US1252376A

US1252376A - Apparatus for heating and applying asphaltic or bituminous materials.

Info

Publication number: US1252376A
Authority: US
Inventors: Willis C Merrill
Original assignee: Individual
Current assignee: Individual
Priority date: 1914-04-15
Filing date: 1914-04-15
Publication date: 1918-01-01
Anticipated expiration: 1935-01-01

Description

W. C. MERRIzLL. APPARATUS.FOR HEATING AND APPLYING ASPHALTIC OR BITUMINOUS MATERIALS.

APPLICATION FI LED. APR. 1.5. 1914.

Patented Jan. 1, 1918.

STATE% PATENT @FFTQE.

WILLIS C. MERRILL, 0F BOSTON, MASSACHUSETTS.

To all whom it may concern:

Be it known that I, WVILLIS C. MERRILL, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Apparatus for Heating and Applying Asphaltic or Bituminous Materials, of which the following is a specification.

My invention relates to road buildin and road spraying machines, that is, mac ines which spray liquid asphalt, or other bitu minous material, onto the roads :either in new road construction by spraying liquid asphalt, or other bituminous material, into the interstices of the road material to serve as a binder, or to give an asphaltic surface and to repair and patch roads already constructed, by spraying the asphaltic or bituminous material, on to the surface of old roads. The road sprayin machines for building or surfacing roads or repairing the same, at present in use, depend either upon steam of ordinary pressure, that is 50 to 80 lbs., with a temperature of about 300 F., or direct heat passed through tubes similar to flue tubes of a boiler to heat the material contained in the tank or other receptacle to liquefy the material sufficiently to spray the liquid onto the road.

In the first instance where steam is em ployed to heat the material, the method is ineffective, owing to the comparatively low temperature of the steam at ordinary pressures, used to raise the contained mass (1' uid asphalt, or other bituminous materialig to the temperature required.

In the second instance where direct heat is passed through flues or otherwise directly communicated to the contained mass, the method is undesirable, as it is attended with more or less danger of injury to the material heated in the tank, owing to the high temperature of the direct heat, as it is a well-known fact, that asphaltic base, or-

bituminous road materials, carbonize at tem per-atures easily reached by direct heat, and where direct heat is used it is difficult of control, as the temperatures range higher than the danger point of carbonization in the contained mass.

The carbonizing of the heated mass in the treating tank tends to disintegrate the asphaltic or bituminous material, and to reduce the cohesive and resilient qualities thereof when applied to the road.

The mass of the liquid asphalt, or other Specification of Letters Patent.

Patented Jan. 1, 19318.

Application filed April 15, 1914. Serial No. 831,922.

bituminous material, has great cohesion of its particles and does not freely circulate, and said materials also have great density, which prevents heat from rea ily permeating the same.

The direct introduction of -steam to the main or treating tank, either intentionally or through leakage in steam coils, when containing asphaltic or bituminous material used in road construction, is usually accompanied by serious trouble from the foaming effect of moisture in the steam, and the use of steam to liquefy asphaltic or bituminous material for road building is open to the objection that too high pressures have to be carried consistent with safety, for the purpose of raising the temperature of the asphaltic material so as to liquefy the same to a degree sutlicient to apply it in a spray. The objection to this high steam pressure is, first, the difficulty of keeping the steam joints tight, and the further objection to the introduction of steam and water by leakage into the asphaltic mass while it is heating, which causes it to foam. This emulsifies the material and causes it to expand and boil over and when it is applied to the road causes the liquid asphalt to froth. This foaming of the liquid asphalt prevents a good application of it to the road because the liquid material leaving the spray nozzle is frothy and not a continuous free flowing liquid. When such high pressures are used it becomes a danger in the hands of careless workmen and a menace in passing through the streets. These high pressures also necessitate the use of very heavy boiler plate which adds to the weight and expense of the apparatus.

In carrying out my invention both of these objectionable methods above referred to are avoided, and it is possible in my machine to obtain a high temperature, 450 F. or more, within the limits of safety without injury to the material, due to carboniza- ,tions, foaming, etc.

liquids of light gravity, as the mass chills very easily and defeats the purpose of spraying effectively, both as to penetration and facility of application. By penetration it is understood that the asphaltic or bituminous material penetrates under pressure, or by natural causes, the interstices in the road material, and by its cohesive properties, the asphaltic or bituminous material then binds the road material together on cooling.

The main object of my invention therefore is to produce a machine in which there is secured as high a temperature within the limits of safety, as regards the injury to the material to be applied, as is practicable and economical, and to make an application of the material to the road surface, to which the material is to be applied, at as high a temperature as it is possible to secure, without danger of carbonization and injury to the material to be applied.

This and other objects are attained by the mechanism hereinafter described and particularly pointed out in the claims.

In operating my machine I introduce:

(a). The liquid asphalt or other bituminous material at a temperature ranging from 125 F. to 200 F. or more, from a stationary heating storage or supply tank into a tank on the machine through a suitable inlet, and the material is then heated in the tank as described below to the proper temperature by the means therein described, and the material when so heated is distributed through suitable outlet and spray pipes onto the road under pressure. Or,--

(6) The asphaltic or bituminous material may be introduced in a solid or semi-liquid form into the tank, without preliminary heating, and gradually heated to melting point in the tank by the same device as described herein, and then raised to the required temperature by the same means, thus avoiding the use of the preliminary heat ing or supply tank. After the material has been introduced into the tank the inlet is closed and heat applied through suitable conductors and a heated circulating medium employed to raise the temperature of the contained mass in the tank to 350 F., more or less, and to keep it in a liquid condition. A circulating pump or other circulating mechanism is employed to keep this heating medium in constant motion and in its transit it is brought in contact with high temperatures such as would be produced by burning fuel oil, kerosene, gas or other heat producing material, and the circulating medium is advanced or pushed forward by the circulating pump and the heat units stored in this mediumare transferred to the mass of lower temperature contained within the tank. The advantage of this continuous circulation consists in using a medium that does not condense at a low temperature and does not concentrate the heat applied so as to carbonize the material under treatment because the heat units stored in this medium are under control and the temperature of the medium at no time reaches a point that injures the. integrity of the'contained mass in the tank. Any suitable, hand-operated control, or thermostat may be used to regulate the degree of temperature that may be desired.

This method of a self-contained circulat ing medium offers advantages in the facility with which it is possible to heat the contained mass in the tank, as a heat producer, like fuel oil or kerosene, can be utilized to heat the contained mass in the tank during transit from loading station to point of application so that when the machine reaches its destination the work of application can begin at once if desired, as theliquid asphalt, or bituminous material. is in the desired condition to be readily applied.

To expel the contained material in the tank under pressure I employ air at from 3to 5' atmospheres, that is, I employ free air compressed from 3 to 5 atmospheres. The common appliances for controlling the pressure are employed. This compressed air enters the closed tank preferably having first passed through an auxiliary tank in which it is stored and the excess air from the auxiliary tank passes over into the main tank. Upon openin the outlet valve the contained mass being under this pressure immediately passes the outlet through the line of pipe to the spray nozzles.

After the mass has been raised to the required temperature, hot compressed air contained in the tank which is at a temperature of the inclosed mass is admitted through an outlet pipe to the spraying mechanism to raise the temperature of this mechanism so that the outgoing material to be applied to the road will reach the road in its application at as high a temperature as possible and at substantially the same' temperature as in the tank. The outlet valve is inclosed in a valve box through which the circulating heating medium passes and raises the tem-' perature of this valve box and valve to that of the tank, which keeps the valve hot and facilitates the easy opening and closing of the valve, and also prevents the chilling or solidification of the asphaltic or bituminous material, when passing through the valve.

Suitable connections are made from the auxiliary air tank to the fuel oil tank so that pressure is maintained on 'the fuel, and also a suflicient quantity of air supplied to the burner to maintain combustion as required by commercial devices in use. A suitable coil is inclosed in a heating recep tacle and is surrounded by the heat generated by the means necessary to heat the circulating medium contained in the coil. The medium circulating through th s coil is emme heated by being brought in contact with the heat produced by the heating device and this heat is transmitted to the mass Within the perature,

tank by means of the circulating coils arranged in the tank.

I claim for this machine an original device for heating solid or semi-liquid asphalt, or bituminous material, to temperatures at which those materials must be applied in bituminous road construction and repair by means of a heat medium which is liquid and easily controlled, and capable of being heated to the exact temperature which it is necessary to give this asphaltic or bituminous material when applied to the road, so that this heating medium will heat the asphaltic or bituminous material to that tembut will not during that process apply excessive heat to it in any part 'to injure the asphalticor bituminous material 7 by overheating any part before themass has attained the uniform temperature required.

A great advantage in using a heating medium having a higher boiling point than water lies in the fact that by this means I arm able to convey the heat required without vaporization, and it is possible to get a higher temperature than it is practicable to get with steam. The further advantage of using a fluid with a high boiling point is that more heat units are stored and delivered in a given time without condensation loss; also the freedom from excessive pressure removes the danger attending the use of steam as a heating medium.

In the accompanying drawings which illustrate a construction embodying my invention':

Figure 1 is a side elevation of the apparatus partly broken away to show interior parts.

Fig; 2 is an enlarged detail view of the valve which controls the flow of liquid asphalt, or other bitumiilous material, from the tank to the spraying head and thence to the road.

Fig. 3 is a detail sectional view of the thermostatic device hereinafter described.

Like characters of reference refer to like parts in both views.

The motor truck A is of any desired contion, the tank B receives liquid asphalt, or other bituminous material at a temperature of 150 to 200 F. or more. The asphaltio or other bituminous material may also be introduced in a solid or semi-liquid form into the tank and then raised to the required temperature by the same means. This material by any suitable connection passes through a strainer or perforated basket B secured in place in the nozzle C closed by a suitable cover B which is secured in place in any suitable manner after the liquid asphalt, or bituminous material, has reached the desired height in the tank B. B is a suitable manhole cover.

From a suitable source, as the expansion tank N and the pipe N, a pump or other circulating medium E receives a liquid medium having a higher boiling point than 212 F. which is circulated and heated to raise the temperature in the tank B. This pump E forces this heating medium through the pipe E into the valve box L and out from the valve box L to the pipe E connecting at F with the heating coil F located within the heater G. The heated medium then passes from the coil F out at F to the coil F arranged in the tank B as a spiral coil embracing the axis of said tank and located adjacent to but preferably out of contact with the wall of said tank B and then back to the pump E through the pipe E. This heated medium is kept in circulation through this closed circulating conduit and brings the temperature of the contained asphaltic or other bituminous material to about 350 F. When the coil F is full of circulating oil, any expansion of this oil in the said coil is provided for.by

the usual expansion tank N into which the expanded oil flows through the pipe N. The fuel oil for the heater G is stored in a tank Gr on the truck and is under suitable air pressure by means of the pipe Gr leading from an air storage tank H connected to the pump J. This air pressure forces the oil through a pipe G to the heater G and supplies sufficient quantity of air to the burner to maintain combustion as required by such devices. The flame from the oil jet G passes around the baffle plate G and then envelops the coil F and the waste products of lbs. per square inch, dueto the friction of the heating fluid passing through the pipes and not due to the temperature of the circulating heating fluid, is maintained in the circulating coils, all the difficulties encountered' in the use of steam are obviated and the danger of foaming is also entirely removed. Furthermore there is no pressurewithin the interior of the tank containing asphaltic material during the heating of this material by this circulating oil for the reason that the heating medium is all contained in a tight circulating coil and is kept circulating, and furthermore the expansion of the oil is taken care of by the expansion tank N provided on the exterior of the tankv containing the asphaltic material. Now when the coil is full of circulating oil, any expansion of this oil in the conduit or coil is provided for by the expansion tank N into which the expanded oil flows through the pipe N, and relieves the pressure in the system, so that the danger of explosion is avoided and constant supervision unnecessary.

The air pump J forces air under pressure into the storage tank H past a suitable check valve K and by a suitable hand operated valve H and check valve H located in the pipe H, the compressed air passes through the pipe H to the nozzle C where it enters the top of the tank B and exerts a pressure on the top of the liquidasphalt, or other bituminous material, contained in the tank. A pipe L leads froin the bottom of the tank B to the valve L (Fig. 2) and from. the valve L there leads a pipe L to the spray head L and spray nozzle L from which the 80 material is sprayed on to the road. This valve L is located in the valve boX L of an suitable construction and arrangement and said valve L is kept heated by the hot cir culating medium passing into and through the surrounding valve box L forming a part of the closed circulating conduit hereinbefore described. This heating of the valve keeps it in condition so that it can be readily operated and especially in cold weather when otherwise the asphaltic or bituminous material to be applied on the road would be chilled or solidified by coming in contact with the cold valve and pipes before reaching the sprayers. By means of the spiral coil F the heating medium is circulated around and through a large proportion of the contents of tank B and heat is radiated from said coil F pri marily to the peripheral portion of said contents which is desirable in view of the shape of said tank B and of the fact that as such contents are lowered in such tank the pcripheral portions thereof follow the extensions of the pipe coils and receive heat therefrom. Such arrangement of pipe F also supplies a very practical means for supplying heat to the air in the upper portion of the tank B.

A dome L having a suitable safety valve L for preventing damage from such pressure is connected to tank B at its top. From the casing of this safety valve there leads apipe L which connects with and opens into the pipe L through a suitable nozzle F 66 and by means of which this discharge pipe L can be heated to a condition to facilitate the flow of the liquid road material to the spray nozzle L from which it is sprayed or delivered on to the road. Asuitable hand operated valve L is located in this pipe L for controlling the same when desired. The valve L which controls the flow of .the liquid asphalt, or bituminous material, from the tank to the spray nozzle L under the air pressure previously described has a stem M to which is connected at M a lever to M pivoted to a suitable support M and M and its lower end, M is pivotallyconnected at M to the connecting rod or link VI, which in turn is pivotally connected to the lever M pivoted to the frame at M and provided with asuitable foot treadle M for the attendant. A suitable compression spring M is located around the movable rod M sl-idv able in the lower end of the bracket M and said spring M normally tends to close the valve L at all times excepting when the foot treadle M is depressed by the attendant to open the valve L through the connections above described. The operating foot lever may be located at the rear of the machine or, any other suitable place as desired; so that in case of accident or otherwise, such as the absence of the attendant, the valve L is kept closed and no liquid asphalt, or bituminous material, can flow excepting when desired and thus waste of the material is avoided.

As a means for heating the air leading from the top of the tank B to the discharge outlet pipe, L, it may be passed through a 10 coil P in the top of the gas heater G where the air is heated and passed from the coil out through the pipe L to the nozzle L" where it is discharged into the discharge pipe L to heat the same to facilitate the flow of the liquid to the spray nozzle L".

Located at any desired point in the conduit or pipe E through which the circulating heating fluid circulates is a thermostat 0 operating the valve 0 in the valve joint O and controlling the supply of fuel from the tank G through the gipe G to the burner G of the oil heater The object of this thermostat is to regulate the temperature of the circulating fluid so that it will not'rise above a predeter mined oint, at which point the asphalticor other bituminous material liquefies to a proper degree or attains a temperature at which it is proper to apply to the surface of the road.

This thermostatwhich may be set at a predeterminedpoint, say 450? F. will prevent the temperature of the circulating heat- .in medium rising above this point which brings the temperature of the material under treatment in the tank to about 350 F., which is about the point' where the asphaltic or other bituminous material liquefies to a proper degree to be applied to the road, and this means of preventin the temperature rising above this point Keeps the mass at the desired temperature. Now,

if the temperature of the circulating fluid a or the mass heated by the fluid should fall below the desired temperatures the operation of the thermostat is to release fuel to the burner and raise the temperature. In other words, the valve operated by the thermostat opens or closes depending upon the temperature of the circulating heating fluid.

The principal object obtained by this thermostatic control, is that the mass to be heated never rises above the regulated temaaperature within the limits of safety to the asphaltic or other bituminous material.

In practice by this method no material loss of this circulating heating medium of high boiling point occurs, as the temperature at which vaporization would take place is not approached, and the heating me ium bein a non-elastic liquid differs from a con ensable elastic fluid like steam.

While I have described my invention as especially adapted to the treatment of asphalt for road work owing to the high temperature necessary to properly liquefy for road application, yet it will be understood that my invention may be used with equal facility on other substances suitable for road making or repairing or other uses and purposes, such as coal tar, asphaltic oils, molasses, and other viscous materials which require heating to properly liquefy the same for road building or other uses and purposes, and although these last named substances .do not require the high temperatures necessary with the asphalt, yet the advantages of my method of heating will be manifest to one skilled in the art, for various purposes, such as storage tanks, tank cars and tank ships, from which the material liquefied or rendered less viscous by my method of heating is adapted to readily dischar e owin to its fluidity.

I not limit myself to the arrangement or construction shown, as the same may be varied without departing from the spirit of my invention.

Having thus described the construction embodying my invention, what I claim and now desire to secure by Letters Patent in the United States, I31?- 1. In an apparatus of the character described, a receptacle for asphalt, bituminous or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a valve controlling said discharge outlet, a source of heating fluid having a boiling point above 212 F., a continuous conduit passing through said receptacle and includmg in its circuit said discharge outlet an d through which conduit said heating flu d 1s circulated, means for heatlng said circuscribed, a closed lating heating fluid to raise the temperature of the viscous material in the receptacle to heat or liquefy the said material and to heat the discharging material, and means for cirrczlulating said heating fluid through said conuit.

2. In an apparatus of the character described, a receptacle for asphalt, bituminous or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a valve controlling said discharge outlet, a source of heating fluid having a boiling point above 212 F., a continuous conduit passing through said receptacle and including in its circuit-said discharge outlet and through which conduit said heating fluid is circulated, means for heating said circulating heating fluid to raise the temperature of the viscous material in the receptacle to heat or liquefy the said material and to heat the discharging material, means for circulating said heating fluid through said conduit, and means for applying a pressure to the material in said receptacle above that of the atmosphere so as to force the material from the receptacle through the said discharge outlet.

3. In an apparatus of the character described, a closed tank for asphalt, bituminous or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a valve controlling said discharge outlet, means for applying a pressure to the material in said tank above that of the atmosphere so as to force the material in said tank through the said discharge outlet, a source of heating fl lid, a continuous conduit through which said heating fluid is circulated for raising the temperature of the viscous material in the tank to liquefy or I render the material less viscous, means for 1 heating said circulating heating fluid, a valve box included in sald conduit and surrounding the discharge outlet valve so as to heat said valve by the said circulating heating fluid, and means located on the exterior of said valve box for opening and closing said valve.

4. In an apparatus of the character detank for asphalt, bituminous or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a valve controlling Studd15- charge outlet, means for applying a pressure to the material in said tank above that of the atmosphere so as to force the material i' .1 the tank through the'said discharge outlet, a source of heating fluid, a continuous conduit through which said heating fluid is circulated for raising the temperature of the viscous material in the tank to liquefy or render the material less viscous, 180

outlet, a valve controlling said dischargemeans for heating said circulating heating fluid, a valve box included in said conduit and surrounding the discharge outlet valve so as to heat said valve by the same circulating heating fluid, and means located on the exterior of said valve box for opening said valve and for automatically closing ,said valve.

5. In an apparatus of the character described, a closed tank for asphalt, bitumi-- nous or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a valve controlling said discharge outlet, means for applying a pressure to the material in said tank above that of the atmosphere so as to force the material from the tank through the said discharge outlet, a source of heating fluid, a continuous conduit through which a heating fluid having said boiling point higher than 212 F. is circulated for raising the temperature of the Viscous material in the tank to liquefy or render the material less viscous, means for heating said circulating heating fluid, and a valve box included in said conduit and surrounding the discharge outlet valve so as to heat said valve by the said circulating heating fluid. a

6. In an apparatus of the character described, a closed tank for asphalt, bituminous or other materials re uiring heat to render them liquid or less vlscous andprovided with an inlet and with a discharge outlet, a valve controlling said discharge outlet, means for applying a pressure to the material in said tank above that of the atmosphere so as to force the'material from the tank through thesaid discharge outlet, a source of heating fluid, a continuous conduit through which a heating fluid having said boiling point higher than 212 F. is circulated for raising the temperature of the viscous material in the tank to liquefy or render the mateial less viscous, means for heating said circulating heating fluid, a valve box included in said conduit and surrounding the discharge'outlet valve so as to heat said valve by thesaid circulating heating fluid,'and means adapted to control the supply of fuel to the heater upon the temperatureof the heating circulatingfluid reaching a predetermined point.

7. In an apparatus of the character described, a closed tank for asphalt, bituminous or other-materials requiring heatto render them liquid or lessviscous and provided with aninlet and with a discharge outlet, means for applying a pressure to the material in said tank above that of the at mosphere so as to force the material from the tank through the said discharge outlet, a source of heating fluid, a continuous con- -means for applying a pressure to the mateduit through which a heating fluidhaving said boiling point higher than 212 F. is circulated for raising the temperature of the viscous material in the tank to liquety or render the material less viscous, means for heating said circulating heating fluid, a valve box included in said conduit and surrounding the discharge outlet valve so as to heat said valve by the said circulating heating fluid, and automatic means adapted to control the supply of fuel to the heater upon the temperature of the heating circulating fluid reaching a predetermined point.

8. In an apparatus of the character described, a receptacle for asphalt, bituminous or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a Valve controlling said discharge outlet,

means for applying a pressure tothe mate- .atmosphere'so as to force the material'from the receptacle through the said discharge outlet, a source of heating fluid supply, a continuous conduit through which said heating fluid having a boiling point above 212 F. is circulated for raising the temperature of the material in the receptacle to heat or liquefy the said material and including in its circuit the said discharge outlet to heat the discharging material, means for heating said circulating heating fluid, means included in said conduit and in the path of the said circulating heating fluid for circulating said heating fluid through said conduit, and a valve box included in said conduit and surrounding said discharge outlet valve so'as to heat said valve by the said circulating heating fluid; I 1 i o 9; In an apparatus of the character do scribed, a, receptacle for asphalt,"bituminous 105 or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with adischarg'ef outlet,

a valve controlling said'disc'harge outlet,

rial in said receptacle above that of the atmosphere so as to force the material from the receptacle through the said discharge outlet, a source of heating fluid supply, a continuous conduit through which said heating fluid having a boiling point above 212 F. is circulated for raising the temperatureof the material in the receptacle to heat or 'liquefy the said material and including in its circuit the said discharge outlet to heat the discharging'material, means for heating said circulating heating fluid, a valve box included insald conduit and surrounding said discharge outlet valve so as to heat said valve by the said heating fluid, auto matic means adapted to control the supply of fuel to the heater upon the temperature of the said heating circulating fluid reach- 'or other materials requiring heat to render them liquid or less viscous and provided with an inlet and with a discharge outlet, a valve controlling said discharge outlet, a

source of heating fluid, a continuous conduit passing through said receptacle and including in its circuit the said discharge outlet and through which said conduit said heating fluid is circulated, means for heating said circulating heating fluid to raise the temperature of the viscous material in the receptacle to heat or liquefy the said material and to heat the discharging material, and means for circulating said heating fluid through said conduit.

11. In an apparatus of the character described, areceptacle for asphalt, bituminous or other materials requiring heat to render them liquid or less viscous and provided with an inletand with a discharge outlet,

a valve controllin said discharge outlet, a source of heating 1 uid, a continuous conduit passing through said receptacle and including in its circuit the said discharge outlet and through which said conduit said heating fluid is circulated, means for heating said circulating heating fluid to raise the temperature of the viscous material in the receptacle to heat or liquefy the said material and to heat the discharging material, means for circulating said heating fluid through said conduit, and means for applying a pressure to the material in said-receptacle above that of the atmosphere so as to force the material from the receptacle through the said discharge outlet.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses, this eleventh day of April, A. D. 1914.

ILLIS o. MERRILL.

Witnesses:

GERTRUDE M. MARTIN, HAROLD J. HAM.