H Series Safety & Back Pressure Valves …

1 H Series Safety & back Pressure ValvesINSTRUCTION MANUAL339-0023-000 Issued 4/20113 TABLE OF CONTENTS Warranty ..visit 1 Introduction ..6 Description ..6 Product Coding ..7 Principle of Operation ..8 Section 2 Installation ..10 Unpacking ..10 Safety Precautions ..10 Installation ..11 Section 3 Operation ..15 Start-Up ..15 Adjusting Set Pressure ..15 Section 4 Maintenance ..19 Recommended Spare Parts ..19 Returning Units to the Factory ..20 Maintenance ..214 TABLE OF CONTENTS (Continued)Section 5 Troubleshooting ..23 back Pressure Valves ..23 Safety Valve ..24 Section 6 Parts ..251/2 Safety Valve Parts List.

2 261 Safety Valve Parts List ..281/2 back Pressure Valve Parts List ..301 back Pressure Valve Parts List ..315 LIST OF ILLUSTRATIONS Figure 1. Safety & back Pressure Valves ..6 Figure 2. Product Code ..7 Figure 3. Safety Valve Installation ..11 Figure 4. back Pressure Valve Installation ..13 Figure 5. Safety Valve Parts Drawing ..25 Figure 6. back Pressure Valve Parts Drawing ..296 Section 1 IntroductionDESCRIPTIONM ilton Roy diaphragm Safety Valves are designed primarily to protect controlled volume pumps and asso-ciated equipment from overpressure. milton Roy back Pressure Valves are engineered to ensure the neces-sary differential back Pressure on controlled volume pumps in specific , milton Roy chemical Safety Valves and back Pressure Valves appear identical except for ar-rows indicating inlet and outlet connections; however, the two Valves differ internally (refer to Figures 5 and 6).

3 The Safety valve has a diaphragm, ball and ball guide. The back Pressure valve on the other hand, does not use a ball because its diaphragm seats directly on the valve seat. The inlet connection for the Safety valve is at the bottom with the outlet connection on the side. For back Pressure Valves with a set Pressure of 70 psi or below, the inlet connection is on the side, and the outlet connection is at the bottom. For back Pressure Valves with 71 psi and higher set pres-Figure 1. Safety & BackPressure Valves areoutwardly identical7 VValve TypeSizeMaterial ofConstruction1 = 316 SS5 = Alloy 20S = SafetyB = back = 1/2"16 = 1"Set Pressure RangeSafety Valves 1"2 = 20-3753 = 376-1000 1/2"2 = 20-494 = 50-3005 = 301-6006 = 601-12007 = 1201-1500 back Press.

4 Valves 1" 2 = 5-35 3 = 36-70 4 = 71-1255 = 126-200 1/2"2 = 5-353 = 36-704 = 71-1005 = 101-200 sure, the inlet connection is on the bottom, and the outlet connectionion is on the side. NOTE:A Safety valve cannot be changed to back Pressure service by simply reversing the CODINGM ilton Roy Safety and back Pressure Valves are available in several different configurations. To deter-Figure 2. Product which features a specific valve has, compare the product code shown on the valve nameplate with Figure 2. The nameplate is located on the upper body of the OF OPERATIONS afety Valves (refer to Figure 5)The milton Roy Safety Valve operates on a differen-tial area principle.

5 The inlet Pressure acts against the ball, and the resulting force is opposed by the CodingMilton Roy Safety and back Pressure Valves are available in several different configurations. To deter-mine which features a specific valve Whenever the inlet Pressure exceeds the set Pressure , the ball rises from the seat. Consequently, a flow of liquid passes through the valve. After the Pressure in the system drops to the point where the force on the diaphragm is insufficient to hold it open, the valve Pressure Valves (refer to Figure 6)The milton Roy back Pressure Valve maintains a set Pressure at the metering pump discharge to insure precise metering and to prevent siphoning* in systems where process Pressure is lower than suction Pressure .

6 During the pump discharge stroke, Pressure acts on the valve diaphragm, lifting it off the back Pressure seat and 9allowing the metered volume of liquid to flow through it. As the pump discharge flow decreases to zero (suc-tion stroke), the diaphragm reseats and traps the liq-uid under Pressure between the pump outlet and the valve. This maintains a constant positive Pressure on the pump discharge check :*Siphoning is prevented only when the pump is producing flow. With the pump turned off, liquid may leak through the valve. If positive siphon shut off is required when the pump flow is at zero, a positive shut off valve should be employed.

7 10 UNPACKINGU nits are shipped FOB factory and the title passes to the customer when the carrier signs for receipt of the unit. In the event that damages occur during shipment, it is the responsibility of the customer to notify the carrier immediately and to file a damage examine the shipping crate upon receipt from the carrier to be sure there is no obvious damage to the contents. Open the crate carefully so accessory items fastened to the inside of the crate will not be dam-aged or lost. Examine all material inside the crate and check against the packing list to be sure that all items are accounted for and PRECAUTIONSWhen installing, operating, and maintaining Safety and/or back Pressure Valves , keep Safety consider-ations foremost.

8 Use proper tools, protective clothing, and eye protection when working on the equipment and install the equipment with a view toward ensuring safe operation. Follow the instructions in this manual and take additional Safety measures appropriate to the liquid being pumped. Be extremely careful in the pres-ence of hazardous substances ( , corrosives, toxics, solvents, acids, caustics, flammables, etc.).SECTION 2 INSTALLATION11 SafetyValveMeteringPumpTo highpressureserviceSelf drainingline to catchbasin orsupply tankPressureGaugeINSTALLATIONS afety Valves (Refer to Figure 5)Generally, a Safety valve should be installed as near as possible to the discharge port of the pump which the valve is to protect.

9 The valve should always be installed upstream of any shut off valve in the discharge line in or-der to protect the pump if a shut off valve should be in-advertently closed while the pump is in operation. Since the milton Roy Safety valve is a diaphragm type, the valve must be installed so that no back Pressure can be applied to the outlet*. This means that the valve must be installed in Figure 3. Safety Valve a Safety valve connected as shown, the pressuresetting can be changed or the internal parts can bereplaced without removing the valve from the a way that it will be self-draining after :The presence of any small Pressure on the outlet can cause valve chattering and variations of actu-ating Pressure .

10 Even a few feet of standing liquid Pressure on the outlet can cause unwanted valve ways of piping the outlet include: (1) directly to a drain, with the piping properly sloped downward from valve to drain, and (2) back to the chemical storage tank, with the valve outlet at the top of the storage tank and piping extending into milton Roy diaphragm Safety valve should not be used: (1) on liquefied gas applications where the outlet cannot be opened to the atmosphere, (2) on any application where the outlet may be subjected to fluid Pressure , (3) across a pump, that is, the valve should never be connected from the discharge side of a pump to the suction side of the :Be sure to install Safety Valves so that the inlet port at the bottom is connected to the system to be protected from overpressure.