

ID=8214378

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9406788A Expired - Fee Related GB2276932B (en) 1993-04-07 1994-04-06 Surface dressing equipment and method

Country Status (2)

Country Link
FR (1) FR2703702A1 (en)
GB (1) GB2276932B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2303199A (en) * 1995-07-12 1997-02-12 L B Bentley Limited Valve assemblies

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB778031A (en) * 1955-10-24 1957-07-03 W H Heath Ltd Improvements in taps for tea and like urns
US3902695A (en) * 1973-12-13 1975-09-02 Us Energy Valve for cryogenic service
GB2168129A (en) * 1984-11-30 1986-06-11 Alumasc Ltd Dispense tap
EP0235063A1 (en) * 1986-02-05 1987-09-02 Brasseries KRONENBOURG Société dite : S.A. Tap for drawing under pressure a carbonated beverage, especially beer with a controlled head of foam
GB2251918A (en) * 1991-01-19 1992-07-22 Ford Motor Co Gas flow control valve

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2323852A1 (en) * 1973-05-11 1974-11-28 Hermann Beck DEVICE FOR OPENING AND CLOSING SPRING-LOADED CLOSED VALVES OF EQUIPMENT FOR SPRAYING ROADS
FR2455125A1 (en) * 1979-04-27 1980-11-21 Kozuti Gepellato Vallalat Road bitumen spraying vehicle - has pressure meter in pipe, switches and spray pump linked signal transmitter
FR2509338A1 (en) * 1981-07-07 1983-01-14 Pedersen As Marius METHOD FOR DETERMINING THE APPLICATION OF A BINDER ON A PAVEMENT AND DEVICE FOR SPREADING
SE444331B (en) * 1983-02-10 1986-04-07 Dynapac Maskin Ab RAMP VALVE

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB778031A (en) * 1955-10-24 1957-07-03 W H Heath Ltd Improvements in taps for tea and like urns
US3902695A (en) * 1973-12-13 1975-09-02 Us Energy Valve for cryogenic service
GB2168129A (en) * 1984-11-30 1986-06-11 Alumasc Ltd Dispense tap
EP0235063A1 (en) * 1986-02-05 1987-09-02 Brasseries KRONENBOURG Société dite : S.A. Tap for drawing under pressure a carbonated beverage, especially beer with a controlled head of foam
GB2251918A (en) * 1991-01-19 1992-07-22 Ford Motor Co Gas flow control valve

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2303199A (en) * 1995-07-12 1997-02-12 L B Bentley Limited Valve assemblies
GB2303199B (en) * 1995-07-12 1999-09-01 L B Bentley Limited Improvements relating to valve assemblies

Also Published As

Publication number Publication date
GB2276932B (en) 1997-02-05
FR2703702A1 (en) 1994-10-14
GB9406788D0 (en) 1994-05-25

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee